Merge branch 'main' into cymruu/payload-unit-test

.dockerignore

@@ -2,4 +2,3 @@ target
 Dockerfile
 .dockerignore
 .gitignore
-**/.git

.github/scripts/check-release.sh

@@ -1,24 +1,41 @@
-#!/bin/bash
+#!/usr/bin/env bash
+set -eu -o pipefail
 
-# check_tag $current_tag $file_tag $file_name
+check_tag() {
-function check_tag {
+    local expected=$1
-  if [[ "$1" != "$2" ]]; then
+    local actual=$2
-      echo "Error: the current tag does not match the version in Cargo.toml: found $2 - expected $1"
+    local filename=$3
-      ret=1
+
+    if [[ $actual != $expected ]]; then
+        echo >&2 "Error: the current tag does not match the version in $filename: found $actual, expected $expected"
+        return 1
     fi
 }
 
+read_version() {
+    grep '^version = ' | cut -d \" -f 2
+}
+
+if [[ -z "${GITHUB_REF:-}" ]]; then
+    echo >&2 "Error: GITHUB_REF is not set"
+    exit 1
+fi
+
+if [[ ! "$GITHUB_REF" =~ ^refs/tags/v[0-9]+\.[0-9]+\.[0-9]+(-[a-z0-9]+)?$ ]]; then
+    echo >&2 "Error: GITHUB_REF is not a valid tag: $GITHUB_REF"
+    exit 1
+fi
+
+current_tag=${GITHUB_REF#refs/tags/v}
 ret=0
-current_tag=${GITHUB_REF#'refs/tags/v'}
 
-file_tag="$(grep '^version = ' Cargo.toml | cut -d '=' -f 2 | tr -d '"' | tr -d ' ')"
+toml_tag="$(cat Cargo.toml | read_version)"
-check_tag $current_tag $file_tag
+check_tag "$current_tag" "$toml_tag" Cargo.toml || ret=1
 
-lock_file='Cargo.lock'
+lock_tag=$(grep -A 1 '^name = "meilisearch-auth"' Cargo.lock | read_version)
-lock_tag=$(grep -A 1 'name = "meilisearch-auth"' $lock_file | grep version | cut -d '=' -f 2 | tr -d '"' | tr -d ' ')
+check_tag "$current_tag" "$lock_tag" Cargo.lock || ret=1
-check_tag $current_tag $lock_tag $lock_file
 
-if [[ "$ret" -eq 0 ]] ; then
+if (( ret == 0 )); then
     echo 'OK'
 fi
 exit $ret

.github/workflows/fuzzer-indexing.yml

@@ -0,0 +1,24 @@
+name: Run the indexing fuzzer
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  fuzz:
+    name: Setup the action
+    runs-on: ubuntu-latest
+    timeout-minutes: 4320 # 72h
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+
+      # Run benchmarks
+      - name: Run the fuzzer
+        run: |
+          cargo run --release --bin fuzz-indexing

.github/workflows/publish-apt-brew-pkg.yml

@@ -35,7 +35,7 @@ jobs:
     - name: Build deb package
       run: cargo deb -p meilisearch -o target/debian/meilisearch.deb
     - name: Upload debian pkg to release
-      uses: svenstaro/upload-release-action@2.5.0
+      uses: svenstaro/upload-release-action@2.6.1
       with:
         repo_token: ${{ secrets.MEILI_BOT_GH_PAT }}
         file: target/debian/meilisearch.deb

.github/workflows/publish-binaries.yml

@@ -54,7 +54,7 @@ jobs:
     # No need to upload binaries for dry run (cron)
     - name: Upload binaries to release
       if: github.event_name == 'release'
-      uses: svenstaro/upload-release-action@2.5.0
+      uses: svenstaro/upload-release-action@2.6.1
       with:
         repo_token: ${{ secrets.MEILI_BOT_GH_PAT }}
         file: target/release/meilisearch
@@ -87,7 +87,7 @@ jobs:
     # No need to upload binaries for dry run (cron)
     - name: Upload binaries to release
       if: github.event_name == 'release'
-      uses: svenstaro/upload-release-action@2.5.0
+      uses: svenstaro/upload-release-action@2.6.1
       with:
         repo_token: ${{ secrets.MEILI_BOT_GH_PAT }}
         file: target/release/${{ matrix.artifact_name }}
@@ -121,7 +121,7 @@ jobs:
       - name: Upload the binary to release
         # No need to upload binaries for dry run (cron)
         if: github.event_name == 'release'
-        uses: svenstaro/upload-release-action@2.5.0
+        uses: svenstaro/upload-release-action@2.6.1
         with:
           repo_token: ${{ secrets.MEILI_BOT_GH_PAT }}
           file: target/${{ matrix.target }}/release/meilisearch
@@ -183,7 +183,7 @@ jobs:
       - name: Upload the binary to release
         # No need to upload binaries for dry run (cron)
         if: github.event_name == 'release'
-        uses: svenstaro/upload-release-action@2.5.0
+        uses: svenstaro/upload-release-action@2.6.1
         with:
           repo_token: ${{ secrets.MEILI_BOT_GH_PAT }}
           file: target/${{ matrix.target }}/release/meilisearch

.github/workflows/publish-docker-images.yml

@@ -58,13 +58,9 @@ jobs:
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v2
-        with:
-          platforms: linux/amd64,linux/arm64
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v2
-        with:
-          platforms: linux/amd64,linux/arm64
 
       - name: Login to Docker Hub
         uses: docker/login-action@v2
@@ -92,13 +88,10 @@ jobs:
           push: true
           platforms: linux/amd64,linux/arm64
           tags: ${{ steps.meta.outputs.tags }}
-          builder: ${{ steps.buildx.outputs.name }}
           build-args: |
             COMMIT_SHA=${{ github.sha }}
             COMMIT_DATE=${{ steps.build-metadata.outputs.date }}
             GIT_TAG=${{ github.ref_name }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
 
       # /!\ Don't touch this without checking with Cloud team
       - name: Send CI information to Cloud team

.github/workflows/sdks-tests.yml

@@ -3,6 +3,11 @@ name: SDKs tests
 
 on:
   workflow_dispatch:
+    inputs:
+      docker_image:
+        description: 'The Meilisearch Docker image used'
+        required: false
+        default: nightly
   schedule:
     - cron: "0 6 * * MON" # Every Monday at 6:00AM
 
@@ -11,13 +16,28 @@ env:
   MEILI_NO_ANALYTICS: 'true'
 
 jobs:
+  define-docker-image:
+    runs-on: ubuntu-latest
+    outputs:
+      docker-image: ${{ steps.define-image.outputs.docker-image }}
+    steps:
+      - uses: actions/checkout@v3
+      - name: Define the Docker image we need to use
+        id: define-image
+        run: |
+          event=${{ github.event_name }}
+          echo "docker-image=nightly" >> $GITHUB_OUTPUT
+          if [[ $event == 'workflow_dispatch' ]]; then
+            echo "docker-image=${{ github.event.inputs.docker_image }}" >> $GITHUB_OUTPUT
+          fi
 
   meilisearch-js-tests:
+    needs: define-docker-image
     name: JS SDK tests
     runs-on: ubuntu-latest
     services:
       meilisearch:
-        image: getmeili/meilisearch:nightly
+        image: getmeili/meilisearch:${{ needs.define-docker-image.outputs.docker-image }}
         env:
           MEILI_MASTER_KEY: ${{ env.MEILI_MASTER_KEY }}
           MEILI_NO_ANALYTICS: ${{ env.MEILI_NO_ANALYTICS }}
@@ -47,11 +67,12 @@ jobs:
         run: yarn test:env:browser
 
   instant-meilisearch-tests:
+    needs: define-docker-image
     name: instant-meilisearch tests
     runs-on: ubuntu-latest
     services:
       meilisearch:
-        image: getmeili/meilisearch:nightly
+        image: getmeili/meilisearch:${{ needs.define-docker-image.outputs.docker-image }}
         env:
           MEILI_MASTER_KEY: ${{ env.MEILI_MASTER_KEY }}
           MEILI_NO_ANALYTICS: ${{ env.MEILI_NO_ANALYTICS }}
@@ -73,11 +94,12 @@ jobs:
         run: yarn build
 
   meilisearch-php-tests:
+    needs: define-docker-image
     name: PHP SDK tests
     runs-on: ubuntu-latest
     services:
       meilisearch:
-        image: getmeili/meilisearch:nightly
+        image: getmeili/meilisearch:${{ needs.define-docker-image.outputs.docker-image }}
         env:
           MEILI_MASTER_KEY: ${{ env.MEILI_MASTER_KEY }}
           MEILI_NO_ANALYTICS: ${{ env.MEILI_NO_ANALYTICS }}
@@ -103,11 +125,12 @@ jobs:
           composer remove --dev guzzlehttp/guzzle http-interop/http-factory-guzzle
 
   meilisearch-python-tests:
+    needs: define-docker-image
     name: Python SDK tests
     runs-on: ubuntu-latest
     services:
       meilisearch:
-        image: getmeili/meilisearch:nightly
+        image: getmeili/meilisearch:${{ needs.define-docker-image.outputs.docker-image }}
         env:
           MEILI_MASTER_KEY: ${{ env.MEILI_MASTER_KEY }}
           MEILI_NO_ANALYTICS: ${{ env.MEILI_NO_ANALYTICS }}
@@ -127,11 +150,12 @@ jobs:
         run: pipenv run pytest
 
   meilisearch-go-tests:
+    needs: define-docker-image
     name: Go SDK tests
     runs-on: ubuntu-latest
     services:
       meilisearch:
-        image: getmeili/meilisearch:nightly
+        image: getmeili/meilisearch:${{ needs.define-docker-image.outputs.docker-image }}
         env:
           MEILI_MASTER_KEY: ${{ env.MEILI_MASTER_KEY }}
           MEILI_NO_ANALYTICS: ${{ env.MEILI_NO_ANALYTICS }}
@@ -139,7 +163,7 @@ jobs:
           - '7700:7700'
     steps:
       - name: Set up Go
-        uses: actions/setup-go@v3
+        uses: actions/setup-go@v4
         with:
           go-version: stable
       - uses: actions/checkout@v3
@@ -156,11 +180,12 @@ jobs:
         run: go test -v ./...
 
   meilisearch-ruby-tests:
+    needs: define-docker-image
     name: Ruby SDK tests
     runs-on: ubuntu-latest
     services:
       meilisearch:
-        image: getmeili/meilisearch:nightly
+        image: getmeili/meilisearch:${{ needs.define-docker-image.outputs.docker-image }}
         env:
           MEILI_MASTER_KEY: ${{ env.MEILI_MASTER_KEY }}
           MEILI_NO_ANALYTICS: ${{ env.MEILI_NO_ANALYTICS }}
@@ -180,11 +205,12 @@ jobs:
         run: bundle exec rspec
 
   meilisearch-rust-tests:
+    needs: define-docker-image
     name: Rust SDK tests
     runs-on: ubuntu-latest
     services:
       meilisearch:
-        image: getmeili/meilisearch:nightly
+        image: getmeili/meilisearch:${{ needs.define-docker-image.outputs.docker-image }}
         env:
           MEILI_MASTER_KEY: ${{ env.MEILI_MASTER_KEY }}
           MEILI_NO_ANALYTICS: ${{ env.MEILI_NO_ANALYTICS }}

.github/workflows/test-suite.yml

@@ -43,7 +43,7 @@ jobs:
           toolchain: nightly
           override: true
       - name: Cache dependencies
-        uses: Swatinem/rust-cache@v2.2.1
+        uses: Swatinem/rust-cache@v2.4.0
       - name: Run cargo check without any default features
         uses: actions-rs/cargo@v1
         with:
@@ -65,7 +65,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - name: Cache dependencies
-        uses: Swatinem/rust-cache@v2.2.1
+        uses: Swatinem/rust-cache@v2.4.0
       - name: Run cargo check without any default features
         uses: actions-rs/cargo@v1
         with:
@@ -105,6 +105,29 @@ jobs:
           command: test
           args: --workspace --locked --release --all-features
 
+  test-disabled-tokenization:
+    name: Test disabled tokenization
+    runs-on: ubuntu-latest
+    container:
+      image: ubuntu:18.04
+    if: github.event_name == 'schedule'
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install needed dependencies
+        run: |
+          apt-get update
+          apt-get install --assume-yes build-essential curl
+      - uses: actions-rs/toolchain@v1 
+        with: 
+          toolchain: stable 
+          override: true 
+      - name: Run cargo tree without default features and check lindera is not present
+        run: |
+          cargo tree -f '{p} {f}' -e normal --no-default-features | grep lindera -vqz
+      - name: Run cargo tree with default features and check lindera is pressent
+        run: |
+          cargo tree -f '{p} {f}' -e normal | grep lindera -qz
+                
   # We run tests in debug also, to make sure that the debug_assertions are hit
   test-debug:
     name: Run tests in debug
@@ -123,7 +146,7 @@ jobs:
           toolchain: stable
           override: true
       - name: Cache dependencies
-        uses: Swatinem/rust-cache@v2.2.1
+        uses: Swatinem/rust-cache@v2.4.0
       - name: Run tests in debug
         uses: actions-rs/cargo@v1
         with:
@@ -142,7 +165,7 @@ jobs:
           override: true
           components: clippy
       - name: Cache dependencies
-        uses: Swatinem/rust-cache@v2.2.1
+        uses: Swatinem/rust-cache@v2.4.0
       - name: Run cargo clippy
         uses: actions-rs/cargo@v1
         with:
@@ -161,7 +184,7 @@ jobs:
           override: true
           components: rustfmt
       - name: Cache dependencies
-        uses: Swatinem/rust-cache@v2.2.1
+        uses: Swatinem/rust-cache@v2.4.0
       - name: Run cargo fmt
         # Since we never ran the `build.rs` script in the benchmark directory we are missing one auto-generated import file.
         # Since we want to trigger (and fail) this action as fast as possible, instead of building the benchmark crate

Cargo.toml

@@ -13,7 +13,8 @@ members = [
     "filter-parser",
     "flatten-serde-json",
     "json-depth-checker",
-    "benchmarks"
+    "benchmarks",
+    "fuzzers",
 ]
 
 [workspace.package]

Dockerfile

@@ -1,4 +1,3 @@
-# syntax=docker/dockerfile:1.4
 # Compile
 FROM    rust:alpine3.16 AS compiler
 
@@ -12,7 +11,7 @@ ARG     GIT_TAG
 ENV     VERGEN_GIT_SHA=${COMMIT_SHA} VERGEN_GIT_COMMIT_TIMESTAMP=${COMMIT_DATE} VERGEN_GIT_SEMVER_LIGHTWEIGHT=${GIT_TAG}
 ENV     RUSTFLAGS="-C target-feature=-crt-static"
 
-COPY    --link . .
+COPY    . .
 RUN     set -eux; \
         apkArch="$(apk --print-arch)"; \
         if [ "$apkArch" = "aarch64" ]; then \
@@ -31,7 +30,7 @@ RUN     apk update --quiet \
 
 # add meilisearch to the `/bin` so you can run it from anywhere and it's easy
 # to find.
-COPY    --from=compiler --link /meilisearch/target/release/meilisearch /bin/meilisearch
+COPY    --from=compiler /meilisearch/target/release/meilisearch /bin/meilisearch
 # To stay compatible with the older version of the container (pre v0.27.0) we're
 # going to symlink the meilisearch binary in the path to `/meilisearch`
 RUN     ln -s /bin/meilisearch /meilisearch

assets/prometheus-basic-scraper.yml

@@ -0,0 +1,19 @@
+global:
+  scrape_interval:     15s # By default, scrape targets every 15 seconds.
+
+  # Attach these labels to any time series or alerts when communicating with
+  # external systems (federation, remote storage, Alertmanager).
+  external_labels:
+    monitor: 'codelab-monitor'
+
+# A scrape configuration containing exactly one endpoint to scrape:
+# Here it's Prometheus itself.
+scrape_configs:
+  # The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.
+  - job_name: 'meilisearch'
+
+    # Override the global default and scrape targets from this job every 5 seconds.
+    scrape_interval: 5s
+
+    static_configs:
+      - targets: ['localhost:7700']

config.toml

@@ -1,128 +1,131 @@
 # This file shows the default configuration of Meilisearch.
 # All variables are defined here: https://www.meilisearch.com/docs/learn/configuration/instance_options#environment-variables
 
-db_path = "./data.ms"
 # Designates the location where database files will be created and retrieved.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#database-path
+db_path = "./data.ms"
 
-env = "development"
 # Configures the instance's environment. Value must be either `production` or `development`.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#environment
+env = "development"
 
-http_addr = "localhost:7700"
 # The address on which the HTTP server will listen.
+http_addr = "localhost:7700"
 
-# master_key = "YOUR_MASTER_KEY_VALUE"
 # Sets the instance's master key, automatically protecting all routes except GET /health.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#master-key
+# master_key = "YOUR_MASTER_KEY_VALUE"
 
-# no_analytics = true
 # Deactivates Meilisearch's built-in telemetry when provided.
 # Meilisearch automatically collects data from all instances that do not opt out using this flag.
 # All gathered data is used solely for the purpose of improving Meilisearch, and can be deleted at any time.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#disable-analytics
+# no_analytics = true
 
-http_payload_size_limit = "100 MB"
 # Sets the maximum size of accepted payloads.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#payload-limit-size
+http_payload_size_limit = "100 MB"
 
-log_level = "INFO"
 # Defines how much detail should be present in Meilisearch's logs.
 # Meilisearch currently supports six log levels, listed in order of increasing verbosity:  `OFF`, `ERROR`, `WARN`, `INFO`, `DEBUG`, `TRACE`
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#log-level
+log_level = "INFO"
 
-# max_indexing_memory = "2 GiB"
 # Sets the maximum amount of RAM Meilisearch can use when indexing.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#max-indexing-memory
+# max_indexing_memory = "2 GiB"
 
-# max_indexing_threads = 4
 # Sets the maximum number of threads Meilisearch can use during indexing.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#max-indexing-threads
+# max_indexing_threads = 4
 
 #############
 ### DUMPS ###
 #############
 
-dump_dir = "dumps/"
 # Sets the directory where Meilisearch will create dump files.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#dump-directory
+dump_dir = "dumps/"
 
-# import_dump = "./path/to/my/file.dump"
 # Imports the dump file located at the specified path. Path must point to a .dump file.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#import-dump
+# import_dump = "./path/to/my/file.dump"
 
-ignore_missing_dump = false
 # Prevents Meilisearch from throwing an error when `import_dump` does not point to a valid dump file.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#ignore-missing-dump
+ignore_missing_dump = false
 
-ignore_dump_if_db_exists = false
 # Prevents a Meilisearch instance with an existing database from throwing an error when using `import_dump`.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#ignore-dump-if-db-exists
+ignore_dump_if_db_exists = false
 
 
 #################
 ### SNAPSHOTS ###
 #################
 
-schedule_snapshot = false
 # Enables scheduled snapshots when true, disable when false (the default).
 # If the value is given as an integer, then enables the scheduled snapshot with the passed value as the interval
 # between each snapshot, in seconds.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#schedule-snapshot-creation
+schedule_snapshot = false
 
-snapshot_dir = "snapshots/"
 # Sets the directory where Meilisearch will store snapshots.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#snapshot-destination
+snapshot_dir = "snapshots/"
 
-# import_snapshot = "./path/to/my/snapshot"
 # Launches Meilisearch after importing a previously-generated snapshot at the given filepath.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#import-snapshot
+# import_snapshot = "./path/to/my/snapshot"
 
-ignore_missing_snapshot = false
 # Prevents a Meilisearch instance from throwing an error when `import_snapshot` does not point to a valid snapshot file.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#ignore-missing-snapshot
+ignore_missing_snapshot = false
 
-ignore_snapshot_if_db_exists = false
 # Prevents a Meilisearch instance with an existing database from throwing an error when using `import_snapshot`.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#ignore-snapshot-if-db-exists
+ignore_snapshot_if_db_exists = false
 
 
 ###########
 ### SSL ###
 ###########
 
-# ssl_auth_path = "./path/to/root"
 # Enables client authentication in the specified path.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#ssl-authentication-path
+# ssl_auth_path = "./path/to/root"
 
-# ssl_cert_path = "./path/to/certfile"
 # Sets the server's SSL certificates.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#ssl-certificates-path
+# ssl_cert_path = "./path/to/certfile"
 
-# ssl_key_path = "./path/to/private-key"
 # Sets the server's SSL key files.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#ssl-key-path
+# ssl_key_path = "./path/to/private-key"
 
-# ssl_ocsp_path = "./path/to/ocsp-file"
 # Sets the server's OCSP file.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#ssl-ocsp-path
+# ssl_ocsp_path = "./path/to/ocsp-file"
 
-ssl_require_auth = false
 # Makes SSL authentication mandatory.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#ssl-require-auth
+ssl_require_auth = false
 
-ssl_resumption = false
 # Activates SSL session resumption.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#ssl-resumption
+ssl_resumption = false
 
-ssl_tickets = false
 # Activates SSL tickets.
 # https://www.meilisearch.com/docs/learn/configuration/instance_options#ssl-tickets
+ssl_tickets = false
 
 #############################
 ### Experimental features ###
 #############################
 
-experimental_enable_metrics = false
 # Experimental metrics feature. For more information, see: <https://github.com/meilisearch/meilisearch/discussions/3518>
 # Enables the Prometheus metrics on the `GET /metrics` endpoint.
+experimental_enable_metrics = false
+
+# Experimental RAM reduction during indexing, do not use in production, see: <https://github.com/meilisearch/product/discussions/652>
+experimental_reduce_indexing_memory_usage = false

fuzzers/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "fuzzers"
+publish = false
+
+version.workspace = true
+authors.workspace = true
+description.workspace = true
+homepage.workspace = true
+readme.workspace = true
+edition.workspace = true
+license.workspace = true
+
+[dependencies]
+arbitrary = { version = "1.3.0", features = ["derive"] }
+clap = { version = "4.3.0", features = ["derive"] }
+fastrand = "1.9.0"
+milli = { path = "../milli" }
+serde = { version = "1.0.160", features = ["derive"] }
+serde_json = { version = "1.0.95", features = ["preserve_order"] }
+tempfile = "3.5.0"

fuzzers/README.md

@@ -0,0 +1,3 @@
+# Fuzzers
+
+The purpose of this crate is to contains all the handmade "fuzzer" we may need.

fuzzers/src/bin/fuzz-indexing.rs

@@ -0,0 +1,152 @@
+use std::num::NonZeroUsize;
+use std::path::PathBuf;
+use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
+use std::time::Duration;
+
+use arbitrary::{Arbitrary, Unstructured};
+use clap::Parser;
+use fuzzers::Operation;
+use milli::heed::EnvOpenOptions;
+use milli::update::{IndexDocuments, IndexDocumentsConfig, IndexerConfig};
+use milli::Index;
+use tempfile::TempDir;
+
+#[derive(Debug, Arbitrary)]
+struct Batch([Operation; 5]);
+
+#[derive(Debug, Clone, Parser)]
+struct Opt {
+    /// The number of fuzzer to run in parallel.
+    #[clap(long)]
+    par: Option<NonZeroUsize>,
+    // We need to put a lot of newlines in the following documentation or else everything gets collapsed on one line
+    /// The path in which the databases will be created.
+    /// Using a ramdisk is recommended.
+    ///
+    /// Linux:
+    ///
+    /// sudo mount -t tmpfs -o size=2g tmpfs ramdisk # to create it
+    ///
+    /// sudo umount ramdisk # to remove it
+    ///
+    /// MacOS:
+    ///
+    /// diskutil erasevolume HFS+ 'RAM Disk' `hdiutil attach -nobrowse -nomount ram://4194304 # create it
+    ///
+    /// hdiutil detach /dev/:the_disk
+    #[clap(long)]
+    path: Option<PathBuf>,
+}
+
+fn main() {
+    let opt = Opt::parse();
+    let progression: &'static AtomicUsize = Box::leak(Box::new(AtomicUsize::new(0)));
+    let stop: &'static AtomicBool = Box::leak(Box::new(AtomicBool::new(false)));
+
+    let par = opt.par.unwrap_or_else(|| std::thread::available_parallelism().unwrap()).get();
+    let mut handles = Vec::with_capacity(par);
+
+    for _ in 0..par {
+        let opt = opt.clone();
+
+        let handle = std::thread::spawn(move || {
+            let mut options = EnvOpenOptions::new();
+            options.map_size(1024 * 1024 * 1024 * 1024);
+            let tempdir = match opt.path {
+                Some(path) => TempDir::new_in(path).unwrap(),
+                None => TempDir::new().unwrap(),
+            };
+            let index = Index::new(options, tempdir.path()).unwrap();
+            let indexer_config = IndexerConfig::default();
+            let index_documents_config = IndexDocumentsConfig::default();
+
+            std::thread::scope(|s| {
+                loop {
+                    if stop.load(Ordering::Relaxed) {
+                        return;
+                    }
+                    let v: Vec<u8> =
+                        std::iter::repeat_with(|| fastrand::u8(..)).take(1000).collect();
+
+                    let mut data = Unstructured::new(&v);
+                    let batches = <[Batch; 5]>::arbitrary(&mut data).unwrap();
+                    // will be used to display the error once a thread crashes
+                    let dbg_input = format!("{:#?}", batches);
+
+                    let handle = s.spawn(|| {
+                        let mut wtxn = index.write_txn().unwrap();
+
+                        for batch in batches {
+                            let mut builder = IndexDocuments::new(
+                                &mut wtxn,
+                                &index,
+                                &indexer_config,
+                                index_documents_config.clone(),
+                                |_| (),
+                                || false,
+                            )
+                            .unwrap();
+
+                            for op in batch.0 {
+                                match op {
+                                    Operation::AddDoc(doc) => {
+                                        let documents =
+                                            milli::documents::objects_from_json_value(doc.to_d());
+                                        let documents =
+                                            milli::documents::documents_batch_reader_from_objects(
+                                                documents,
+                                            );
+                                        let (b, _added) = builder.add_documents(documents).unwrap();
+                                        builder = b;
+                                    }
+                                    Operation::DeleteDoc(id) => {
+                                        let (b, _removed) =
+                                            builder.remove_documents(vec![id.to_s()]).unwrap();
+                                        builder = b;
+                                    }
+                                }
+                            }
+                            builder.execute().unwrap();
+
+                            // after executing a batch we check if the database is corrupted
+                            let res = index.search(&wtxn).execute().unwrap();
+                            index.documents(&wtxn, res.documents_ids).unwrap();
+                            progression.fetch_add(1, Ordering::Relaxed);
+                        }
+                        wtxn.abort().unwrap();
+                    });
+                    if let err @ Err(_) = handle.join() {
+                        stop.store(true, Ordering::Relaxed);
+                        err.expect(&dbg_input);
+                    }
+                }
+            });
+        });
+        handles.push(handle);
+    }
+
+    std::thread::spawn(|| {
+        let mut last_value = 0;
+        let start = std::time::Instant::now();
+        loop {
+            let total = progression.load(Ordering::Relaxed);
+            let elapsed = start.elapsed().as_secs();
+            if elapsed > 3600 {
+                // after 1 hour, stop the fuzzer, success
+                std::process::exit(0);
+            }
+            println!(
+                "Has been running for {:?} seconds. Tested {} new values for a total of {}.",
+                elapsed,
+                total - last_value,
+                total
+            );
+            last_value = total;
+            std::thread::sleep(Duration::from_secs(1));
+        }
+    });
+
+    for handle in handles {
+        handle.join().unwrap();
+    }
+}

fuzzers/src/lib.rs

@@ -0,0 +1,46 @@
+use arbitrary::Arbitrary;
+use serde_json::{json, Value};
+
+#[derive(Debug, Arbitrary)]
+pub enum Document {
+    One,
+    Two,
+    Three,
+    Four,
+    Five,
+    Six,
+}
+
+impl Document {
+    pub fn to_d(&self) -> Value {
+        match self {
+            Document::One => json!({ "id": 0, "doggo": "bernese" }),
+            Document::Two => json!({ "id": 0, "doggo": "golden" }),
+            Document::Three => json!({ "id": 0, "catto": "jorts" }),
+            Document::Four => json!({ "id": 1, "doggo": "bernese" }),
+            Document::Five => json!({ "id": 1, "doggo": "golden" }),
+            Document::Six => json!({ "id": 1, "catto": "jorts" }),
+        }
+    }
+}
+
+#[derive(Debug, Arbitrary)]
+pub enum DocId {
+    Zero,
+    One,
+}
+
+impl DocId {
+    pub fn to_s(&self) -> String {
+        match self {
+            DocId::Zero => "0".to_string(),
+            DocId::One => "1".to_string(),
+        }
+    }
+}
+
+#[derive(Debug, Arbitrary)]
+pub enum Operation {
+    AddDoc(Document),
+    DeleteDoc(DocId),
+}

index-scheduler/src/autobatcher.rs

@@ -321,9 +321,18 @@ impl BatchKind {
                 })
             }
             (
-                this @ BatchKind::DocumentOperation { .. },
+                BatchKind::DocumentOperation { method, allow_index_creation, primary_key, mut operation_ids },
                 K::DocumentDeletion,
-            ) => Break(this),
+            ) => {
+                operation_ids.push(id);
+
+                Continue(BatchKind::DocumentOperation {
+                    method,
+                    allow_index_creation,
+                    primary_key,
+                    operation_ids,
+                })
+            }
             // but we can't autobatch documents if it's not the same kind
             // this match branch MUST be AFTER the previous one
             (
@@ -346,7 +355,35 @@ impl BatchKind {
                 deletion_ids.push(id);
                 Continue(BatchKind::DocumentClear { ids: deletion_ids })
             }
-            // we can't autobatch a deletion and an import
+            // we can autobatch the deletion and import if the index already exists
+            (
+                BatchKind::DocumentDeletion { mut deletion_ids },
+                K::DocumentImport { method, allow_index_creation, primary_key }
+            ) if index_already_exists => {
+                deletion_ids.push(id);
+
+                Continue(BatchKind::DocumentOperation {
+                    method,
+                    allow_index_creation,
+                    primary_key,
+                    operation_ids: deletion_ids,
+                })
+            }
+            // we can autobatch the deletion and import if both can't create an index
+            (
+                BatchKind::DocumentDeletion { mut deletion_ids },
+                K::DocumentImport { method, allow_index_creation, primary_key }
+            ) if !allow_index_creation => {
+                deletion_ids.push(id);
+
+                Continue(BatchKind::DocumentOperation {
+                    method,
+                    allow_index_creation,
+                    primary_key,
+                    operation_ids: deletion_ids,
+                })
+            }
+            // we can't autobatch a deletion and an import if the index does not exists but would be created by an addition
             (
                 this @ BatchKind::DocumentDeletion { .. },
                 K::DocumentImport { .. }
@@ -648,36 +685,36 @@ mod tests {
         debug_snapshot!(autobatch_from(false,None,  [settings(false)]), @"Some((Settings { allow_index_creation: false, settings_ids: [0] }, false))");
         debug_snapshot!(autobatch_from(false,None,  [settings(false), settings(false), settings(false)]), @"Some((Settings { allow_index_creation: false, settings_ids: [0, 1, 2] }, false))");
 
-        // We can't autobatch document addition with document deletion
+        // We can autobatch document addition with document deletion
-        debug_snapshot!(autobatch_from(true, None, [doc_imp(ReplaceDocuments, true, None), doc_del()]), @"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: true, primary_key: None, operation_ids: [0] }, true))");
+        debug_snapshot!(autobatch_from(true, None, [doc_imp(ReplaceDocuments, true, None), doc_del()]), @"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: true, primary_key: None, operation_ids: [0, 1] }, true))");
-        debug_snapshot!(autobatch_from(true, None, [doc_imp(UpdateDocuments, true, None), doc_del()]), @"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: true, primary_key: None, operation_ids: [0] }, true))");
+        debug_snapshot!(autobatch_from(true, None, [doc_imp(UpdateDocuments, true, None), doc_del()]), @"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: true, primary_key: None, operation_ids: [0, 1] }, true))");
-        debug_snapshot!(autobatch_from(true, None, [doc_imp(ReplaceDocuments, false, None), doc_del()]), @"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(true, None, [doc_imp(ReplaceDocuments, false, None), doc_del()]), @"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0, 1] }, false))");
-        debug_snapshot!(autobatch_from(true, None, [doc_imp(UpdateDocuments, false, None), doc_del()]), @"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(true, None, [doc_imp(UpdateDocuments, false, None), doc_del()]), @"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0, 1] }, false))");
-        debug_snapshot!(autobatch_from(true, None, [doc_imp(ReplaceDocuments, true, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: true, primary_key: Some("catto"), operation_ids: [0] }, true))"###);
+        debug_snapshot!(autobatch_from(true, None, [doc_imp(ReplaceDocuments, true, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: true, primary_key: Some("catto"), operation_ids: [0, 1] }, true))"###);
-        debug_snapshot!(autobatch_from(true, None, [doc_imp(UpdateDocuments, true, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: true, primary_key: Some("catto"), operation_ids: [0] }, true))"###);
+        debug_snapshot!(autobatch_from(true, None, [doc_imp(UpdateDocuments, true, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: true, primary_key: Some("catto"), operation_ids: [0, 1] }, true))"###);
-        debug_snapshot!(autobatch_from(true, None, [doc_imp(ReplaceDocuments, false, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0] }, false))"###);
+        debug_snapshot!(autobatch_from(true, None, [doc_imp(ReplaceDocuments, false, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0, 1] }, false))"###);
-        debug_snapshot!(autobatch_from(true, None, [doc_imp(UpdateDocuments, false, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0] }, false))"###);
+        debug_snapshot!(autobatch_from(true, None, [doc_imp(UpdateDocuments, false, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0, 1] }, false))"###);
-        debug_snapshot!(autobatch_from(false, None, [doc_imp(ReplaceDocuments, true, None), doc_del()]), @"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: true, primary_key: None, operation_ids: [0] }, true))");
+        debug_snapshot!(autobatch_from(false, None, [doc_imp(ReplaceDocuments, true, None), doc_del()]), @"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: true, primary_key: None, operation_ids: [0, 1] }, true))");
-        debug_snapshot!(autobatch_from(false, None, [doc_imp(UpdateDocuments, true, None), doc_del()]), @"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: true, primary_key: None, operation_ids: [0] }, true))");
+        debug_snapshot!(autobatch_from(false, None, [doc_imp(UpdateDocuments, true, None), doc_del()]), @"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: true, primary_key: None, operation_ids: [0, 1] }, true))");
-        debug_snapshot!(autobatch_from(false, None, [doc_imp(ReplaceDocuments, false, None), doc_del()]), @"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(false, None, [doc_imp(ReplaceDocuments, false, None), doc_del()]), @"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0, 1] }, false))");
-        debug_snapshot!(autobatch_from(false, None, [doc_imp(UpdateDocuments, false, None), doc_del()]), @"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(false, None, [doc_imp(UpdateDocuments, false, None), doc_del()]), @"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0, 1] }, false))");
-        debug_snapshot!(autobatch_from(false, None, [doc_imp(ReplaceDocuments, true, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: true, primary_key: Some("catto"), operation_ids: [0] }, true))"###);
+        debug_snapshot!(autobatch_from(false, None, [doc_imp(ReplaceDocuments, true, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: true, primary_key: Some("catto"), operation_ids: [0, 1] }, true))"###);
-        debug_snapshot!(autobatch_from(false, None, [doc_imp(UpdateDocuments, true, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: true, primary_key: Some("catto"), operation_ids: [0] }, true))"###);
+        debug_snapshot!(autobatch_from(false, None, [doc_imp(UpdateDocuments, true, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: true, primary_key: Some("catto"), operation_ids: [0, 1] }, true))"###);
-        debug_snapshot!(autobatch_from(false, None, [doc_imp(ReplaceDocuments, false, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0] }, false))"###);
+        debug_snapshot!(autobatch_from(false, None, [doc_imp(ReplaceDocuments, false, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0, 1] }, false))"###);
-        debug_snapshot!(autobatch_from(false, None, [doc_imp(UpdateDocuments, false, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0] }, false))"###);
+        debug_snapshot!(autobatch_from(false, None, [doc_imp(UpdateDocuments, false, Some("catto")), doc_del()]), @r###"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0, 1] }, false))"###);
-        // we also can't do the only way around
+        // And the other way around
-        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(ReplaceDocuments, true, None)]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(ReplaceDocuments, true, None)]), @"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: true, primary_key: None, operation_ids: [0, 1] }, false))");
-        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(UpdateDocuments, true, None)]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(UpdateDocuments, true, None)]), @"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: true, primary_key: None, operation_ids: [0, 1] }, false))");
-        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(ReplaceDocuments, false, None)]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(ReplaceDocuments, false, None)]), @"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0, 1] }, false))");
-        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(UpdateDocuments, false, None)]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(UpdateDocuments, false, None)]), @"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0, 1] }, false))");
-        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(ReplaceDocuments, true, Some("catto"))]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(ReplaceDocuments, true, Some("catto"))]), @r###"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: true, primary_key: Some("catto"), operation_ids: [0, 1] }, false))"###);
-        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(UpdateDocuments, true, Some("catto"))]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(UpdateDocuments, true, Some("catto"))]), @r###"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: true, primary_key: Some("catto"), operation_ids: [0, 1] }, false))"###);
-        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(ReplaceDocuments, false, Some("catto"))]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(ReplaceDocuments, false, Some("catto"))]), @r###"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0, 1] }, false))"###);
-        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(UpdateDocuments, false, Some("catto"))]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(true, None, [doc_del(), doc_imp(UpdateDocuments, false, Some("catto"))]), @r###"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0, 1] }, false))"###);
-        debug_snapshot!(autobatch_from(false, None, [doc_del(), doc_imp(ReplaceDocuments, false, None)]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(false, None, [doc_del(), doc_imp(ReplaceDocuments, false, None)]), @"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0, 1] }, false))");
-        debug_snapshot!(autobatch_from(false, None, [doc_del(), doc_imp(UpdateDocuments, false, None)]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(false, None, [doc_del(), doc_imp(UpdateDocuments, false, None)]), @"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: None, operation_ids: [0, 1] }, false))");
-        debug_snapshot!(autobatch_from(false, None, [doc_del(), doc_imp(ReplaceDocuments, false, Some("catto"))]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(false, None, [doc_del(), doc_imp(ReplaceDocuments, false, Some("catto"))]), @r###"Some((DocumentOperation { method: ReplaceDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0, 1] }, false))"###);
-        debug_snapshot!(autobatch_from(false, None, [doc_del(), doc_imp(UpdateDocuments, false, Some("catto"))]), @"Some((DocumentDeletion { deletion_ids: [0] }, false))");
+        debug_snapshot!(autobatch_from(false, None, [doc_del(), doc_imp(UpdateDocuments, false, Some("catto"))]), @r###"Some((DocumentOperation { method: UpdateDocuments, allow_index_creation: false, primary_key: Some("catto"), operation_ids: [0, 1] }, false))"###);
     }
 
     #[test]

index-scheduler/src/batch.rs

@@ -24,6 +24,7 @@ use std::io::BufWriter;
 
 use dump::IndexMetadata;
 use log::{debug, error, info};
+use meilisearch_types::error::Code;
 use meilisearch_types::heed::{RoTxn, RwTxn};
 use meilisearch_types::milli::documents::{obkv_to_object, DocumentsBatchReader};
 use meilisearch_types::milli::heed::CompactionOption;
@@ -1491,7 +1492,12 @@ fn delete_document_by_filter(filter: &serde_json::Value, index: Index) -> Result
     Ok(if let Some(filter) = filter {
         let mut wtxn = index.write_txn()?;
 
-        let candidates = filter.evaluate(&wtxn, &index)?;
+        let candidates = filter.evaluate(&wtxn, &index).map_err(|err| match err {
+            milli::Error::UserError(milli::UserError::InvalidFilter(_)) => {
+                Error::from(err).with_custom_error_code(Code::InvalidDocumentFilter)
+            }
+            e => e.into(),
+        })?;
         let mut delete_operation = DeleteDocuments::new(&mut wtxn, &index)?;
         delete_operation.delete_documents(&candidates);
         let deleted_documents =

index-scheduler/src/error.rs

@@ -46,6 +46,8 @@ impl From<DateField> for Code {
 #[allow(clippy::large_enum_variant)]
 #[derive(Error, Debug)]
 pub enum Error {
+    #[error("{1}")]
+    WithCustomErrorCode(Code, Box<Self>),
     #[error("Index `{0}` not found.")]
     IndexNotFound(String),
     #[error("Index `{0}` already exists.")]
@@ -144,6 +146,7 @@ impl Error {
     pub fn is_recoverable(&self) -> bool {
         match self {
             Error::IndexNotFound(_)
+            | Error::WithCustomErrorCode(_, _)
             | Error::IndexAlreadyExists(_)
             | Error::SwapDuplicateIndexFound(_)
             | Error::SwapDuplicateIndexesFound(_)
@@ -176,11 +179,16 @@ impl Error {
             Error::PlannedFailure => false,
         }
     }
+
+    pub fn with_custom_error_code(self, code: Code) -> Self {
+        Self::WithCustomErrorCode(code, Box::new(self))
+    }
 }
 
 impl ErrorCode for Error {
     fn error_code(&self) -> Code {
         match self {
+            Error::WithCustomErrorCode(code, _) => *code,
             Error::IndexNotFound(_) => Code::IndexNotFound,
             Error::IndexAlreadyExists(_) => Code::IndexAlreadyExists,
             Error::SwapDuplicateIndexesFound(_) => Code::InvalidSwapDuplicateIndexFound,

index-scheduler/src/index_mapper/index_map.rs

@@ -5,6 +5,7 @@ use std::collections::BTreeMap;
 use std::path::Path;
 use std::time::Duration;
 
+use meilisearch_types::heed::flags::Flags;
 use meilisearch_types::heed::{EnvClosingEvent, EnvOpenOptions};
 use meilisearch_types::milli::Index;
 use time::OffsetDateTime;
@@ -53,6 +54,7 @@ pub struct IndexMap {
 pub struct ClosingIndex {
     uuid: Uuid,
     closing_event: EnvClosingEvent,
+    enable_mdb_writemap: bool,
     map_size: usize,
     generation: usize,
 }
@@ -68,6 +70,7 @@ impl ClosingIndex {
     pub fn wait_timeout(self, timeout: Duration) -> Option<ReopenableIndex> {
         self.closing_event.wait_timeout(timeout).then_some(ReopenableIndex {
             uuid: self.uuid,
+            enable_mdb_writemap: self.enable_mdb_writemap,
             map_size: self.map_size,
             generation: self.generation,
         })
@@ -76,6 +79,7 @@ impl ClosingIndex {
 
 pub struct ReopenableIndex {
     uuid: Uuid,
+    enable_mdb_writemap: bool,
     map_size: usize,
     generation: usize,
 }
@@ -103,7 +107,7 @@ impl ReopenableIndex {
                 return Ok(());
             }
             map.unavailable.remove(&self.uuid);
-            map.create(&self.uuid, path, None, self.map_size)?;
+            map.create(&self.uuid, path, None, self.enable_mdb_writemap, self.map_size)?;
         }
         Ok(())
     }
@@ -170,16 +174,17 @@ impl IndexMap {
         uuid: &Uuid,
         path: &Path,
         date: Option<(OffsetDateTime, OffsetDateTime)>,
+        enable_mdb_writemap: bool,
         map_size: usize,
     ) -> Result<Index> {
         if !matches!(self.get_unavailable(uuid), Missing) {
             panic!("Attempt to open an index that was unavailable");
         }
-        let index = create_or_open_index(path, date, map_size)?;
+        let index = create_or_open_index(path, date, enable_mdb_writemap, map_size)?;
         match self.available.insert(*uuid, index.clone()) {
             InsertionOutcome::InsertedNew => (),
             InsertionOutcome::Evicted(evicted_uuid, evicted_index) => {
-                self.close(evicted_uuid, evicted_index, 0);
+                self.close(evicted_uuid, evicted_index, enable_mdb_writemap, 0);
             }
             InsertionOutcome::Replaced(_) => {
                 panic!("Attempt to open an index that was already opened")
@@ -212,17 +217,30 @@ impl IndexMap {
     /// | Closing         | Closing       |
     /// | Available       | Closing       |
     ///
-    pub fn close_for_resize(&mut self, uuid: &Uuid, map_size_growth: usize) {
+    pub fn close_for_resize(
+        &mut self,
+        uuid: &Uuid,
+        enable_mdb_writemap: bool,
+        map_size_growth: usize,
+    ) {
         let Some(index) = self.available.remove(uuid) else { return; };
-        self.close(*uuid, index, map_size_growth);
+        self.close(*uuid, index, enable_mdb_writemap, map_size_growth);
     }
 
-    fn close(&mut self, uuid: Uuid, index: Index, map_size_growth: usize) {
+    fn close(
+        &mut self,
+        uuid: Uuid,
+        index: Index,
+        enable_mdb_writemap: bool,
+        map_size_growth: usize,
+    ) {
         let map_size = index.map_size().unwrap_or(DEFAULT_MAP_SIZE) + map_size_growth;
         let closing_event = index.prepare_for_closing();
         let generation = self.next_generation();
-        self.unavailable
+        self.unavailable.insert(
-            .insert(uuid, Some(ClosingIndex { uuid, closing_event, map_size, generation }));
+            uuid,
+            Some(ClosingIndex { uuid, closing_event, enable_mdb_writemap, map_size, generation }),
+        );
     }
 
     /// Attempts to delete and index.
@@ -282,11 +300,15 @@ impl IndexMap {
 fn create_or_open_index(
     path: &Path,
     date: Option<(OffsetDateTime, OffsetDateTime)>,
+    enable_mdb_writemap: bool,
     map_size: usize,
 ) -> Result<Index> {
     let mut options = EnvOpenOptions::new();
     options.map_size(clamp_to_page_size(map_size));
     options.max_readers(1024);
+    if enable_mdb_writemap {
+        unsafe { options.flag(Flags::MdbWriteMap) };
+    }
 
     if let Some((created, updated)) = date {
         Ok(Index::new_with_creation_dates(options, path, created, updated)?)

index-scheduler/src/index_mapper/mod.rs

@@ -66,6 +66,8 @@ pub struct IndexMapper {
     index_base_map_size: usize,
     /// The quantity by which the map size of an index is incremented upon reopening, in bytes.
     index_growth_amount: usize,
+    /// Whether we open a meilisearch index with the MDB_WRITEMAP option or not.
+    enable_mdb_writemap: bool,
     pub indexer_config: Arc<IndexerConfig>,
 }
 
@@ -88,8 +90,17 @@ pub enum IndexStatus {
 pub struct IndexStats {
     /// Number of documents in the index.
     pub number_of_documents: u64,
-    /// Size of the index' DB, in bytes.
+    /// Size taken up by the index' DB, in bytes.
+    ///
+    /// This includes the size taken by both the used and free pages of the DB, and as the free pages
+    /// are not returned to the disk after a deletion, this number is typically larger than
+    /// `used_database_size` that only includes the size of the used pages.
     pub database_size: u64,
+    /// Size taken by the used pages of the index' DB, in bytes.
+    ///
+    /// As the DB backend does not return to the disk the pages that are not currently used by the DB,
+    /// this value is typically smaller than `database_size`.
+    pub used_database_size: u64,
     /// Association of every field name with the number of times it occurs in the documents.
     pub field_distribution: FieldDistribution,
     /// Creation date of the index.
@@ -105,10 +116,10 @@ impl IndexStats {
     ///
     /// - rtxn: a RO transaction for the index, obtained from `Index::read_txn()`.
     pub fn new(index: &Index, rtxn: &RoTxn) -> Result<Self> {
-        let database_size = index.on_disk_size()?;
         Ok(IndexStats {
             number_of_documents: index.number_of_documents(rtxn)?,
-            database_size,
+            database_size: index.on_disk_size()?,
+            used_database_size: index.used_size()?,
             field_distribution: index.field_distribution(rtxn)?,
             created_at: index.created_at(rtxn)?,
             updated_at: index.updated_at(rtxn)?,
@@ -123,15 +134,22 @@ impl IndexMapper {
         index_base_map_size: usize,
         index_growth_amount: usize,
         index_count: usize,
+        enable_mdb_writemap: bool,
         indexer_config: IndexerConfig,
     ) -> Result<Self> {
+        let mut wtxn = env.write_txn()?;
+        let index_mapping = env.create_database(&mut wtxn, Some(INDEX_MAPPING))?;
+        let index_stats = env.create_database(&mut wtxn, Some(INDEX_STATS))?;
+        wtxn.commit()?;
+
         Ok(Self {
             index_map: Arc::new(RwLock::new(IndexMap::new(index_count))),
-            index_mapping: env.create_database(Some(INDEX_MAPPING))?,
+            index_mapping,
-            index_stats: env.create_database(Some(INDEX_STATS))?,
+            index_stats,
             base_path,
             index_base_map_size,
             index_growth_amount,
+            enable_mdb_writemap,
             indexer_config: Arc::new(indexer_config),
         })
     }
@@ -162,6 +180,7 @@ impl IndexMapper {
                     &uuid,
                     &index_path,
                     date,
+                    self.enable_mdb_writemap,
                     self.index_base_map_size,
                 )?;
 
@@ -273,7 +292,11 @@ impl IndexMapper {
             .ok_or_else(|| Error::IndexNotFound(name.to_string()))?;
 
         // We remove the index from the in-memory index map.
-        self.index_map.write().unwrap().close_for_resize(&uuid, self.index_growth_amount);
+        self.index_map.write().unwrap().close_for_resize(
+            &uuid,
+            self.enable_mdb_writemap,
+            self.index_growth_amount,
+        );
 
         Ok(())
     }
@@ -338,6 +361,7 @@ impl IndexMapper {
                                 &uuid,
                                 &index_path,
                                 None,
+                                self.enable_mdb_writemap,
                                 self.index_base_map_size,
                             )?;
                         }

index-scheduler/src/lib.rs

@@ -31,7 +31,7 @@ mod uuid_codec;
 pub type Result<T> = std::result::Result<T, Error>;
 pub type TaskId = u32;
 
-use std::collections::HashMap;
+use std::collections::{BTreeMap, HashMap};
 use std::ops::{Bound, RangeBounds};
 use std::path::{Path, PathBuf};
 use std::sync::atomic::AtomicBool;
@@ -233,6 +233,8 @@ pub struct IndexSchedulerOptions {
     pub task_db_size: usize,
     /// The size, in bytes, with which a meilisearch index is opened the first time of each meilisearch index.
     pub index_base_map_size: usize,
+    /// Whether we open a meilisearch index with the MDB_WRITEMAP option or not.
+    pub enable_mdb_writemap: bool,
     /// The size, in bytes, by which the map size of an index is increased when it resized due to being full.
     pub index_growth_amount: usize,
     /// The number of indexes that can be concurrently opened in memory.
@@ -374,6 +376,11 @@ impl IndexScheduler {
         std::fs::create_dir_all(&options.indexes_path)?;
         std::fs::create_dir_all(&options.dumps_path)?;
 
+        if cfg!(windows) && options.enable_mdb_writemap {
+            // programmer error if this happens: in normal use passing the option on Windows is an error in main
+            panic!("Windows doesn't support the MDB_WRITEMAP LMDB option");
+        }
+
         let task_db_size = clamp_to_page_size(options.task_db_size);
         let budget = if options.indexer_config.skip_index_budget {
             IndexBudget {
@@ -396,25 +403,37 @@ impl IndexScheduler {
             .open(options.tasks_path)?;
         let file_store = FileStore::new(&options.update_file_path)?;
 
+        let mut wtxn = env.write_txn()?;
+        let all_tasks = env.create_database(&mut wtxn, Some(db_name::ALL_TASKS))?;
+        let status = env.create_database(&mut wtxn, Some(db_name::STATUS))?;
+        let kind = env.create_database(&mut wtxn, Some(db_name::KIND))?;
+        let index_tasks = env.create_database(&mut wtxn, Some(db_name::INDEX_TASKS))?;
+        let canceled_by = env.create_database(&mut wtxn, Some(db_name::CANCELED_BY))?;
+        let enqueued_at = env.create_database(&mut wtxn, Some(db_name::ENQUEUED_AT))?;
+        let started_at = env.create_database(&mut wtxn, Some(db_name::STARTED_AT))?;
+        let finished_at = env.create_database(&mut wtxn, Some(db_name::FINISHED_AT))?;
+        wtxn.commit()?;
+
         // allow unreachable_code to get rids of the warning in the case of a test build.
         let this = Self {
             must_stop_processing: MustStopProcessing::default(),
             processing_tasks: Arc::new(RwLock::new(ProcessingTasks::new())),
             file_store,
-            all_tasks: env.create_database(Some(db_name::ALL_TASKS))?,
+            all_tasks,
-            status: env.create_database(Some(db_name::STATUS))?,
+            status,
-            kind: env.create_database(Some(db_name::KIND))?,
+            kind,
-            index_tasks: env.create_database(Some(db_name::INDEX_TASKS))?,
+            index_tasks,
-            canceled_by: env.create_database(Some(db_name::CANCELED_BY))?,
+            canceled_by,
-            enqueued_at: env.create_database(Some(db_name::ENQUEUED_AT))?,
+            enqueued_at,
-            started_at: env.create_database(Some(db_name::STARTED_AT))?,
+            started_at,
-            finished_at: env.create_database(Some(db_name::FINISHED_AT))?,
+            finished_at,
             index_mapper: IndexMapper::new(
                 &env,
                 options.indexes_path,
                 budget.map_size,
                 options.index_growth_amount,
                 budget.index_count,
+                options.enable_mdb_writemap,
                 options.indexer_config,
             )?,
             env,
@@ -554,10 +573,16 @@ impl IndexScheduler {
         &self.index_mapper.indexer_config
     }
 
+    /// Return the real database size (i.e.: The size **with** the free pages)
     pub fn size(&self) -> Result<u64> {
         Ok(self.env.real_disk_size()?)
     }
 
+    /// Return the used database size (i.e.: The size **without** the free pages)
+    pub fn used_size(&self) -> Result<u64> {
+        Ok(self.env.non_free_pages_size()?)
+    }
+
     /// Return the index corresponding to the name.
     ///
     /// * If the index wasn't opened before, the index will be opened.
@@ -737,6 +762,38 @@ impl IndexScheduler {
         Ok(tasks)
     }
 
+    /// The returned structure contains:
+    /// 1. The name of the property being observed can be `statuses`, `types`, or `indexes`.
+    /// 2. The name of the specific data related to the property can be `enqueued` for the `statuses`, `settingsUpdate` for the `types`, or the name of the index for the `indexes`, for example.
+    /// 3. The number of times the properties appeared.
+    pub fn get_stats(&self) -> Result<BTreeMap<String, BTreeMap<String, u64>>> {
+        let rtxn = self.read_txn()?;
+
+        let mut res = BTreeMap::new();
+
+        res.insert(
+            "statuses".to_string(),
+            enum_iterator::all::<Status>()
+                .map(|s| Ok((s.to_string(), self.get_status(&rtxn, s)?.len())))
+                .collect::<Result<BTreeMap<String, u64>>>()?,
+        );
+        res.insert(
+            "types".to_string(),
+            enum_iterator::all::<Kind>()
+                .map(|s| Ok((s.to_string(), self.get_kind(&rtxn, s)?.len())))
+                .collect::<Result<BTreeMap<String, u64>>>()?,
+        );
+        res.insert(
+            "indexes".to_string(),
+            self.index_tasks
+                .iter(&rtxn)?
+                .map(|res| Ok(res.map(|(name, bitmap)| (name.to_string(), bitmap.len()))?))
+                .collect::<Result<BTreeMap<String, u64>>>()?,
+        );
+
+        Ok(res)
+    }
+
     /// Return true iff there is at least one task associated with this index
     /// that is processing.
     pub fn is_index_processing(&self, index: &str) -> Result<bool> {
@@ -1471,6 +1528,7 @@ mod tests {
                 dumps_path: tempdir.path().join("dumps"),
                 task_db_size: 1000 * 1000, // 1 MB, we don't use MiB on purpose.
                 index_base_map_size: 1000 * 1000, // 1 MB, we don't use MiB on purpose.
+                enable_mdb_writemap: false,
                 index_growth_amount: 1000 * 1000, // 1 MB
                 index_count: 5,
                 indexer_config,
@@ -2017,6 +2075,105 @@ mod tests {
         snapshot!(snapshot_index_scheduler(&index_scheduler), name: "both_task_succeeded");
     }
 
+    #[test]
+    fn document_addition_and_document_deletion() {
+        let (index_scheduler, mut handle) = IndexScheduler::test(true, vec![]);
+
+        let content = r#"[
+            { "id": 1, "doggo": "jean bob" },
+            { "id": 2, "catto": "jorts" },
+            { "id": 3, "doggo": "bork" }
+        ]"#;
+
+        let (uuid, mut file) = index_scheduler.create_update_file_with_uuid(0).unwrap();
+        let documents_count = read_json(content.as_bytes(), file.as_file_mut()).unwrap();
+        file.persist().unwrap();
+        index_scheduler
+            .register(KindWithContent::DocumentAdditionOrUpdate {
+                index_uid: S("doggos"),
+                primary_key: Some(S("id")),
+                method: ReplaceDocuments,
+                content_file: uuid,
+                documents_count,
+                allow_index_creation: true,
+            })
+            .unwrap();
+        snapshot!(snapshot_index_scheduler(&index_scheduler), name: "registered_the_first_task");
+        index_scheduler
+            .register(KindWithContent::DocumentDeletion {
+                index_uid: S("doggos"),
+                documents_ids: vec![S("1"), S("2")],
+            })
+            .unwrap();
+        snapshot!(snapshot_index_scheduler(&index_scheduler), name: "registered_the_second_task");
+
+        handle.advance_one_successful_batch(); // The addition AND deletion should've been batched together
+        snapshot!(snapshot_index_scheduler(&index_scheduler), name: "after_processing_the_batch");
+
+        let index = index_scheduler.index("doggos").unwrap();
+        let rtxn = index.read_txn().unwrap();
+        let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
+        let field_ids = field_ids_map.ids().collect::<Vec<_>>();
+        let documents = index
+            .all_documents(&rtxn)
+            .unwrap()
+            .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
+            .collect::<Vec<_>>();
+        snapshot!(serde_json::to_string_pretty(&documents).unwrap(), name: "documents");
+    }
+
+    #[test]
+    fn document_deletion_and_document_addition() {
+        let (index_scheduler, mut handle) = IndexScheduler::test(true, vec![]);
+        index_scheduler
+            .register(KindWithContent::DocumentDeletion {
+                index_uid: S("doggos"),
+                documents_ids: vec![S("1"), S("2")],
+            })
+            .unwrap();
+        snapshot!(snapshot_index_scheduler(&index_scheduler), name: "registered_the_first_task");
+
+        let content = r#"[
+            { "id": 1, "doggo": "jean bob" },
+            { "id": 2, "catto": "jorts" },
+            { "id": 3, "doggo": "bork" }
+        ]"#;
+
+        let (uuid, mut file) = index_scheduler.create_update_file_with_uuid(0).unwrap();
+        let documents_count = read_json(content.as_bytes(), file.as_file_mut()).unwrap();
+        file.persist().unwrap();
+        index_scheduler
+            .register(KindWithContent::DocumentAdditionOrUpdate {
+                index_uid: S("doggos"),
+                primary_key: Some(S("id")),
+                method: ReplaceDocuments,
+                content_file: uuid,
+                documents_count,
+                allow_index_creation: true,
+            })
+            .unwrap();
+        snapshot!(snapshot_index_scheduler(&index_scheduler), name: "registered_the_second_task");
+
+        // The deletion should have failed because it can't create an index
+        handle.advance_one_failed_batch();
+        snapshot!(snapshot_index_scheduler(&index_scheduler), name: "after_failing_the_deletion");
+
+        // The addition should works
+        handle.advance_one_successful_batch();
+        snapshot!(snapshot_index_scheduler(&index_scheduler), name: "after_last_successful_addition");
+
+        let index = index_scheduler.index("doggos").unwrap();
+        let rtxn = index.read_txn().unwrap();
+        let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
+        let field_ids = field_ids_map.ids().collect::<Vec<_>>();
+        let documents = index
+            .all_documents(&rtxn)
+            .unwrap()
+            .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
+            .collect::<Vec<_>>();
+        snapshot!(serde_json::to_string_pretty(&documents).unwrap(), name: "documents");
+    }
+
     #[test]
     fn do_not_batch_task_of_different_indexes() {
         let (index_scheduler, mut handle) = IndexScheduler::test(true, vec![]);

index-scheduler/src/snapshots/lib.rs/document_addition_and_document_deletion/after_processing_the_batch.snap

@@ -0,0 +1,43 @@
+---
+source: index-scheduler/src/lib.rs
+---
+### Autobatching Enabled = true
+### Processing Tasks:
+[]
+----------------------------------------------------------------------
+### All Tasks:
+0 {uid: 0, status: succeeded, details: { received_documents: 3, indexed_documents: Some(3) }, kind: DocumentAdditionOrUpdate { index_uid: "doggos", primary_key: Some("id"), method: ReplaceDocuments, content_file: 00000000-0000-0000-0000-000000000000, documents_count: 3, allow_index_creation: true }}
+1 {uid: 1, status: succeeded, details: { received_document_ids: 2, deleted_documents: Some(2) }, kind: DocumentDeletion { index_uid: "doggos", documents_ids: ["1", "2"] }}
+----------------------------------------------------------------------
+### Status:
+enqueued []
+succeeded [0,1,]
+----------------------------------------------------------------------
+### Kind:
+"documentAdditionOrUpdate" [0,]
+"documentDeletion" [1,]
+----------------------------------------------------------------------
+### Index Tasks:
+doggos [0,1,]
+----------------------------------------------------------------------
+### Index Mapper:
+doggos: { number_of_documents: 1, field_distribution: {"doggo": 1, "id": 1} }
+
+----------------------------------------------------------------------
+### Canceled By:
+
+----------------------------------------------------------------------
+### Enqueued At:
+[timestamp] [0,]
+[timestamp] [1,]
+----------------------------------------------------------------------
+### Started At:
+[timestamp] [0,1,]
+----------------------------------------------------------------------
+### Finished At:
+[timestamp] [0,1,]
+----------------------------------------------------------------------
+### File Store:
+
+----------------------------------------------------------------------
+

index-scheduler/src/snapshots/lib.rs/document_addition_and_document_deletion/documents.snap

@@ -0,0 +1,9 @@
+---
+source: index-scheduler/src/lib.rs
+---
+[
+  {
+    "id": 3,
+    "doggo": "bork"
+  }
+]

index-scheduler/src/snapshots/lib.rs/document_addition_and_document_deletion/registered_the_first_task.snap

@@ -0,0 +1,37 @@
+---
+source: index-scheduler/src/lib.rs
+---
+### Autobatching Enabled = true
+### Processing Tasks:
+[]
+----------------------------------------------------------------------
+### All Tasks:
+0 {uid: 0, status: enqueued, details: { received_documents: 3, indexed_documents: None }, kind: DocumentAdditionOrUpdate { index_uid: "doggos", primary_key: Some("id"), method: ReplaceDocuments, content_file: 00000000-0000-0000-0000-000000000000, documents_count: 3, allow_index_creation: true }}
+----------------------------------------------------------------------
+### Status:
+enqueued [0,]
+----------------------------------------------------------------------
+### Kind:
+"documentAdditionOrUpdate" [0,]
+----------------------------------------------------------------------
+### Index Tasks:
+doggos [0,]
+----------------------------------------------------------------------
+### Index Mapper:
+
+----------------------------------------------------------------------
+### Canceled By:
+
+----------------------------------------------------------------------
+### Enqueued At:
+[timestamp] [0,]
+----------------------------------------------------------------------
+### Started At:
+----------------------------------------------------------------------
+### Finished At:
+----------------------------------------------------------------------
+### File Store:
+00000000-0000-0000-0000-000000000000
+
+----------------------------------------------------------------------
+

index-scheduler/src/snapshots/lib.rs/document_addition_and_document_deletion/registered_the_second_task.snap

@@ -0,0 +1,40 @@
+---
+source: index-scheduler/src/lib.rs
+---
+### Autobatching Enabled = true
+### Processing Tasks:
+[]
+----------------------------------------------------------------------
+### All Tasks:
+0 {uid: 0, status: enqueued, details: { received_documents: 3, indexed_documents: None }, kind: DocumentAdditionOrUpdate { index_uid: "doggos", primary_key: Some("id"), method: ReplaceDocuments, content_file: 00000000-0000-0000-0000-000000000000, documents_count: 3, allow_index_creation: true }}
+1 {uid: 1, status: enqueued, details: { received_document_ids: 2, deleted_documents: None }, kind: DocumentDeletion { index_uid: "doggos", documents_ids: ["1", "2"] }}
+----------------------------------------------------------------------
+### Status:
+enqueued [0,1,]
+----------------------------------------------------------------------
+### Kind:
+"documentAdditionOrUpdate" [0,]
+"documentDeletion" [1,]
+----------------------------------------------------------------------
+### Index Tasks:
+doggos [0,1,]
+----------------------------------------------------------------------
+### Index Mapper:
+
+----------------------------------------------------------------------
+### Canceled By:
+
+----------------------------------------------------------------------
+### Enqueued At:
+[timestamp] [0,]
+[timestamp] [1,]
+----------------------------------------------------------------------
+### Started At:
+----------------------------------------------------------------------
+### Finished At:
+----------------------------------------------------------------------
+### File Store:
+00000000-0000-0000-0000-000000000000
+
+----------------------------------------------------------------------
+

index-scheduler/src/snapshots/lib.rs/document_deletion_and_document_addition/after_failing_the_deletion.snap

@@ -0,0 +1,43 @@
+---
+source: index-scheduler/src/lib.rs
+---
+### Autobatching Enabled = true
+### Processing Tasks:
+[]
+----------------------------------------------------------------------
+### All Tasks:
+0 {uid: 0, status: failed, error: ResponseError { code: 200, message: "Index `doggos` not found.", error_code: "index_not_found", error_type: "invalid_request", error_link: "https://docs.meilisearch.com/errors#index_not_found" }, details: { received_document_ids: 2, deleted_documents: Some(0) }, kind: DocumentDeletion { index_uid: "doggos", documents_ids: ["1", "2"] }}
+1 {uid: 1, status: enqueued, details: { received_documents: 3, indexed_documents: None }, kind: DocumentAdditionOrUpdate { index_uid: "doggos", primary_key: Some("id"), method: ReplaceDocuments, content_file: 00000000-0000-0000-0000-000000000000, documents_count: 3, allow_index_creation: true }}
+----------------------------------------------------------------------
+### Status:
+enqueued [1,]
+failed [0,]
+----------------------------------------------------------------------
+### Kind:
+"documentAdditionOrUpdate" [1,]
+"documentDeletion" [0,]
+----------------------------------------------------------------------
+### Index Tasks:
+doggos [0,1,]
+----------------------------------------------------------------------
+### Index Mapper:
+
+----------------------------------------------------------------------
+### Canceled By:
+
+----------------------------------------------------------------------
+### Enqueued At:
+[timestamp] [0,]
+[timestamp] [1,]
+----------------------------------------------------------------------
+### Started At:
+[timestamp] [0,]
+----------------------------------------------------------------------
+### Finished At:
+[timestamp] [0,]
+----------------------------------------------------------------------
+### File Store:
+00000000-0000-0000-0000-000000000000
+
+----------------------------------------------------------------------
+

index-scheduler/src/snapshots/lib.rs/document_deletion_and_document_addition/after_last_successful_addition.snap

@@ -0,0 +1,46 @@
+---
+source: index-scheduler/src/lib.rs
+---
+### Autobatching Enabled = true
+### Processing Tasks:
+[]
+----------------------------------------------------------------------
+### All Tasks:
+0 {uid: 0, status: failed, error: ResponseError { code: 200, message: "Index `doggos` not found.", error_code: "index_not_found", error_type: "invalid_request", error_link: "https://docs.meilisearch.com/errors#index_not_found" }, details: { received_document_ids: 2, deleted_documents: Some(0) }, kind: DocumentDeletion { index_uid: "doggos", documents_ids: ["1", "2"] }}
+1 {uid: 1, status: succeeded, details: { received_documents: 3, indexed_documents: Some(3) }, kind: DocumentAdditionOrUpdate { index_uid: "doggos", primary_key: Some("id"), method: ReplaceDocuments, content_file: 00000000-0000-0000-0000-000000000000, documents_count: 3, allow_index_creation: true }}
+----------------------------------------------------------------------
+### Status:
+enqueued []
+succeeded [1,]
+failed [0,]
+----------------------------------------------------------------------
+### Kind:
+"documentAdditionOrUpdate" [1,]
+"documentDeletion" [0,]
+----------------------------------------------------------------------
+### Index Tasks:
+doggos [0,1,]
+----------------------------------------------------------------------
+### Index Mapper:
+doggos: { number_of_documents: 3, field_distribution: {"catto": 1, "doggo": 2, "id": 3} }
+
+----------------------------------------------------------------------
+### Canceled By:
+
+----------------------------------------------------------------------
+### Enqueued At:
+[timestamp] [0,]
+[timestamp] [1,]
+----------------------------------------------------------------------
+### Started At:
+[timestamp] [0,]
+[timestamp] [1,]
+----------------------------------------------------------------------
+### Finished At:
+[timestamp] [0,]
+[timestamp] [1,]
+----------------------------------------------------------------------
+### File Store:
+
+----------------------------------------------------------------------
+

index-scheduler/src/snapshots/lib.rs/document_deletion_and_document_addition/documents.snap

@@ -0,0 +1,17 @@
+---
+source: index-scheduler/src/lib.rs
+---
+[
+  {
+    "id": 1,
+    "doggo": "jean bob"
+  },
+  {
+    "id": 2,
+    "catto": "jorts"
+  },
+  {
+    "id": 3,
+    "doggo": "bork"
+  }
+]

index-scheduler/src/snapshots/lib.rs/document_deletion_and_document_addition/registered_the_first_task.snap

@@ -0,0 +1,36 @@
+---
+source: index-scheduler/src/lib.rs
+---
+### Autobatching Enabled = true
+### Processing Tasks:
+[]
+----------------------------------------------------------------------
+### All Tasks:
+0 {uid: 0, status: enqueued, details: { received_document_ids: 2, deleted_documents: None }, kind: DocumentDeletion { index_uid: "doggos", documents_ids: ["1", "2"] }}
+----------------------------------------------------------------------
+### Status:
+enqueued [0,]
+----------------------------------------------------------------------
+### Kind:
+"documentDeletion" [0,]
+----------------------------------------------------------------------
+### Index Tasks:
+doggos [0,]
+----------------------------------------------------------------------
+### Index Mapper:
+
+----------------------------------------------------------------------
+### Canceled By:
+
+----------------------------------------------------------------------
+### Enqueued At:
+[timestamp] [0,]
+----------------------------------------------------------------------
+### Started At:
+----------------------------------------------------------------------
+### Finished At:
+----------------------------------------------------------------------
+### File Store:
+
+----------------------------------------------------------------------
+

index-scheduler/src/snapshots/lib.rs/document_deletion_and_document_addition/registered_the_second_task.snap

@@ -0,0 +1,40 @@
+---
+source: index-scheduler/src/lib.rs
+---
+### Autobatching Enabled = true
+### Processing Tasks:
+[]
+----------------------------------------------------------------------
+### All Tasks:
+0 {uid: 0, status: enqueued, details: { received_document_ids: 2, deleted_documents: None }, kind: DocumentDeletion { index_uid: "doggos", documents_ids: ["1", "2"] }}
+1 {uid: 1, status: enqueued, details: { received_documents: 3, indexed_documents: None }, kind: DocumentAdditionOrUpdate { index_uid: "doggos", primary_key: Some("id"), method: ReplaceDocuments, content_file: 00000000-0000-0000-0000-000000000000, documents_count: 3, allow_index_creation: true }}
+----------------------------------------------------------------------
+### Status:
+enqueued [0,1,]
+----------------------------------------------------------------------
+### Kind:
+"documentAdditionOrUpdate" [1,]
+"documentDeletion" [0,]
+----------------------------------------------------------------------
+### Index Tasks:
+doggos [0,1,]
+----------------------------------------------------------------------
+### Index Mapper:
+
+----------------------------------------------------------------------
+### Canceled By:
+
+----------------------------------------------------------------------
+### Enqueued At:
+[timestamp] [0,]
+[timestamp] [1,]
+----------------------------------------------------------------------
+### Started At:
+----------------------------------------------------------------------
+### Finished At:
+----------------------------------------------------------------------
+### File Store:
+00000000-0000-0000-0000-000000000000
+
+----------------------------------------------------------------------
+

index-scheduler/src/utils.rs

@@ -466,7 +466,7 @@ impl IndexScheduler {
                         }
                     }
                     Details::DocumentDeletionByFilter { deleted_documents, original_filter: _ } => {
-                        assert_eq!(kind.as_kind(), Kind::DocumentDeletionByFilter);
+                        assert_eq!(kind.as_kind(), Kind::DocumentDeletion);
                         let (index_uid, _) = if let KindWithContent::DocumentDeletionByFilter {
                             ref index_uid,
                             ref filter_expr,

meilisearch-auth/src/lib.rs

@@ -45,6 +45,11 @@ impl AuthController {
         self.store.size()
     }
 
+    /// Return the used size of the `AuthController` database in bytes.
+    pub fn used_size(&self) -> Result<u64> {
+        self.store.used_size()
+    }
+
     pub fn create_key(&self, create_key: CreateApiKey) -> Result<Key> {
         match self.store.get_api_key(create_key.uid)? {
             Some(_) => Err(AuthControllerError::ApiKeyAlreadyExists(create_key.uid.to_string())),

meilisearch-auth/src/store.rs

@@ -55,9 +55,11 @@ impl HeedAuthStore {
         let path = path.as_ref().join(AUTH_DB_PATH);
         create_dir_all(&path)?;
         let env = Arc::new(open_auth_store_env(path.as_ref())?);
-        let keys = env.create_database(Some(KEY_DB_NAME))?;
+        let mut wtxn = env.write_txn()?;
+        let keys = env.create_database(&mut wtxn, Some(KEY_DB_NAME))?;
         let action_keyid_index_expiration =
-            env.create_database(Some(KEY_ID_ACTION_INDEX_EXPIRATION_DB_NAME))?;
+            env.create_database(&mut wtxn, Some(KEY_ID_ACTION_INDEX_EXPIRATION_DB_NAME))?;
+        wtxn.commit()?;
         Ok(Self { env, keys, action_keyid_index_expiration, should_close_on_drop: true })
     }
 
@@ -73,6 +75,11 @@ impl HeedAuthStore {
         Ok(self.env.real_disk_size()?)
     }
 
+    /// Return the number of bytes actually used in the database
+    pub fn used_size(&self) -> Result<u64> {
+        Ok(self.env.non_free_pages_size()?)
+    }
+
     pub fn set_drop_on_close(&mut self, v: bool) {
         self.should_close_on_drop = v;
     }

meilisearch-types/src/deserr/mod.rs

@@ -150,6 +150,7 @@ make_missing_field_convenience_builder!(MissingApiKeyActions, missing_api_key_ac
 make_missing_field_convenience_builder!(MissingApiKeyExpiresAt, missing_api_key_expires_at);
 make_missing_field_convenience_builder!(MissingApiKeyIndexes, missing_api_key_indexes);
 make_missing_field_convenience_builder!(MissingSwapIndexes, missing_swap_indexes);
+make_missing_field_convenience_builder!(MissingDocumentFilter, missing_document_filter);
 
 // Integrate a sub-error into a [`DeserrError`] by taking its error message but using
 // the default error code (C) from `Self`

meilisearch-types/src/error.rs

@@ -214,12 +214,12 @@ InvalidApiKeyUid                      , InvalidRequest       , BAD_REQUEST ;
 InvalidContentType                    , InvalidRequest       , UNSUPPORTED_MEDIA_TYPE ;
 InvalidDocumentCsvDelimiter           , InvalidRequest       , BAD_REQUEST ;
 InvalidDocumentFields                 , InvalidRequest       , BAD_REQUEST ;
+MissingDocumentFilter                 , InvalidRequest       , BAD_REQUEST ;
 InvalidDocumentFilter                 , InvalidRequest       , BAD_REQUEST ;
 InvalidDocumentGeoField               , InvalidRequest       , BAD_REQUEST ;
 InvalidDocumentId                     , InvalidRequest       , BAD_REQUEST ;
 InvalidDocumentLimit                  , InvalidRequest       , BAD_REQUEST ;
 InvalidDocumentOffset                 , InvalidRequest       , BAD_REQUEST ;
-InvalidDocumentDeleteFilter           , InvalidRequest       , BAD_REQUEST ;
 InvalidIndexLimit                     , InvalidRequest       , BAD_REQUEST ;
 InvalidIndexOffset                    , InvalidRequest       , BAD_REQUEST ;
 InvalidIndexPrimaryKey                , InvalidRequest       , BAD_REQUEST ;

meilisearch-types/src/tasks.rs

@@ -395,7 +395,6 @@ impl std::error::Error for ParseTaskStatusError {}
 pub enum Kind {
     DocumentAdditionOrUpdate,
     DocumentDeletion,
-    DocumentDeletionByFilter,
     SettingsUpdate,
     IndexCreation,
     IndexDeletion,
@@ -412,7 +411,6 @@ impl Kind {
         match self {
             Kind::DocumentAdditionOrUpdate
             | Kind::DocumentDeletion
-            | Kind::DocumentDeletionByFilter
             | Kind::SettingsUpdate
             | Kind::IndexCreation
             | Kind::IndexDeletion
@@ -430,7 +428,6 @@ impl Display for Kind {
         match self {
             Kind::DocumentAdditionOrUpdate => write!(f, "documentAdditionOrUpdate"),
             Kind::DocumentDeletion => write!(f, "documentDeletion"),
-            Kind::DocumentDeletionByFilter => write!(f, "documentDeletionByFilter"),
             Kind::SettingsUpdate => write!(f, "settingsUpdate"),
             Kind::IndexCreation => write!(f, "indexCreation"),
             Kind::IndexDeletion => write!(f, "indexDeletion"),

meilisearch/src/analytics/mock_analytics.rs

@@ -5,7 +5,7 @@ use actix_web::HttpRequest;
 use meilisearch_types::InstanceUid;
 use serde_json::Value;
 
-use super::{find_user_id, Analytics, DocumentDeletionKind};
+use super::{find_user_id, Analytics, DocumentDeletionKind, DocumentFetchKind};
 use crate::routes::indexes::documents::UpdateDocumentsQuery;
 use crate::routes::tasks::TasksFilterQuery;
 use crate::Opt;
@@ -71,6 +71,8 @@ impl Analytics for MockAnalytics {
         _request: &HttpRequest,
     ) {
     }
+    fn get_fetch_documents(&self, _documents_query: &DocumentFetchKind, _request: &HttpRequest) {}
+    fn post_fetch_documents(&self, _documents_query: &DocumentFetchKind, _request: &HttpRequest) {}
     fn get_tasks(&self, _query: &TasksFilterQuery, _request: &HttpRequest) {}
     fn health_seen(&self, _request: &HttpRequest) {}
 }

meilisearch/src/analytics/mod.rs

@@ -67,6 +67,12 @@ pub enum DocumentDeletionKind {
     PerFilter,
 }
 
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub enum DocumentFetchKind {
+    PerDocumentId,
+    Normal { with_filter: bool, limit: usize, offset: usize },
+}
+
 pub trait Analytics: Sync + Send {
     fn instance_uid(&self) -> Option<&InstanceUid>;
 
@@ -90,6 +96,12 @@ pub trait Analytics: Sync + Send {
         request: &HttpRequest,
     );
 
+    // this method should be called to aggregate a fetch documents request
+    fn get_fetch_documents(&self, documents_query: &DocumentFetchKind, request: &HttpRequest);
+
+    // this method should be called to aggregate a fetch documents request
+    fn post_fetch_documents(&self, documents_query: &DocumentFetchKind, request: &HttpRequest);
+
     // this method should be called to aggregate a add documents request
     fn delete_documents(&self, kind: DocumentDeletionKind, request: &HttpRequest);
 

meilisearch/src/analytics/segment_analytics.rs

@@ -23,7 +23,9 @@ use tokio::select;
 use tokio::sync::mpsc::{self, Receiver, Sender};
 use uuid::Uuid;
 
-use super::{config_user_id_path, DocumentDeletionKind, MEILISEARCH_CONFIG_PATH};
+use super::{
+    config_user_id_path, DocumentDeletionKind, DocumentFetchKind, MEILISEARCH_CONFIG_PATH,
+};
 use crate::analytics::Analytics;
 use crate::option::{default_http_addr, IndexerOpts, MaxMemory, MaxThreads, ScheduleSnapshot};
 use crate::routes::indexes::documents::UpdateDocumentsQuery;
@@ -72,6 +74,8 @@ pub enum AnalyticsMsg {
     AggregateAddDocuments(DocumentsAggregator),
     AggregateDeleteDocuments(DocumentsDeletionAggregator),
     AggregateUpdateDocuments(DocumentsAggregator),
+    AggregateGetFetchDocuments(DocumentsFetchAggregator),
+    AggregatePostFetchDocuments(DocumentsFetchAggregator),
     AggregateTasks(TasksAggregator),
     AggregateHealth(HealthAggregator),
 }
@@ -139,6 +143,8 @@ impl SegmentAnalytics {
             add_documents_aggregator: DocumentsAggregator::default(),
             delete_documents_aggregator: DocumentsDeletionAggregator::default(),
             update_documents_aggregator: DocumentsAggregator::default(),
+            get_fetch_documents_aggregator: DocumentsFetchAggregator::default(),
+            post_fetch_documents_aggregator: DocumentsFetchAggregator::default(),
             get_tasks_aggregator: TasksAggregator::default(),
             health_aggregator: HealthAggregator::default(),
         });
@@ -205,6 +211,16 @@ impl super::Analytics for SegmentAnalytics {
         let _ = self.sender.try_send(AnalyticsMsg::AggregateUpdateDocuments(aggregate));
     }
 
+    fn get_fetch_documents(&self, documents_query: &DocumentFetchKind, request: &HttpRequest) {
+        let aggregate = DocumentsFetchAggregator::from_query(documents_query, request);
+        let _ = self.sender.try_send(AnalyticsMsg::AggregateGetFetchDocuments(aggregate));
+    }
+
+    fn post_fetch_documents(&self, documents_query: &DocumentFetchKind, request: &HttpRequest) {
+        let aggregate = DocumentsFetchAggregator::from_query(documents_query, request);
+        let _ = self.sender.try_send(AnalyticsMsg::AggregatePostFetchDocuments(aggregate));
+    }
+
     fn get_tasks(&self, query: &TasksFilterQuery, request: &HttpRequest) {
         let aggregate = TasksAggregator::from_query(query, request);
         let _ = self.sender.try_send(AnalyticsMsg::AggregateTasks(aggregate));
@@ -225,6 +241,7 @@ impl super::Analytics for SegmentAnalytics {
 struct Infos {
     env: String,
     experimental_enable_metrics: bool,
+    experimental_reduce_indexing_memory_usage: bool,
     db_path: bool,
     import_dump: bool,
     dump_dir: bool,
@@ -258,6 +275,7 @@ impl From<Opt> for Infos {
         let Opt {
             db_path,
             experimental_enable_metrics,
+            experimental_reduce_indexing_memory_usage,
             http_addr,
             master_key: _,
             env,
@@ -300,6 +318,7 @@ impl From<Opt> for Infos {
         Self {
             env,
             experimental_enable_metrics,
+            experimental_reduce_indexing_memory_usage,
             db_path: db_path != PathBuf::from("./data.ms"),
             import_dump: import_dump.is_some(),
             dump_dir: dump_dir != PathBuf::from("dumps/"),
@@ -338,6 +357,8 @@ pub struct Segment {
     add_documents_aggregator: DocumentsAggregator,
     delete_documents_aggregator: DocumentsDeletionAggregator,
     update_documents_aggregator: DocumentsAggregator,
+    get_fetch_documents_aggregator: DocumentsFetchAggregator,
+    post_fetch_documents_aggregator: DocumentsFetchAggregator,
     get_tasks_aggregator: TasksAggregator,
     health_aggregator: HealthAggregator,
 }
@@ -400,6 +421,8 @@ impl Segment {
                         Some(AnalyticsMsg::AggregateAddDocuments(agreg)) => self.add_documents_aggregator.aggregate(agreg),
                         Some(AnalyticsMsg::AggregateDeleteDocuments(agreg)) => self.delete_documents_aggregator.aggregate(agreg),
                         Some(AnalyticsMsg::AggregateUpdateDocuments(agreg)) => self.update_documents_aggregator.aggregate(agreg),
+                        Some(AnalyticsMsg::AggregateGetFetchDocuments(agreg)) => self.get_fetch_documents_aggregator.aggregate(agreg),
+                        Some(AnalyticsMsg::AggregatePostFetchDocuments(agreg)) => self.post_fetch_documents_aggregator.aggregate(agreg),
                         Some(AnalyticsMsg::AggregateTasks(agreg)) => self.get_tasks_aggregator.aggregate(agreg),
                         Some(AnalyticsMsg::AggregateHealth(agreg)) => self.health_aggregator.aggregate(agreg),
                         None => (),
@@ -450,6 +473,10 @@ impl Segment {
             .into_event(&self.user, "Documents Deleted");
         let update_documents = std::mem::take(&mut self.update_documents_aggregator)
             .into_event(&self.user, "Documents Updated");
+        let get_fetch_documents = std::mem::take(&mut self.get_fetch_documents_aggregator)
+            .into_event(&self.user, "Documents Fetched GET");
+        let post_fetch_documents = std::mem::take(&mut self.post_fetch_documents_aggregator)
+            .into_event(&self.user, "Documents Fetched POST");
         let get_tasks =
             std::mem::take(&mut self.get_tasks_aggregator).into_event(&self.user, "Tasks Seen");
         let health =
@@ -473,6 +500,12 @@ impl Segment {
         if let Some(update_documents) = update_documents {
             let _ = self.batcher.push(update_documents).await;
         }
+        if let Some(get_fetch_documents) = get_fetch_documents {
+            let _ = self.batcher.push(get_fetch_documents).await;
+        }
+        if let Some(post_fetch_documents) = post_fetch_documents {
+            let _ = self.batcher.push(post_fetch_documents).await;
+        }
         if let Some(get_tasks) = get_tasks {
             let _ = self.batcher.push(get_tasks).await;
         }
@@ -1135,3 +1168,76 @@ impl HealthAggregator {
         })
     }
 }
+
+#[derive(Default, Serialize)]
+pub struct DocumentsFetchAggregator {
+    #[serde(skip)]
+    timestamp: Option<OffsetDateTime>,
+
+    // context
+    #[serde(rename = "user-agent")]
+    user_agents: HashSet<String>,
+
+    #[serde(rename = "requests.max_limit")]
+    total_received: usize,
+
+    // a call on ../documents/:doc_id
+    per_document_id: bool,
+    // if a filter was used
+    per_filter: bool,
+
+    // pagination
+    #[serde(rename = "pagination.max_limit")]
+    max_limit: usize,
+    #[serde(rename = "pagination.max_offset")]
+    max_offset: usize,
+}
+
+impl DocumentsFetchAggregator {
+    pub fn from_query(query: &DocumentFetchKind, request: &HttpRequest) -> Self {
+        let (limit, offset) = match query {
+            DocumentFetchKind::PerDocumentId => (1, 0),
+            DocumentFetchKind::Normal { limit, offset, .. } => (*limit, *offset),
+        };
+        Self {
+            timestamp: Some(OffsetDateTime::now_utc()),
+            user_agents: extract_user_agents(request).into_iter().collect(),
+            total_received: 1,
+            per_document_id: matches!(query, DocumentFetchKind::PerDocumentId),
+            per_filter: matches!(query, DocumentFetchKind::Normal { with_filter, .. } if *with_filter),
+            max_limit: limit,
+            max_offset: offset,
+        }
+    }
+
+    /// Aggregate one [DocumentsFetchAggregator] into another.
+    pub fn aggregate(&mut self, other: Self) {
+        if self.timestamp.is_none() {
+            self.timestamp = other.timestamp;
+        }
+        for user_agent in other.user_agents {
+            self.user_agents.insert(user_agent);
+        }
+
+        self.total_received = self.total_received.saturating_add(other.total_received);
+        self.per_document_id |= other.per_document_id;
+        self.per_filter |= other.per_filter;
+
+        self.max_limit = self.max_limit.max(other.max_limit);
+        self.max_offset = self.max_offset.max(other.max_offset);
+    }
+
+    pub fn into_event(self, user: &User, event_name: &str) -> Option<Track> {
+        // if we had no timestamp it means we never encountered any events and
+        // thus we don't need to send this event.
+        let timestamp = self.timestamp?;
+
+        Some(Track {
+            timestamp: Some(timestamp),
+            user: user.clone(),
+            event: event_name.to_string(),
+            properties: serde_json::to_value(self).ok()?,
+            ..Default::default()
+        })
+    }
+}

meilisearch/src/error.rs

@@ -61,7 +61,7 @@ impl ErrorCode for MeilisearchHttpError {
             MeilisearchHttpError::MissingPayload(_) => Code::MissingPayload,
             MeilisearchHttpError::InvalidContentType(_, _) => Code::InvalidContentType,
             MeilisearchHttpError::DocumentNotFound(_) => Code::DocumentNotFound,
-            MeilisearchHttpError::EmptyFilter => Code::InvalidDocumentDeleteFilter,
+            MeilisearchHttpError::EmptyFilter => Code::InvalidDocumentFilter,
             MeilisearchHttpError::InvalidExpression(_, _) => Code::InvalidSearchFilter,
             MeilisearchHttpError::PayloadTooLarge(_) => Code::PayloadTooLarge,
             MeilisearchHttpError::SwapIndexPayloadWrongLength(_) => Code::InvalidSwapIndexes,

meilisearch/src/lib.rs

@@ -232,6 +232,7 @@ fn open_or_create_database_unchecked(
             dumps_path: opt.dump_dir.clone(),
             task_db_size: opt.max_task_db_size.get_bytes() as usize,
             index_base_map_size: opt.max_index_size.get_bytes() as usize,
+            enable_mdb_writemap: opt.experimental_reduce_indexing_memory_usage,
             indexer_config: (&opt.indexer_options).try_into()?,
             autobatching_enabled: true,
             max_number_of_tasks: 1_000_000,

meilisearch/src/main.rs

@@ -29,6 +29,11 @@ fn setup(opt: &Opt) -> anyhow::Result<()> {
 async fn main() -> anyhow::Result<()> {
     let (opt, config_read_from) = Opt::try_build()?;
 
+    anyhow::ensure!(
+        !(cfg!(windows) && opt.experimental_reduce_indexing_memory_usage),
+        "The `experimental-reduce-indexing-memory-usage` flag is not supported on Windows"
+    );
+
     setup(&opt)?;
 
     match (opt.env.as_ref(), &opt.master_key) {

meilisearch/src/metrics.rs

@@ -4,19 +4,31 @@ use prometheus::{
     register_int_gauge_vec, HistogramVec, IntCounterVec, IntGauge, IntGaugeVec,
 };
 
-const HTTP_RESPONSE_TIME_CUSTOM_BUCKETS: &[f64; 14] = &[
+/// Create evenly distributed buckets
-    0.0005, 0.0008, 0.00085, 0.0009, 0.00095, 0.001, 0.00105, 0.0011, 0.00115, 0.0012, 0.0015,
+fn create_buckets() -> [f64; 29] {
-    0.002, 0.003, 1.0,
+    (0..10)
-];
+        .chain((10..100).step_by(10))
+        .chain((100..=1000).step_by(100))
+        .map(|i| i as f64 / 1000.)
+        .collect::<Vec<_>>()
+        .try_into()
+        .unwrap()
+}
 
 lazy_static! {
-    pub static ref HTTP_REQUESTS_TOTAL: IntCounterVec = register_int_counter_vec!(
+    pub static ref HTTP_RESPONSE_TIME_CUSTOM_BUCKETS: [f64; 29] = create_buckets();
-        opts!("http_requests_total", "HTTP requests total"),
+    pub static ref MEILISEARCH_HTTP_REQUESTS_TOTAL: IntCounterVec = register_int_counter_vec!(
+        opts!("meilisearch_http_requests_total", "Meilisearch HTTP requests total"),
         &["method", "path"]
     )
     .expect("Can't create a metric");
     pub static ref MEILISEARCH_DB_SIZE_BYTES: IntGauge =
-        register_int_gauge!(opts!("meilisearch_db_size_bytes", "Meilisearch Db Size In Bytes"))
+        register_int_gauge!(opts!("meilisearch_db_size_bytes", "Meilisearch DB Size In Bytes"))
+            .expect("Can't create a metric");
+    pub static ref MEILISEARCH_USED_DB_SIZE_BYTES: IntGauge = register_int_gauge!(opts!(
+        "meilisearch_used_db_size_bytes",
+        "Meilisearch Used DB Size In Bytes"
+    ))
     .expect("Can't create a metric");
     pub static ref MEILISEARCH_INDEX_COUNT: IntGauge =
         register_int_gauge!(opts!("meilisearch_index_count", "Meilisearch Index Count"))
@@ -26,11 +38,16 @@ lazy_static! {
         &["index"]
     )
     .expect("Can't create a metric");
-    pub static ref HTTP_RESPONSE_TIME_SECONDS: HistogramVec = register_histogram_vec!(
+    pub static ref MEILISEARCH_HTTP_RESPONSE_TIME_SECONDS: HistogramVec = register_histogram_vec!(
         "http_response_time_seconds",
         "HTTP response times",
         &["method", "path"],
         HTTP_RESPONSE_TIME_CUSTOM_BUCKETS.to_vec()
     )
     .expect("Can't create a metric");
+    pub static ref MEILISEARCH_NB_TASKS: IntGaugeVec = register_int_gauge_vec!(
+        opts!("meilisearch_nb_tasks", "Meilisearch Number of tasks"),
+        &["kind", "value"]
+    )
+    .expect("Can't create a metric");
 }

meilisearch/src/middleware.rs

@@ -52,11 +52,11 @@ where
         if is_registered_resource {
             let request_method = req.method().to_string();
             histogram_timer = Some(
-                crate::metrics::HTTP_RESPONSE_TIME_SECONDS
+                crate::metrics::MEILISEARCH_HTTP_RESPONSE_TIME_SECONDS
                     .with_label_values(&[&request_method, request_path])
                     .start_timer(),
             );
-            crate::metrics::HTTP_REQUESTS_TOTAL
+            crate::metrics::MEILISEARCH_HTTP_REQUESTS_TOTAL
                 .with_label_values(&[&request_method, request_path])
                 .inc();
         }

meilisearch/src/option.rs

@@ -48,6 +48,8 @@ const MEILI_IGNORE_DUMP_IF_DB_EXISTS: &str = "MEILI_IGNORE_DUMP_IF_DB_EXISTS";
 const MEILI_DUMP_DIR: &str = "MEILI_DUMP_DIR";
 const MEILI_LOG_LEVEL: &str = "MEILI_LOG_LEVEL";
 const MEILI_EXPERIMENTAL_ENABLE_METRICS: &str = "MEILI_EXPERIMENTAL_ENABLE_METRICS";
+const MEILI_EXPERIMENTAL_REDUCE_INDEXING_MEMORY_USAGE: &str =
+    "MEILI_EXPERIMENTAL_REDUCE_INDEXING_MEMORY_USAGE";
 
 const DEFAULT_CONFIG_FILE_PATH: &str = "./config.toml";
 const DEFAULT_DB_PATH: &str = "./data.ms";
@@ -293,6 +295,11 @@ pub struct Opt {
     #[serde(default)]
     pub experimental_enable_metrics: bool,
 
+    /// Experimental RAM reduction during indexing, do not use in production, see: <https://github.com/meilisearch/product/discussions/652>
+    #[clap(long, env = MEILI_EXPERIMENTAL_REDUCE_INDEXING_MEMORY_USAGE)]
+    #[serde(default)]
+    pub experimental_reduce_indexing_memory_usage: bool,
+
     #[serde(flatten)]
     #[clap(flatten)]
     pub indexer_options: IndexerOpts,
@@ -385,6 +392,7 @@ impl Opt {
             #[cfg(all(not(debug_assertions), feature = "analytics"))]
             no_analytics,
             experimental_enable_metrics: enable_metrics_route,
+            experimental_reduce_indexing_memory_usage: reduce_indexing_memory_usage,
         } = self;
         export_to_env_if_not_present(MEILI_DB_PATH, db_path);
         export_to_env_if_not_present(MEILI_HTTP_ADDR, http_addr);
@@ -426,6 +434,10 @@ impl Opt {
             MEILI_EXPERIMENTAL_ENABLE_METRICS,
             enable_metrics_route.to_string(),
         );
+        export_to_env_if_not_present(
+            MEILI_EXPERIMENTAL_REDUCE_INDEXING_MEMORY_USAGE,
+            reduce_indexing_memory_usage.to_string(),
+        );
         indexer_options.export_to_env();
     }
 

meilisearch/src/routes/indexes/documents.rs

@@ -29,7 +29,7 @@ use tempfile::tempfile;
 use tokio::fs::File;
 use tokio::io::{AsyncSeekExt, AsyncWriteExt, BufWriter};
 
-use crate::analytics::{Analytics, DocumentDeletionKind};
+use crate::analytics::{Analytics, DocumentDeletionKind, DocumentFetchKind};
 use crate::error::MeilisearchHttpError;
 use crate::error::PayloadError::ReceivePayload;
 use crate::extractors::authentication::policies::*;
@@ -97,10 +97,14 @@ pub async fn get_document(
     index_scheduler: GuardedData<ActionPolicy<{ actions::DOCUMENTS_GET }>, Data<IndexScheduler>>,
     document_param: web::Path<DocumentParam>,
     params: AwebQueryParameter<GetDocument, DeserrQueryParamError>,
+    req: HttpRequest,
+    analytics: web::Data<dyn Analytics>,
 ) -> Result<HttpResponse, ResponseError> {
     let DocumentParam { index_uid, document_id } = document_param.into_inner();
     let index_uid = IndexUid::try_from(index_uid)?;
 
+    analytics.get_fetch_documents(&DocumentFetchKind::PerDocumentId, &req);
+
     let GetDocument { fields } = params.into_inner();
     let attributes_to_retrieve = fields.merge_star_and_none();
 
@@ -161,16 +165,31 @@ pub async fn documents_by_query_post(
     index_scheduler: GuardedData<ActionPolicy<{ actions::DOCUMENTS_GET }>, Data<IndexScheduler>>,
     index_uid: web::Path<String>,
     body: AwebJson<BrowseQuery, DeserrJsonError>,
+    req: HttpRequest,
+    analytics: web::Data<dyn Analytics>,
 ) -> Result<HttpResponse, ResponseError> {
     debug!("called with body: {:?}", body);
 
-    documents_by_query(&index_scheduler, index_uid, body.into_inner())
+    let body = body.into_inner();
+
+    analytics.post_fetch_documents(
+        &DocumentFetchKind::Normal {
+            with_filter: body.filter.is_some(),
+            limit: body.limit,
+            offset: body.offset,
+        },
+        &req,
+    );
+
+    documents_by_query(&index_scheduler, index_uid, body)
 }
 
 pub async fn get_documents(
     index_scheduler: GuardedData<ActionPolicy<{ actions::DOCUMENTS_GET }>, Data<IndexScheduler>>,
     index_uid: web::Path<String>,
     params: AwebQueryParameter<BrowseQueryGet, DeserrQueryParamError>,
+    req: HttpRequest,
+    analytics: web::Data<dyn Analytics>,
 ) -> Result<HttpResponse, ResponseError> {
     debug!("called with params: {:?}", params);
 
@@ -191,6 +210,15 @@ pub async fn get_documents(
         filter,
     };
 
+    analytics.get_fetch_documents(
+        &DocumentFetchKind::Normal {
+            with_filter: query.filter.is_some(),
+            limit: query.limit,
+            offset: query.offset,
+        },
+        &req,
+    );
+
     documents_by_query(&index_scheduler, index_uid, query)
 }
 
@@ -458,7 +486,7 @@ pub async fn delete_documents_batch(
 #[derive(Debug, Deserr)]
 #[deserr(error = DeserrJsonError, rename_all = camelCase, deny_unknown_fields)]
 pub struct DocumentDeletionByFilter {
-    #[deserr(error = DeserrJsonError<InvalidDocumentDeleteFilter>)]
+    #[deserr(error = DeserrJsonError<InvalidDocumentFilter>, missing_field_error = DeserrJsonError::missing_document_filter)]
     filter: Value,
 }
 
@@ -480,8 +508,8 @@ pub async fn delete_documents_by_filter(
     || -> Result<_, ResponseError> {
         Ok(crate::search::parse_filter(&filter)?.ok_or(MeilisearchHttpError::EmptyFilter)?)
     }()
-    // and whatever was the error, the error code should always be an InvalidDocumentDeleteFilter
+    // and whatever was the error, the error code should always be an InvalidDocumentFilter
-    .map_err(|err| ResponseError::from_msg(err.message, Code::InvalidDocumentDeleteFilter))?;
+    .map_err(|err| ResponseError::from_msg(err.message, Code::InvalidDocumentFilter))?;
     let task = KindWithContent::DocumentDeletionByFilter { index_uid, filter_expr: filter };
 
     let task: SummarizedTaskView =
@@ -540,7 +568,12 @@ fn retrieve_documents<S: AsRef<str>>(
     };
 
     let candidates = if let Some(filter) = filter {
-        filter.evaluate(&rtxn, index)?
+        filter.evaluate(&rtxn, index).map_err(|err| match err {
+            milli::Error::UserError(milli::UserError::InvalidFilter(_)) => {
+                ResponseError::from_msg(err.to_string(), Code::InvalidDocumentFilter)
+            }
+            e => e.into(),
+        })?
     } else {
         index.documents_ids(&rtxn)?
     };

meilisearch/src/routes/metrics.rs

@@ -17,7 +17,7 @@ pub fn configure(config: &mut web::ServiceConfig) {
 
 pub async fn get_metrics(
     index_scheduler: GuardedData<ActionPolicy<{ actions::METRICS_GET }>, Data<IndexScheduler>>,
-    auth_controller: GuardedData<ActionPolicy<{ actions::METRICS_GET }>, Data<AuthController>>,
+    auth_controller: Data<AuthController>,
 ) -> Result<HttpResponse, ResponseError> {
     let auth_filters = index_scheduler.filters();
     if !auth_filters.all_indexes_authorized() {
@@ -28,10 +28,10 @@ pub async fn get_metrics(
         return Err(error);
     }
 
-    let response =
+    let response = create_all_stats((*index_scheduler).clone(), auth_controller, auth_filters)?;
-        create_all_stats((*index_scheduler).clone(), (*auth_controller).clone(), auth_filters)?;
 
     crate::metrics::MEILISEARCH_DB_SIZE_BYTES.set(response.database_size as i64);
+    crate::metrics::MEILISEARCH_USED_DB_SIZE_BYTES.set(response.used_database_size as i64);
     crate::metrics::MEILISEARCH_INDEX_COUNT.set(response.indexes.len() as i64);
 
     for (index, value) in response.indexes.iter() {
@@ -40,6 +40,14 @@ pub async fn get_metrics(
             .set(value.number_of_documents as i64);
     }
 
+    for (kind, value) in index_scheduler.get_stats()? {
+        for (value, count) in value {
+            crate::metrics::MEILISEARCH_NB_TASKS
+                .with_label_values(&[&kind, &value])
+                .set(count as i64);
+        }
+    }
+
     let encoder = TextEncoder::new();
     let mut buffer = vec![];
     encoder.encode(&prometheus::gather(), &mut buffer).expect("Failed to encode metrics");

meilisearch/src/routes/mod.rs

@@ -231,6 +231,8 @@ pub async fn running() -> HttpResponse {
 #[serde(rename_all = "camelCase")]
 pub struct Stats {
     pub database_size: u64,
+    #[serde(skip)]
+    pub used_database_size: u64,
     #[serde(serialize_with = "time::serde::rfc3339::option::serialize")]
     pub last_update: Option<OffsetDateTime>,
     pub indexes: BTreeMap<String, indexes::IndexStats>,
@@ -259,6 +261,7 @@ pub fn create_all_stats(
     let mut last_task: Option<OffsetDateTime> = None;
     let mut indexes = BTreeMap::new();
     let mut database_size = 0;
+    let mut used_database_size = 0;
 
     for index_uid in index_scheduler.index_names()? {
         // Accumulate the size of all indexes, even unauthorized ones, so
@@ -266,6 +269,7 @@ pub fn create_all_stats(
         // See <https://github.com/meilisearch/meilisearch/pull/3541#discussion_r1126747643> for context.
         let stats = index_scheduler.index_stats(&index_uid)?;
         database_size += stats.inner_stats.database_size;
+        used_database_size += stats.inner_stats.used_database_size;
 
         if !filters.is_index_authorized(&index_uid) {
             continue;
@@ -278,10 +282,14 @@ pub fn create_all_stats(
     }
 
     database_size += index_scheduler.size()?;
+    used_database_size += index_scheduler.used_size()?;
     database_size += auth_controller.size()?;
-    database_size += index_scheduler.compute_update_file_size()?;
+    used_database_size += auth_controller.used_size()?;
+    let update_file_size = index_scheduler.compute_update_file_size()?;
+    database_size += update_file_size;
+    used_database_size += update_file_size;
 
-    let stats = Stats { database_size, last_update: last_task, indexes };
+    let stats = Stats { database_size, used_database_size, last_update: last_task, indexes };
     Ok(stats)
 }
 

meilisearch/src/routes/tasks.rs

@@ -99,7 +99,7 @@ pub struct DetailsView {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub deleted_tasks: Option<Option<u64>>,
     #[serde(skip_serializing_if = "Option::is_none")]
-    pub original_filter: Option<String>,
+    pub original_filter: Option<Option<String>>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub dump_uid: Option<Option<String>>,
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -131,12 +131,13 @@ impl From<Details> for DetailsView {
             } => DetailsView {
                 provided_ids: Some(received_document_ids),
                 deleted_documents: Some(deleted_documents),
+                original_filter: Some(None),
                 ..DetailsView::default()
             },
             Details::DocumentDeletionByFilter { original_filter, deleted_documents } => {
                 DetailsView {
                     provided_ids: Some(0),
-                    original_filter: Some(original_filter),
+                    original_filter: Some(Some(original_filter)),
                     deleted_documents: Some(deleted_documents),
                     ..DetailsView::default()
                 }
@@ -148,7 +149,7 @@ impl From<Details> for DetailsView {
                 DetailsView {
                     matched_tasks: Some(matched_tasks),
                     canceled_tasks: Some(canceled_tasks),
-                    original_filter: Some(original_filter),
+                    original_filter: Some(Some(original_filter)),
                     ..DetailsView::default()
                 }
             }
@@ -156,7 +157,7 @@ impl From<Details> for DetailsView {
                 DetailsView {
                     matched_tasks: Some(matched_tasks),
                     deleted_tasks: Some(deleted_tasks),
-                    original_filter: Some(original_filter),
+                    original_filter: Some(Some(original_filter)),
                     ..DetailsView::default()
                 }
             }
@@ -729,7 +730,7 @@ mod tests {
             let err = deserr_query_params::<TaskDeletionOrCancelationQuery>(params).unwrap_err();
             snapshot!(meili_snap::json_string!(err), @r###"
             {
-              "message": "Invalid value in parameter `types`: `createIndex` is not a valid task type. Available types are `documentAdditionOrUpdate`, `documentDeletion`, `documentDeletionByFilter`, `settingsUpdate`, `indexCreation`, `indexDeletion`, `indexUpdate`, `indexSwap`, `taskCancelation`, `taskDeletion`, `dumpCreation`, `snapshotCreation`.",
+              "message": "Invalid value in parameter `types`: `createIndex` is not a valid task type. Available types are `documentAdditionOrUpdate`, `documentDeletion`, `settingsUpdate`, `indexCreation`, `indexDeletion`, `indexUpdate`, `indexSwap`, `taskCancelation`, `taskDeletion`, `dumpCreation`, `snapshotCreation`.",
               "code": "invalid_task_types",
               "type": "invalid_request",
               "link": "https://docs.meilisearch.com/errors#invalid_task_types"

meilisearch/tests/auth/authorization.rs

@@ -16,8 +16,11 @@ pub static AUTHORIZATIONS: Lazy<HashMap<(&'static str, &'static str), HashSet<&'
             ("GET",     "/indexes/products/search") =>                         hashset!{"search", "*"},
             ("POST",    "/indexes/products/documents") =>                      hashset!{"documents.add", "documents.*", "*"},
             ("GET",     "/indexes/products/documents") =>                      hashset!{"documents.get", "documents.*", "*"},
+            ("POST",    "/indexes/products/documents/fetch") =>                hashset!{"documents.get", "documents.*", "*"},
             ("GET",     "/indexes/products/documents/0") =>                    hashset!{"documents.get", "documents.*", "*"},
             ("DELETE",  "/indexes/products/documents/0") =>                    hashset!{"documents.delete", "documents.*", "*"},
+            ("POST",    "/indexes/products/documents/delete-batch") =>         hashset!{"documents.delete", "documents.*", "*"},
+            ("POST",    "/indexes/products/documents/delete") =>               hashset!{"documents.delete", "documents.*", "*"},
             ("GET",     "/tasks") =>                                           hashset!{"tasks.get", "tasks.*", "*"},
             ("DELETE",  "/tasks") =>                                           hashset!{"tasks.delete", "tasks.*", "*"},
             ("GET",     "/tasks?indexUid=products") =>                         hashset!{"tasks.get", "tasks.*", "*"},

meilisearch/tests/documents/errors.rs

@@ -180,9 +180,9 @@ async fn get_all_documents_bad_filter() {
     snapshot!(json_string!(response), @r###"
     {
       "message": "Attribute `doggo` is not filterable. This index does not have configured filterable attributes.\n1:6 doggo=bernese",
-      "code": "invalid_search_filter",
+      "code": "invalid_document_filter",
       "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_search_filter"
+      "link": "https://docs.meilisearch.com/errors#invalid_document_filter"
     }
     "###);
 }
@@ -547,9 +547,9 @@ async fn delete_document_by_filter() {
     snapshot!(json_string!(response), @r###"
     {
       "message": "Invalid syntax for the filter parameter: `expected String, Array, found: true`.",
-      "code": "invalid_document_delete_filter",
+      "code": "invalid_document_filter",
       "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_document_delete_filter"
+      "link": "https://docs.meilisearch.com/errors#invalid_document_filter"
     }
     "###);
 
@@ -559,9 +559,9 @@ async fn delete_document_by_filter() {
     snapshot!(json_string!(response), @r###"
     {
       "message": "Was expecting an operation `=`, `!=`, `>=`, `>`, `<=`, `<`, `IN`, `NOT IN`, `TO`, `EXISTS`, `NOT EXISTS`, `IS NULL`, `IS NOT NULL`, `IS EMPTY`, `IS NOT EMPTY`, `_geoRadius`, or `_geoBoundingBox` at `hello`.\n1:6 hello",
-      "code": "invalid_document_delete_filter",
+      "code": "invalid_document_filter",
       "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_document_delete_filter"
+      "link": "https://docs.meilisearch.com/errors#invalid_document_filter"
     }
     "###);
 
@@ -571,9 +571,21 @@ async fn delete_document_by_filter() {
     snapshot!(json_string!(response), @r###"
     {
       "message": "Sending an empty filter is forbidden.",
-      "code": "invalid_document_delete_filter",
+      "code": "invalid_document_filter",
       "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_document_delete_filter"
+      "link": "https://docs.meilisearch.com/errors#invalid_document_filter"
+    }
+    "###);
+
+    // do not send any filter
+    let (response, code) = index.delete_document_by_filter(json!({})).await;
+    snapshot!(code, @"400 Bad Request");
+    snapshot!(json_string!(response), @r###"
+    {
+      "message": "Missing field `filter`",
+      "code": "missing_document_filter",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#missing_document_filter"
     }
     "###);
 
@@ -630,9 +642,9 @@ async fn delete_document_by_filter() {
       },
       "error": {
         "message": "Attribute `doggo` is not filterable. This index does not have configured filterable attributes.\n1:6 doggo = bernese",
-        "code": "invalid_search_filter",
+        "code": "invalid_document_filter",
         "type": "invalid_request",
-        "link": "https://docs.meilisearch.com/errors#invalid_search_filter"
+        "link": "https://docs.meilisearch.com/errors#invalid_document_filter"
       },
       "duration": "[duration]",
       "enqueuedAt": "[date]",
@@ -664,9 +676,9 @@ async fn delete_document_by_filter() {
       },
       "error": {
         "message": "Attribute `catto` is not filterable. Available filterable attributes are: `doggo`.\n1:6 catto = jorts",
-        "code": "invalid_search_filter",
+        "code": "invalid_document_filter",
         "type": "invalid_request",
-        "link": "https://docs.meilisearch.com/errors#invalid_search_filter"
+        "link": "https://docs.meilisearch.com/errors#invalid_document_filter"
       },
       "duration": "[duration]",
       "enqueuedAt": "[date]",
@@ -748,4 +760,27 @@ async fn fetch_document_by_filter() {
       "link": "https://docs.meilisearch.com/errors#invalid_document_filter"
     }
     "###);
+
+    let (response, code) = index.get_document_by_filter(json!({ "filter": "cool doggo" })).await;
+    snapshot!(code, @"400 Bad Request");
+    snapshot!(json_string!(response), @r###"
+    {
+      "message": "Was expecting an operation `=`, `!=`, `>=`, `>`, `<=`, `<`, `IN`, `NOT IN`, `TO`, `EXISTS`, `NOT EXISTS`, `IS NULL`, `IS NOT NULL`, `IS EMPTY`, `IS NOT EMPTY`, `_geoRadius`, or `_geoBoundingBox` at `cool doggo`.\n1:11 cool doggo",
+      "code": "invalid_document_filter",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#invalid_document_filter"
+    }
+    "###);
+
+    let (response, code) =
+        index.get_document_by_filter(json!({ "filter": "doggo = bernese" })).await;
+    snapshot!(code, @"400 Bad Request");
+    snapshot!(json_string!(response), @r###"
+    {
+      "message": "Attribute `doggo` is not filterable. Available filterable attributes are: `color`.\n1:6 doggo = bernese",
+      "code": "invalid_document_filter",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#invalid_document_filter"
+    }
+    "###);
 }

meilisearch/tests/search/errors.rs

@@ -946,7 +946,7 @@ async fn sort_unset_ranking_rule() {
     index.wait_task(1).await;
 
     let expected_response = json!({
-        "message": "The sort ranking rule must be specified in the ranking rules settings to use the sort parameter at search time.",
+        "message": "You must specify where `sort` is listed in the rankingRules setting to use the sort parameter at search time.",
         "code": "invalid_search_sort",
         "type": "invalid_request",
         "link": "https://docs.meilisearch.com/errors#invalid_search_sort"

meilisearch/tests/tasks/errors.rs

@@ -97,7 +97,7 @@ async fn task_bad_types() {
     snapshot!(code, @"400 Bad Request");
     snapshot!(json_string!(response), @r###"
     {
-      "message": "Invalid value in parameter `types`: `doggo` is not a valid task type. Available types are `documentAdditionOrUpdate`, `documentDeletion`, `documentDeletionByFilter`, `settingsUpdate`, `indexCreation`, `indexDeletion`, `indexUpdate`, `indexSwap`, `taskCancelation`, `taskDeletion`, `dumpCreation`, `snapshotCreation`.",
+      "message": "Invalid value in parameter `types`: `doggo` is not a valid task type. Available types are `documentAdditionOrUpdate`, `documentDeletion`, `settingsUpdate`, `indexCreation`, `indexDeletion`, `indexUpdate`, `indexSwap`, `taskCancelation`, `taskDeletion`, `dumpCreation`, `snapshotCreation`.",
       "code": "invalid_task_types",
       "type": "invalid_request",
       "link": "https://docs.meilisearch.com/errors#invalid_task_types"
@@ -108,7 +108,7 @@ async fn task_bad_types() {
     snapshot!(code, @"400 Bad Request");
     snapshot!(json_string!(response), @r###"
     {
-      "message": "Invalid value in parameter `types`: `doggo` is not a valid task type. Available types are `documentAdditionOrUpdate`, `documentDeletion`, `documentDeletionByFilter`, `settingsUpdate`, `indexCreation`, `indexDeletion`, `indexUpdate`, `indexSwap`, `taskCancelation`, `taskDeletion`, `dumpCreation`, `snapshotCreation`.",
+      "message": "Invalid value in parameter `types`: `doggo` is not a valid task type. Available types are `documentAdditionOrUpdate`, `documentDeletion`, `settingsUpdate`, `indexCreation`, `indexDeletion`, `indexUpdate`, `indexSwap`, `taskCancelation`, `taskDeletion`, `dumpCreation`, `snapshotCreation`.",
       "code": "invalid_task_types",
       "type": "invalid_request",
       "link": "https://docs.meilisearch.com/errors#invalid_task_types"
@@ -119,7 +119,7 @@ async fn task_bad_types() {
     snapshot!(code, @"400 Bad Request");
     snapshot!(json_string!(response), @r###"
     {
-      "message": "Invalid value in parameter `types`: `doggo` is not a valid task type. Available types are `documentAdditionOrUpdate`, `documentDeletion`, `documentDeletionByFilter`, `settingsUpdate`, `indexCreation`, `indexDeletion`, `indexUpdate`, `indexSwap`, `taskCancelation`, `taskDeletion`, `dumpCreation`, `snapshotCreation`.",
+      "message": "Invalid value in parameter `types`: `doggo` is not a valid task type. Available types are `documentAdditionOrUpdate`, `documentDeletion`, `settingsUpdate`, `indexCreation`, `indexDeletion`, `indexUpdate`, `indexSwap`, `taskCancelation`, `taskDeletion`, `dumpCreation`, `snapshotCreation`.",
       "code": "invalid_task_types",
       "type": "invalid_request",
       "link": "https://docs.meilisearch.com/errors#invalid_task_types"

meilisearch/tests/tasks/mod.rs

@@ -413,7 +413,7 @@ async fn test_summarized_document_addition_or_update() {
 }
 
 #[actix_web::test]
-async fn test_summarized_delete_batch() {
+async fn test_summarized_delete_documents_by_batch() {
     let server = Server::new().await;
     let index = server.index("test");
     index.delete_batch(vec![1, 2, 3]).await;
@@ -430,7 +430,8 @@ async fn test_summarized_delete_batch() {
       "canceledBy": null,
       "details": {
         "providedIds": 3,
-        "deletedDocuments": 0
+        "deletedDocuments": 0,
+        "originalFilter": null
       },
       "error": {
         "message": "Index `test` not found.",
@@ -460,7 +461,8 @@ async fn test_summarized_delete_batch() {
       "canceledBy": null,
       "details": {
         "providedIds": 1,
-        "deletedDocuments": 0
+        "deletedDocuments": 0,
+        "originalFilter": null
       },
       "error": null,
       "duration": "[duration]",
@@ -472,7 +474,100 @@ async fn test_summarized_delete_batch() {
 }
 
 #[actix_web::test]
-async fn test_summarized_delete_document() {
+async fn test_summarized_delete_documents_by_filter() {
+    let server = Server::new().await;
+    let index = server.index("test");
+
+    index.delete_document_by_filter(json!({ "filter": "doggo = bernese" })).await;
+    index.wait_task(0).await;
+    let (task, _) = index.get_task(0).await;
+    assert_json_snapshot!(task,
+        { ".duration" => "[duration]", ".enqueuedAt" => "[date]", ".startedAt" => "[date]", ".finishedAt" => "[date]" },
+        @r###"
+    {
+      "uid": 0,
+      "indexUid": "test",
+      "status": "failed",
+      "type": "documentDeletion",
+      "canceledBy": null,
+      "details": {
+        "providedIds": 0,
+        "deletedDocuments": 0,
+        "originalFilter": "\"doggo = bernese\""
+      },
+      "error": {
+        "message": "Index `test` not found.",
+        "code": "index_not_found",
+        "type": "invalid_request",
+        "link": "https://docs.meilisearch.com/errors#index_not_found"
+      },
+      "duration": "[duration]",
+      "enqueuedAt": "[date]",
+      "startedAt": "[date]",
+      "finishedAt": "[date]"
+    }
+    "###);
+
+    index.create(None).await;
+    index.delete_document_by_filter(json!({ "filter": "doggo = bernese" })).await;
+    index.wait_task(2).await;
+    let (task, _) = index.get_task(2).await;
+    assert_json_snapshot!(task,
+        { ".duration" => "[duration]", ".enqueuedAt" => "[date]", ".startedAt" => "[date]", ".finishedAt" => "[date]" },
+        @r###"
+    {
+      "uid": 2,
+      "indexUid": "test",
+      "status": "failed",
+      "type": "documentDeletion",
+      "canceledBy": null,
+      "details": {
+        "providedIds": 0,
+        "deletedDocuments": 0,
+        "originalFilter": "\"doggo = bernese\""
+      },
+      "error": {
+        "message": "Attribute `doggo` is not filterable. This index does not have configured filterable attributes.\n1:6 doggo = bernese",
+        "code": "invalid_document_filter",
+        "type": "invalid_request",
+        "link": "https://docs.meilisearch.com/errors#invalid_document_filter"
+      },
+      "duration": "[duration]",
+      "enqueuedAt": "[date]",
+      "startedAt": "[date]",
+      "finishedAt": "[date]"
+    }
+    "###);
+
+    index.update_settings(json!({ "filterableAttributes": ["doggo"] })).await;
+    index.delete_document_by_filter(json!({ "filter": "doggo = bernese" })).await;
+    index.wait_task(4).await;
+    let (task, _) = index.get_task(4).await;
+    assert_json_snapshot!(task,
+        { ".duration" => "[duration]", ".enqueuedAt" => "[date]", ".startedAt" => "[date]", ".finishedAt" => "[date]" },
+        @r###"
+    {
+      "uid": 4,
+      "indexUid": "test",
+      "status": "succeeded",
+      "type": "documentDeletion",
+      "canceledBy": null,
+      "details": {
+        "providedIds": 0,
+        "deletedDocuments": 0,
+        "originalFilter": "\"doggo = bernese\""
+      },
+      "error": null,
+      "duration": "[duration]",
+      "enqueuedAt": "[date]",
+      "startedAt": "[date]",
+      "finishedAt": "[date]"
+    }
+    "###);
+}
+
+#[actix_web::test]
+async fn test_summarized_delete_document_by_id() {
     let server = Server::new().await;
     let index = server.index("test");
     index.delete_document(1).await;
@@ -489,7 +584,8 @@ async fn test_summarized_delete_document() {
       "canceledBy": null,
       "details": {
         "providedIds": 1,
-        "deletedDocuments": 0
+        "deletedDocuments": 0,
+        "originalFilter": null
       },
       "error": {
         "message": "Index `test` not found.",
@@ -519,7 +615,8 @@ async fn test_summarized_delete_document() {
       "canceledBy": null,
       "details": {
         "providedIds": 1,
-        "deletedDocuments": 0
+        "deletedDocuments": 0,
+        "originalFilter": null
       },
       "error": null,
       "duration": "[duration]",

milli/Cargo.toml

@@ -25,8 +25,13 @@ flatten-serde-json = { path = "../flatten-serde-json" }
 fst = "0.4.7"
 fxhash = "0.2.1"
 geoutils = "0.5.1"
-grenad = { version = "0.4.4", default-features = false, features = ["tempfile"] }
+grenad = { version = "0.4.4", default-features = false, features = [
-heed = { git = "https://github.com/meilisearch/heed", tag = "v0.12.5", default-features = false, features = ["lmdb", "sync-read-txn"] }
+    "tempfile",
+] }
+heed = { git = "https://github.com/meilisearch/heed", tag = "v0.12.6", default-features = false, features = [
+    "lmdb",
+    "sync-read-txn",
+] }
 json-depth-checker = { path = "../json-depth-checker" }
 levenshtein_automata = { version = "0.2.1", features = ["fst_automaton"] }
 memmap2 = "0.5.10"
@@ -44,7 +49,12 @@ smallvec = "1.10.0"
 smartstring = "1.0.1"
 tempfile = "3.5.0"
 thiserror = "1.0.40"
-time = { version = "0.3.20", features = ["serde-well-known", "formatting", "parsing", "macros"] }
+time = { version = "0.3.20", features = [
+    "serde-well-known",
+    "formatting",
+    "parsing",
+    "macros",
+] }
 uuid = { version = "1.3.1", features = ["v4"] }
 
 filter-parser = { path = "../filter-parser" }
@@ -65,9 +75,6 @@ maplit = "1.0.2"
 md5 = "0.7.0"
 rand = { version = "0.8.5", features = ["small_rng"] }
 
-[target.'cfg(fuzzing)'.dev-dependencies]
-fuzzcheck = "0.12.1"
-
 [features]
 all-tokenizations = ["charabia/default"]
 

milli/src/documents/mod.rs

@@ -111,7 +111,6 @@ pub enum Error {
     Io(#[from] io::Error),
 }
 
-#[cfg(test)]
 pub fn objects_from_json_value(json: serde_json::Value) -> Vec<crate::Object> {
     let documents = match json {
         object @ serde_json::Value::Object(_) => vec![object],
@@ -141,7 +140,6 @@ macro_rules! documents {
     }};
 }
 
-#[cfg(test)]
 pub fn documents_batch_reader_from_objects(
     objects: impl IntoIterator<Item = Object>,
 ) -> DocumentsBatchReader<std::io::Cursor<Vec<u8>>> {

milli/src/error.rs

@@ -126,7 +126,7 @@ only composed of alphanumeric characters (a-z A-Z 0-9), hyphens (-) and undersco
     InvalidSortableAttribute { field: String, valid_fields: BTreeSet<String> },
     #[error("{}", HeedError::BadOpenOptions)]
     InvalidLmdbOpenOptions,
-    #[error("The sort ranking rule must be specified in the ranking rules settings to use the sort parameter at search time.")]
+    #[error("You must specify where `sort` is listed in the rankingRules setting to use the sort parameter at search time.")]
     SortRankingRuleMissing,
     #[error("The database file is in an invalid state.")]
     InvalidStoreFile,

milli/src/external_documents_ids.rs

@@ -106,8 +106,11 @@ impl<'a> ExternalDocumentsIds<'a> {
         map
     }
 
-    fn merge_soft_into_hard(&mut self) -> fst::Result<()> {
+    /// Return an fst of the combined hard and soft deleted ID.
-        if self.soft.len() >= self.hard.len() / 2 {
+    pub fn to_fst<'b>(&'b self) -> fst::Result<Cow<'b, fst::Map<Cow<'a, [u8]>>>> {
+        if self.soft.is_empty() {
+            return Ok(Cow::Borrowed(&self.hard));
+        }
         let union_op = self.hard.op().add(&self.soft).r#union();
 
         let mut iter = union_op.into_stream();
@@ -121,7 +124,12 @@ impl<'a> ExternalDocumentsIds<'a> {
 
         drop(iter);
 
-            self.hard = new_hard_builder.into_map().map_data(Cow::Owned)?;
+        Ok(Cow::Owned(new_hard_builder.into_map().map_data(Cow::Owned)?))
+    }
+
+    fn merge_soft_into_hard(&mut self) -> fst::Result<()> {
+        if self.soft.len() >= self.hard.len() / 2 {
+            self.hard = self.to_fst()?.into_owned();
             self.soft = fst::Map::default().map_data(Cow::Owned)?;
         }
 

milli/src/heed_codec/roaring_bitmap/cbo_roaring_bitmap_codec.rs

@@ -49,7 +49,7 @@ impl CboRoaringBitmapCodec {
         } else {
             // Otherwise, it means we used the classic RoaringBitmapCodec and
             // that the header takes threshold integers.
-            RoaringBitmap::deserialize_from(bytes)
+            RoaringBitmap::deserialize_unchecked_from(bytes)
         }
     }
 
@@ -69,7 +69,7 @@ impl CboRoaringBitmapCodec {
                     vec.push(integer);
                 }
             } else {
-                roaring |= RoaringBitmap::deserialize_from(bytes.as_ref())?;
+                roaring |= RoaringBitmap::deserialize_unchecked_from(bytes.as_ref())?;
             }
         }
 

milli/src/heed_codec/roaring_bitmap/roaring_bitmap_codec.rs

@@ -8,7 +8,7 @@ impl heed::BytesDecode<'_> for RoaringBitmapCodec {
     type DItem = RoaringBitmap;
 
     fn bytes_decode(bytes: &[u8]) -> Option<Self::DItem> {
-        RoaringBitmap::deserialize_from(bytes).ok()
+        RoaringBitmap::deserialize_unchecked_from(bytes).ok()
     }
 }
 

milli/src/index.rs

@@ -21,10 +21,9 @@ use crate::heed_codec::facet::{
 };
 use crate::heed_codec::{ScriptLanguageCodec, StrBEU16Codec, StrRefCodec};
 use crate::{
-    default_criteria, BEU32StrCodec, BoRoaringBitmapCodec, CboRoaringBitmapCodec, Criterion,
+    default_criteria, CboRoaringBitmapCodec, Criterion, DocumentId, ExternalDocumentsIds,
-    DocumentId, ExternalDocumentsIds, FacetDistribution, FieldDistribution, FieldId,
+    FacetDistribution, FieldDistribution, FieldId, FieldIdWordCountCodec, GeoPoint, ObkvCodec,
-    FieldIdWordCountCodec, GeoPoint, ObkvCodec, Result, RoaringBitmapCodec, RoaringBitmapLenCodec,
+    Result, RoaringBitmapCodec, RoaringBitmapLenCodec, Search, U8StrStrCodec, BEU16, BEU32,
-    Search, U8StrStrCodec, BEU16, BEU32,
 };
 
 pub const DEFAULT_MIN_WORD_LEN_ONE_TYPO: u8 = 5;
@@ -111,9 +110,6 @@ pub struct Index {
     /// A prefix of word and all the documents ids containing this prefix, from attributes for which typos are not allowed.
     pub exact_word_prefix_docids: Database<Str, RoaringBitmapCodec>,
 
-    /// Maps a word and a document id (u32) to all the positions where the given word appears.
-    pub docid_word_positions: Database<BEU32StrCodec, BoRoaringBitmapCodec>,
-
     /// Maps the proximity between a pair of words with all the docids where this relation appears.
     pub word_pair_proximity_docids: Database<U8StrStrCodec, CboRoaringBitmapCodec>,
     /// Maps the proximity between a pair of word and prefix with all the docids where this relation appears.
@@ -170,33 +166,45 @@ impl Index {
         unsafe { options.flag(Flags::MdbAlwaysFreePages) };
 
         let env = options.open(path)?;
-        let main = env.create_poly_database(Some(MAIN))?;
+        let mut wtxn = env.write_txn()?;
-        let word_docids = env.create_database(Some(WORD_DOCIDS))?;
+        let main = env.create_poly_database(&mut wtxn, Some(MAIN))?;
-        let exact_word_docids = env.create_database(Some(EXACT_WORD_DOCIDS))?;
+        let word_docids = env.create_database(&mut wtxn, Some(WORD_DOCIDS))?;
-        let word_prefix_docids = env.create_database(Some(WORD_PREFIX_DOCIDS))?;
+        let exact_word_docids = env.create_database(&mut wtxn, Some(EXACT_WORD_DOCIDS))?;
-        let exact_word_prefix_docids = env.create_database(Some(EXACT_WORD_PREFIX_DOCIDS))?;
+        let word_prefix_docids = env.create_database(&mut wtxn, Some(WORD_PREFIX_DOCIDS))?;
-        let docid_word_positions = env.create_database(Some(DOCID_WORD_POSITIONS))?;
+        let exact_word_prefix_docids =
-        let word_pair_proximity_docids = env.create_database(Some(WORD_PAIR_PROXIMITY_DOCIDS))?;
+            env.create_database(&mut wtxn, Some(EXACT_WORD_PREFIX_DOCIDS))?;
-        let script_language_docids = env.create_database(Some(SCRIPT_LANGUAGE_DOCIDS))?;
+        let word_pair_proximity_docids =
+            env.create_database(&mut wtxn, Some(WORD_PAIR_PROXIMITY_DOCIDS))?;
+        let script_language_docids =
+            env.create_database(&mut wtxn, Some(SCRIPT_LANGUAGE_DOCIDS))?;
         let word_prefix_pair_proximity_docids =
-            env.create_database(Some(WORD_PREFIX_PAIR_PROXIMITY_DOCIDS))?;
+            env.create_database(&mut wtxn, Some(WORD_PREFIX_PAIR_PROXIMITY_DOCIDS))?;
         let prefix_word_pair_proximity_docids =
-            env.create_database(Some(PREFIX_WORD_PAIR_PROXIMITY_DOCIDS))?;
+            env.create_database(&mut wtxn, Some(PREFIX_WORD_PAIR_PROXIMITY_DOCIDS))?;
-        let word_position_docids = env.create_database(Some(WORD_POSITION_DOCIDS))?;
+        let word_position_docids = env.create_database(&mut wtxn, Some(WORD_POSITION_DOCIDS))?;
-        let word_fid_docids = env.create_database(Some(WORD_FIELD_ID_DOCIDS))?;
+        let word_fid_docids = env.create_database(&mut wtxn, Some(WORD_FIELD_ID_DOCIDS))?;
-        let field_id_word_count_docids = env.create_database(Some(FIELD_ID_WORD_COUNT_DOCIDS))?;
+        let field_id_word_count_docids =
-        let word_prefix_position_docids = env.create_database(Some(WORD_PREFIX_POSITION_DOCIDS))?;
+            env.create_database(&mut wtxn, Some(FIELD_ID_WORD_COUNT_DOCIDS))?;
-        let word_prefix_fid_docids = env.create_database(Some(WORD_PREFIX_FIELD_ID_DOCIDS))?;
+        let word_prefix_position_docids =
-        let facet_id_f64_docids = env.create_database(Some(FACET_ID_F64_DOCIDS))?;
+            env.create_database(&mut wtxn, Some(WORD_PREFIX_POSITION_DOCIDS))?;
-        let facet_id_string_docids = env.create_database(Some(FACET_ID_STRING_DOCIDS))?;
+        let word_prefix_fid_docids =
-        let facet_id_exists_docids = env.create_database(Some(FACET_ID_EXISTS_DOCIDS))?;
+            env.create_database(&mut wtxn, Some(WORD_PREFIX_FIELD_ID_DOCIDS))?;
-        let facet_id_is_null_docids = env.create_database(Some(FACET_ID_IS_NULL_DOCIDS))?;
+        let facet_id_f64_docids = env.create_database(&mut wtxn, Some(FACET_ID_F64_DOCIDS))?;
-        let facet_id_is_empty_docids = env.create_database(Some(FACET_ID_IS_EMPTY_DOCIDS))?;
+        let facet_id_string_docids =
+            env.create_database(&mut wtxn, Some(FACET_ID_STRING_DOCIDS))?;
+        let facet_id_exists_docids =
+            env.create_database(&mut wtxn, Some(FACET_ID_EXISTS_DOCIDS))?;
+        let facet_id_is_null_docids =
+            env.create_database(&mut wtxn, Some(FACET_ID_IS_NULL_DOCIDS))?;
+        let facet_id_is_empty_docids =
+            env.create_database(&mut wtxn, Some(FACET_ID_IS_EMPTY_DOCIDS))?;
 
-        let field_id_docid_facet_f64s = env.create_database(Some(FIELD_ID_DOCID_FACET_F64S))?;
+        let field_id_docid_facet_f64s =
+            env.create_database(&mut wtxn, Some(FIELD_ID_DOCID_FACET_F64S))?;
         let field_id_docid_facet_strings =
-            env.create_database(Some(FIELD_ID_DOCID_FACET_STRINGS))?;
+            env.create_database(&mut wtxn, Some(FIELD_ID_DOCID_FACET_STRINGS))?;
-        let documents = env.create_database(Some(DOCUMENTS))?;
+        let documents = env.create_database(&mut wtxn, Some(DOCUMENTS))?;
+        wtxn.commit()?;
 
         Index::set_creation_dates(&env, main, created_at, updated_at)?;
 
@@ -207,7 +215,6 @@ impl Index {
             exact_word_docids,
             word_prefix_docids,
             exact_word_prefix_docids,
-            docid_word_positions,
             word_pair_proximity_docids,
             script_language_docids,
             word_prefix_pair_proximity_docids,
@@ -1459,9 +1466,9 @@ pub(crate) mod tests {
 
         db_snap!(index, field_distribution,
             @r###"
-        age              1     
+        age              1      |
-        id               2     
+        id               2      |
-        name             2     
+        name             2      |
         "###
         );
 
@@ -1479,9 +1486,9 @@ pub(crate) mod tests {
 
         db_snap!(index, field_distribution,
             @r###"
-        age              1     
+        age              1      |
-        id               2     
+        id               2      |
-        name             2     
+        name             2      |
         "###
         );
 
@@ -1495,9 +1502,9 @@ pub(crate) mod tests {
 
         db_snap!(index, field_distribution,
             @r###"
-        has_dog          1     
+        has_dog          1      |
-        id               2     
+        id               2      |
-        name             2     
+        name             2      |
         "###
         );
     }

milli/src/lib.rs

@@ -5,52 +5,6 @@
 #[global_allocator]
 pub static ALLOC: mimalloc::MiMalloc = mimalloc::MiMalloc;
 
-// #[cfg(test)]
-// pub mod allocator {
-//     use std::alloc::{GlobalAlloc, System};
-//     use std::sync::atomic::{self, AtomicI64};
-
-//     #[global_allocator]
-//     pub static ALLOC: CountingAlloc = CountingAlloc {
-//         max_resident: AtomicI64::new(0),
-//         resident: AtomicI64::new(0),
-//         allocated: AtomicI64::new(0),
-//     };
-
-//     pub struct CountingAlloc {
-//         pub max_resident: AtomicI64,
-//         pub resident: AtomicI64,
-//         pub allocated: AtomicI64,
-//     }
-//     unsafe impl GlobalAlloc for CountingAlloc {
-//         unsafe fn alloc(&self, layout: std::alloc::Layout) -> *mut u8 {
-//             self.allocated.fetch_add(layout.size() as i64, atomic::Ordering::SeqCst);
-//             let old_resident =
-//                 self.resident.fetch_add(layout.size() as i64, atomic::Ordering::SeqCst);
-
-//             let resident = old_resident + layout.size() as i64;
-//             self.max_resident.fetch_max(resident, atomic::Ordering::SeqCst);
-
-//             // if layout.size() > 1_000_000 {
-//             //     eprintln!(
-//             //         "allocating {} with new resident size: {resident}",
-//             //         layout.size() / 1_000_000
-//             //     );
-//             //     // let trace = std::backtrace::Backtrace::capture();
-//             //     // let t = trace.to_string();
-//             //     // eprintln!("{t}");
-//             // }
-
-//             System.alloc(layout)
-//         }
-
-//         unsafe fn dealloc(&self, ptr: *mut u8, layout: std::alloc::Layout) {
-//             self.resident.fetch_sub(layout.size() as i64, atomic::Ordering::Relaxed);
-//             System.dealloc(ptr, layout)
-//         }
-//     }
-// }
-
 #[macro_use]
 pub mod documents;
 

milli/src/search/new/distinct.rs

@@ -26,7 +26,6 @@ pub fn apply_distinct_rule(
     ctx: &mut SearchContext,
     field_id: u16,
     candidates: &RoaringBitmap,
-    // TODO: add a universe here, such that the `excluded` are a subset of the universe?
 ) -> Result<DistinctOutput> {
     let mut excluded = RoaringBitmap::new();
     let mut remaining = RoaringBitmap::new();

milli/src/search/new/exact_attribute.rs

@@ -206,7 +206,7 @@ impl State {
             )?;
             intersection &= &candidates;
             if !intersection.is_empty() {
-                // TODO: although not really worth it in terms of performance,
+                // Although not really worth it in terms of performance,
                 // if would be good to put this in cache for the sake of consistency
                 let candidates_with_exact_word_count = if count_all_positions < u8::MAX as usize {
                     ctx.index

milli/src/search/new/graph_based_ranking_rule.rs

@@ -46,7 +46,7 @@ use super::logger::SearchLogger;
 use super::query_graph::QueryNode;
 use super::ranking_rule_graph::{
     ConditionDocIdsCache, DeadEndsCache, ExactnessGraph, FidGraph, PositionGraph, ProximityGraph,
-    RankingRuleGraph, RankingRuleGraphTrait, TypoGraph,
+    RankingRuleGraph, RankingRuleGraphTrait, TypoGraph, WordsGraph,
 };
 use super::small_bitmap::SmallBitmap;
 use super::{QueryGraph, RankingRule, RankingRuleOutput, SearchContext};
@@ -54,6 +54,12 @@ use crate::search::new::query_term::LocatedQueryTermSubset;
 use crate::search::new::ranking_rule_graph::PathVisitor;
 use crate::{Result, TermsMatchingStrategy};
 
+pub type Words = GraphBasedRankingRule<WordsGraph>;
+impl GraphBasedRankingRule<WordsGraph> {
+    pub fn new(terms_matching_strategy: TermsMatchingStrategy) -> Self {
+        Self::new_with_id("words".to_owned(), Some(terms_matching_strategy))
+    }
+}
 pub type Proximity = GraphBasedRankingRule<ProximityGraph>;
 impl GraphBasedRankingRule<ProximityGraph> {
     pub fn new(terms_matching_strategy: Option<TermsMatchingStrategy>) -> Self {

milli/src/search/new/interner.rs

@@ -32,7 +32,7 @@ impl<T> Interned<T> {
 #[derive(Clone)]
 pub struct DedupInterner<T> {
     stable_store: Vec<T>,
-    lookup: FxHashMap<T, Interned<T>>, // TODO: Arc
+    lookup: FxHashMap<T, Interned<T>>,
 }
 impl<T> Default for DedupInterner<T> {
     fn default() -> Self {

milli/src/search/new/limits.rs

@@ -1,5 +1,4 @@
 /// Maximum number of tokens we consider in a single search.
-// TODO: Loic, find proper value here so we don't overflow the interner.
 pub const MAX_TOKEN_COUNT: usize = 1_000;
 
 /// Maximum number of prefixes that can be derived from a single word.

milli/src/search/new/logger/visual.rs

@@ -4,7 +4,6 @@ use std::io::{BufWriter, Write};
 use std::path::{Path, PathBuf};
 use std::time::Instant;
 
-// use rand::random;
 use roaring::RoaringBitmap;
 
 use crate::search::new::interner::Interned;
@@ -13,6 +12,7 @@ use crate::search::new::query_term::LocatedQueryTermSubset;
 use crate::search::new::ranking_rule_graph::{
     Edge, FidCondition, FidGraph, PositionCondition, PositionGraph, ProximityCondition,
     ProximityGraph, RankingRuleGraph, RankingRuleGraphTrait, TypoCondition, TypoGraph,
+    WordsCondition, WordsGraph,
 };
 use crate::search::new::ranking_rules::BoxRankingRule;
 use crate::search::new::{QueryGraph, QueryNode, RankingRule, SearchContext, SearchLogger};
@@ -24,11 +24,12 @@ pub enum SearchEvents {
     RankingRuleSkipBucket { ranking_rule_idx: usize, bucket_len: u64 },
     RankingRuleEndIteration { ranking_rule_idx: usize, universe_len: u64 },
     ExtendResults { new: Vec<u32> },
-    WordsGraph { query_graph: QueryGraph },
     ProximityGraph { graph: RankingRuleGraph<ProximityGraph> },
     ProximityPaths { paths: Vec<Vec<Interned<ProximityCondition>>> },
     TypoGraph { graph: RankingRuleGraph<TypoGraph> },
     TypoPaths { paths: Vec<Vec<Interned<TypoCondition>>> },
+    WordsGraph { graph: RankingRuleGraph<WordsGraph> },
+    WordsPaths { paths: Vec<Vec<Interned<WordsCondition>>> },
     FidGraph { graph: RankingRuleGraph<FidGraph> },
     FidPaths { paths: Vec<Vec<Interned<FidCondition>>> },
     PositionGraph { graph: RankingRuleGraph<PositionGraph> },
@@ -139,8 +140,11 @@ impl SearchLogger<QueryGraph> for VisualSearchLogger {
         let Some(location) = self.location.last() else { return };
         match location {
             Location::Words => {
-                if let Some(query_graph) = state.downcast_ref::<QueryGraph>() {
+                if let Some(graph) = state.downcast_ref::<RankingRuleGraph<WordsGraph>>() {
-                    self.events.push(SearchEvents::WordsGraph { query_graph: query_graph.clone() });
+                    self.events.push(SearchEvents::WordsGraph { graph: graph.clone() });
+                }
+                if let Some(paths) = state.downcast_ref::<Vec<Vec<Interned<WordsCondition>>>>() {
+                    self.events.push(SearchEvents::WordsPaths { paths: paths.clone() });
                 }
             }
             Location::Typo => {
@@ -329,7 +333,6 @@ impl<'ctx> DetailedLoggerFinish<'ctx> {
             SearchEvents::ExtendResults { new } => {
                 self.write_extend_results(new)?;
             }
-            SearchEvents::WordsGraph { query_graph } => self.write_words_graph(query_graph)?,
             SearchEvents::ProximityGraph { graph } => self.write_rr_graph(&graph)?,
             SearchEvents::ProximityPaths { paths } => {
                 self.write_rr_graph_paths::<ProximityGraph>(paths)?;
@@ -338,6 +341,10 @@ impl<'ctx> DetailedLoggerFinish<'ctx> {
             SearchEvents::TypoPaths { paths } => {
                 self.write_rr_graph_paths::<TypoGraph>(paths)?;
             }
+            SearchEvents::WordsGraph { graph } => self.write_rr_graph(&graph)?,
+            SearchEvents::WordsPaths { paths } => {
+                self.write_rr_graph_paths::<WordsGraph>(paths)?;
+            }
             SearchEvents::FidGraph { graph } => self.write_rr_graph(&graph)?,
             SearchEvents::FidPaths { paths } => {
                 self.write_rr_graph_paths::<FidGraph>(paths)?;
@@ -455,7 +462,7 @@ fill: \"#B6E2D3\"
                 shape: class
                 max_nbr_typo: {}",
                     term_subset.description(ctx),
-                    term_subset.max_nbr_typos(ctx)
+                    term_subset.max_typo_cost(ctx)
                 )?;
 
                 for w in term_subset.all_single_words_except_prefix_db(ctx)? {
@@ -482,13 +489,6 @@ fill: \"#B6E2D3\"
         }
         Ok(())
     }
-    fn write_words_graph(&mut self, qg: QueryGraph) -> Result<()> {
-        self.make_new_file_for_internal_state_if_needed()?;
-
-        self.write_query_graph(&qg)?;
-
-        Ok(())
-    }
     fn write_rr_graph<R: RankingRuleGraphTrait>(
         &mut self,
         graph: &RankingRuleGraph<R>,

milli/src/search/new/mod.rs

@@ -15,11 +15,7 @@ mod resolve_query_graph;
 mod small_bitmap;
 
 mod exact_attribute;
-// TODO: documentation + comments
-// implementation is currently an adaptation of the previous implementation to fit with the new model
 mod sort;
-// TODO: documentation + comments
-mod words;
 
 #[cfg(test)]
 mod tests;
@@ -43,10 +39,10 @@ use ranking_rules::{
 use resolve_query_graph::{compute_query_graph_docids, PhraseDocIdsCache};
 use roaring::RoaringBitmap;
 use sort::Sort;
-use words::Words;
 
 use self::geo_sort::GeoSort;
 pub use self::geo_sort::Strategy as GeoSortStrategy;
+use self::graph_based_ranking_rule::Words;
 use self::interner::Interned;
 use crate::search::new::distinct::apply_distinct_rule;
 use crate::{AscDesc, DocumentId, Filter, Index, Member, Result, TermsMatchingStrategy, UserError};
@@ -202,6 +198,11 @@ fn get_ranking_rules_for_query_graph_search<'ctx>(
     let mut sorted_fields = HashSet::new();
     let mut geo_sorted = false;
 
+    // Don't add the `words` ranking rule if the term matching strategy is `All`
+    if matches!(terms_matching_strategy, TermsMatchingStrategy::All) {
+        words = true;
+    }
+
     let mut ranking_rules: Vec<BoxRankingRule<QueryGraph>> = vec![];
     let settings_ranking_rules = ctx.index.criteria(ctx.txn)?;
     for rr in settings_ranking_rules {
@@ -397,8 +398,8 @@ pub fn execute_search(
         None
     };
     let bucket_sort_output = if let Some(query_terms) = query_terms {
-        let graph = QueryGraph::from_query(ctx, &query_terms)?;
+        let (graph, new_located_query_terms) = QueryGraph::from_query(ctx, &query_terms)?;
-        located_query_terms = Some(query_terms);
+        located_query_terms = Some(new_located_query_terms);
 
         let ranking_rules = get_ranking_rules_for_query_graph_search(
             ctx,

milli/src/search/new/query_graph.rs

@@ -88,29 +88,33 @@ pub struct QueryGraph {
 }
 
 impl QueryGraph {
-    /// Build the query graph from the parsed user search query.
+    /// Build the query graph from the parsed user search query, return an updated list of the located query terms
+    /// which contains ngrams.
     pub fn from_query(
         ctx: &mut SearchContext,
-        // NOTE: the terms here must be consecutive
+        // The terms here must be consecutive
         terms: &[LocatedQueryTerm],
-    ) -> Result<QueryGraph> {
+    ) -> Result<(QueryGraph, Vec<LocatedQueryTerm>)> {
+        let mut new_located_query_terms = terms.to_vec();
+
         let nbr_typos = number_of_typos_allowed(ctx)?;
 
         let mut nodes_data: Vec<QueryNodeData> = vec![QueryNodeData::Start, QueryNodeData::End];
         let root_node = 0;
         let end_node = 1;
 
-        // TODO: we could consider generalizing to 4,5,6,7,etc. ngrams
+        // Ee could consider generalizing to 4,5,6,7,etc. ngrams
         let (mut prev2, mut prev1, mut prev0): (Vec<u16>, Vec<u16>, Vec<u16>) =
             (vec![], vec![], vec![root_node]);
 
         let original_terms_len = terms.len();
         for term_idx in 0..original_terms_len {
             let mut new_nodes = vec![];
+
             let new_node_idx = add_node(
                 &mut nodes_data,
                 QueryNodeData::Term(LocatedQueryTermSubset {
-                    term_subset: QueryTermSubset::full(Interned::from_raw(term_idx as u16)),
+                    term_subset: QueryTermSubset::full(terms[term_idx].value),
                     positions: terms[term_idx].positions.clone(),
                     term_ids: term_idx as u8..=term_idx as u8,
                 }),
@@ -121,6 +125,7 @@ impl QueryGraph {
                 if let Some(ngram) =
                     query_term::make_ngram(ctx, &terms[term_idx - 1..=term_idx], &nbr_typos)?
                 {
+                    new_located_query_terms.push(ngram.clone());
                     let ngram_idx = add_node(
                         &mut nodes_data,
                         QueryNodeData::Term(LocatedQueryTermSubset {
@@ -136,6 +141,7 @@ impl QueryGraph {
                 if let Some(ngram) =
                     query_term::make_ngram(ctx, &terms[term_idx - 2..=term_idx], &nbr_typos)?
                 {
+                    new_located_query_terms.push(ngram.clone());
                     let ngram_idx = add_node(
                         &mut nodes_data,
                         QueryNodeData::Term(LocatedQueryTermSubset {
@@ -167,7 +173,7 @@ impl QueryGraph {
         let mut graph = QueryGraph { root_node, end_node, nodes };
         graph.build_initial_edges();
 
-        Ok(graph)
+        Ok((graph, new_located_query_terms))
     }
 
     /// Remove the given nodes, connecting all their predecessors to all their successors.

milli/src/search/new/query_term/compute_derivations.rs

@@ -28,14 +28,14 @@ pub enum ZeroOrOneTypo {
 impl Interned<QueryTerm> {
     pub fn compute_fully_if_needed(self, ctx: &mut SearchContext) -> Result<()> {
         let s = ctx.term_interner.get_mut(self);
-        if s.max_nbr_typos <= 1 && s.one_typo.is_uninit() {
+        if s.max_levenshtein_distance <= 1 && s.one_typo.is_uninit() {
             assert!(s.two_typo.is_uninit());
             // Initialize one_typo subterm even if max_nbr_typo is 0 because of split words
             self.initialize_one_typo_subterm(ctx)?;
             let s = ctx.term_interner.get_mut(self);
             assert!(s.one_typo.is_init());
             s.two_typo = Lazy::Init(TwoTypoTerm::default());
-        } else if s.max_nbr_typos > 1 && s.two_typo.is_uninit() {
+        } else if s.max_levenshtein_distance > 1 && s.two_typo.is_uninit() {
             assert!(s.two_typo.is_uninit());
             self.initialize_one_and_two_typo_subterm(ctx)?;
             let s = ctx.term_interner.get_mut(self);
@@ -185,7 +185,7 @@ pub fn partially_initialized_term_from_word(
                 original: ctx.word_interner.insert(word.to_owned()),
                 ngram_words: None,
                 is_prefix: false,
-                max_nbr_typos: 0,
+                max_levenshtein_distance: 0,
                 zero_typo: <_>::default(),
                 one_typo: Lazy::Init(<_>::default()),
                 two_typo: Lazy::Init(<_>::default()),
@@ -256,7 +256,7 @@ pub fn partially_initialized_term_from_word(
     Ok(QueryTerm {
         original: word_interned,
         ngram_words: None,
-        max_nbr_typos: max_typo,
+        max_levenshtein_distance: max_typo,
         is_prefix,
         zero_typo,
         one_typo: Lazy::Uninit,
@@ -275,7 +275,16 @@ fn find_split_words(ctx: &mut SearchContext, word: &str) -> Result<Option<Intern
 impl Interned<QueryTerm> {
     fn initialize_one_typo_subterm(self, ctx: &mut SearchContext) -> Result<()> {
         let self_mut = ctx.term_interner.get_mut(self);
-        let QueryTerm { original, is_prefix, one_typo, max_nbr_typos, .. } = self_mut;
+
+        let allows_split_words = self_mut.allows_split_words();
+        let QueryTerm {
+            original,
+            is_prefix,
+            one_typo,
+            max_levenshtein_distance: max_nbr_typos,
+            ..
+        } = self_mut;
+
         let original = *original;
         let is_prefix = *is_prefix;
         // let original_str = ctx.word_interner.get(*original).to_owned();
@@ -300,13 +309,17 @@ impl Interned<QueryTerm> {
             })?;
         }
 
+        let split_words = if allows_split_words {
             let original_str = ctx.word_interner.get(original).to_owned();
-        let split_words = find_split_words(ctx, original_str.as_str())?;
+            find_split_words(ctx, original_str.as_str())?
+        } else {
+            None
+        };
 
         let self_mut = ctx.term_interner.get_mut(self);
 
         // Only add the split words to the derivations if:
-        // 1. the term is not an ngram; OR
+        // 1. the term is neither an ngram nor a phrase; OR
         // 2. the term is an ngram, but the split words are different from the ngram's component words
         let split_words = if let Some((ngram_words, split_words)) =
             self_mut.ngram_words.as_ref().zip(split_words.as_ref())
@@ -328,7 +341,13 @@ impl Interned<QueryTerm> {
     }
     fn initialize_one_and_two_typo_subterm(self, ctx: &mut SearchContext) -> Result<()> {
         let self_mut = ctx.term_interner.get_mut(self);
-        let QueryTerm { original, is_prefix, two_typo, max_nbr_typos, .. } = self_mut;
+        let QueryTerm {
+            original,
+            is_prefix,
+            two_typo,
+            max_levenshtein_distance: max_nbr_typos,
+            ..
+        } = self_mut;
         let original_str = ctx.word_interner.get(*original).to_owned();
         if two_typo.is_init() {
             return Ok(());

milli/src/search/new/query_term/mod.rs

@@ -43,7 +43,7 @@ pub struct QueryTermSubset {
 pub struct QueryTerm {
     original: Interned<String>,
     ngram_words: Option<Vec<Interned<String>>>,
-    max_nbr_typos: u8,
+    max_levenshtein_distance: u8,
     is_prefix: bool,
     zero_typo: ZeroTypoTerm,
     // May not be computed yet
@@ -132,7 +132,6 @@ impl QueryTermSubset {
         if full_query_term.ngram_words.is_some() {
             return None;
         }
-        // TODO: included in subset
         if let Some(phrase) = full_query_term.zero_typo.phrase {
             self.zero_typo_subset.contains_phrase(phrase).then_some(ExactTerm::Phrase(phrase))
         } else if let Some(word) = full_query_term.zero_typo.exact {
@@ -182,7 +181,6 @@ impl QueryTermSubset {
         let word = match &self.zero_typo_subset {
             NTypoTermSubset::All => Some(use_prefix_db),
             NTypoTermSubset::Subset { words, phrases: _ } => {
-                // TODO: use a subset of prefix words instead
                 if words.contains(&use_prefix_db) {
                     Some(use_prefix_db)
                 } else {
@@ -204,7 +202,6 @@ impl QueryTermSubset {
         ctx: &mut SearchContext,
     ) -> Result<BTreeSet<Word>> {
         let mut result = BTreeSet::default();
-        // TODO: a compute_partially funtion
         if !self.one_typo_subset.is_empty() || !self.two_typo_subset.is_empty() {
             self.original.compute_fully_if_needed(ctx)?;
         }
@@ -300,7 +297,6 @@ impl QueryTermSubset {
         let mut result = BTreeSet::default();
 
         if !self.one_typo_subset.is_empty() {
-            // TODO: compute less than fully if possible
             self.original.compute_fully_if_needed(ctx)?;
         }
         let original = ctx.term_interner.get_mut(self.original);
@@ -342,10 +338,16 @@ impl QueryTermSubset {
         }
         None
     }
-    pub fn max_nbr_typos(&self, ctx: &SearchContext) -> u8 {
+    pub fn max_typo_cost(&self, ctx: &SearchContext) -> u8 {
         let t = ctx.term_interner.get(self.original);
-        match t.max_nbr_typos {
+        match t.max_levenshtein_distance {
-            0 => 0,
+            0 => {
+                if t.allows_split_words() {
+                    1
+                } else {
+                    0
+                }
+            }
             1 => {
                 if self.one_typo_subset.is_empty() {
                     0
@@ -438,6 +440,9 @@ impl QueryTerm {
 
         self.zero_typo.is_empty() && one_typo.is_empty() && two_typo.is_empty()
     }
+    fn allows_split_words(&self) -> bool {
+        self.zero_typo.phrase.is_none()
+    }
 }
 
 impl Interned<QueryTerm> {

milli/src/search/new/query_term/parse_query.rs

@@ -77,13 +77,9 @@ pub fn located_query_terms_from_tokens(
                 }
             }
             TokenKind::Separator(separator_kind) => {
-                match separator_kind {
+                // add penalty for hard separators
-                    SeparatorKind::Hard => {
+                if let SeparatorKind::Hard = separator_kind {
-                        position += 1;
+                    position = position.wrapping_add(7);
-                    }
-                    SeparatorKind::Soft => {
-                        position += 0;
-                    }
                 }
 
                 phrase = 'phrase: {
@@ -143,7 +139,6 @@ pub fn number_of_typos_allowed<'ctx>(
     let min_len_one_typo = ctx.index.min_word_len_one_typo(ctx.txn)?;
     let min_len_two_typos = ctx.index.min_word_len_two_typos(ctx.txn)?;
 
-    // TODO: should `exact_words` also disable prefix search, ngrams, split words, or synonyms?
     let exact_words = ctx.index.exact_words(ctx.txn)?;
 
     Ok(Box::new(move |word: &str| {
@@ -217,7 +212,7 @@ pub fn make_ngram(
         original: ngram_str_interned,
         ngram_words: Some(words_interned),
         is_prefix,
-        max_nbr_typos,
+        max_levenshtein_distance: max_nbr_typos,
         zero_typo: term.zero_typo,
         one_typo: Lazy::Uninit,
         two_typo: Lazy::Uninit,
@@ -254,8 +249,6 @@ impl PhraseBuilder {
         } else {
             // token has kind Word
             let word = ctx.word_interner.insert(token.lemma().to_string());
-            // TODO: in a phrase, check that every word exists
-            // otherwise return an empty term
             self.words.push(Some(word));
         }
     }
@@ -271,7 +264,7 @@ impl PhraseBuilder {
                 QueryTerm {
                     original: ctx.word_interner.insert(phrase_desc),
                     ngram_words: None,
-                    max_nbr_typos: 0,
+                    max_levenshtein_distance: 0,
                     is_prefix: false,
                     zero_typo: ZeroTypoTerm {
                         phrase: Some(phrase),
@@ -288,3 +281,36 @@ impl PhraseBuilder {
         })
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use charabia::TokenizerBuilder;
+
+    use super::*;
+    use crate::index::tests::TempIndex;
+
+    fn temp_index_with_documents() -> TempIndex {
+        let temp_index = TempIndex::new();
+        temp_index
+            .add_documents(documents!([
+                { "id": 1, "name": "split this world westfali westfalia the Ŵôřlḑôle" },
+                { "id": 2, "name": "Westfália" },
+                { "id": 3, "name": "Ŵôřlḑôle" },
+            ]))
+            .unwrap();
+        temp_index
+    }
+
+    #[test]
+    fn start_with_hard_separator() -> Result<()> {
+        let tokenizer = TokenizerBuilder::new().build();
+        let tokens = tokenizer.tokenize(".");
+        let index = temp_index_with_documents();
+        let rtxn = index.read_txn()?;
+        let mut ctx = SearchContext::new(&index, &rtxn);
+        // panics with `attempt to add with overflow` before <https://github.com/meilisearch/meilisearch/issues/3785>
+        let located_query_terms = located_query_terms_from_tokens(&mut ctx, tokens, None)?;
+        assert!(located_query_terms.is_empty());
+        Ok(())
+    }
+}

milli/src/search/new/ranking_rule_graph/cheapest_paths.rs

@@ -1,5 +1,48 @@
-#![allow(clippy::too_many_arguments)]
+/** Implements a "PathVisitor" which finds all paths of a certain cost
+from the START to END node of a ranking rule graph.
 
+A path is a list of conditions. A condition is the data associated with
+an edge, given by the ranking rule. Some edges don't have a condition associated
+with them, they are "unconditional". These kinds of edges are used to "skip" a node.
+
+The algorithm uses a depth-first search. It benefits from two main optimisations:
+- The list of all possible costs to go from any node to the END node is precomputed
+- The `DeadEndsCache` reduces the number of valid paths drastically, by making some edges
+untraversable depending on what other edges were selected.
+
+These two optimisations are meant to avoid traversing edges that wouldn't lead
+to a valid path. In practically all cases, we avoid the exponential complexity
+that is inherent to depth-first search in a large ranking rule graph.
+
+The DeadEndsCache is a sort of prefix tree which associates a list of forbidden
+conditions to a list of traversed conditions.
+For example, the DeadEndsCache could say the following:
+- Immediately, from the start, the conditions `[a,b]` are forbidden
+    - if we take the condition `c`, then the conditions `[e]` are also forbidden
+        - and if after that, we take `f`, then `[h,i]` are also forbidden
+            - etc.
+    - if we take `g`, then `[f]` is also forbidden
+        - etc.
+    - etc.
+As we traverse the graph, we also traverse the `DeadEndsCache` and keep a list of forbidden
+conditions in memory. Then, we know to avoid all edges which have a condition that is forbidden.
+
+When a path is found from START to END, we give it to the `visit` closure.
+This closure takes a mutable reference to the `DeadEndsCache`. This means that
+the caller can update this cache. Therefore, we must handle the case where the
+DeadEndsCache has been updated. This means potentially backtracking up to the point
+where the traversed conditions are all allowed by the new DeadEndsCache.
+
+The algorithm also implements the `TermsMatchingStrategy` logic.
+Some edges are augmented with a list of "nodes_to_skip". Skipping
+a node means "reaching this node through an unconditional edge". If we have
+already traversed (ie. not skipped) a node that is in this list, then we know that we
+can't traverse this edge. Otherwise, we traverse the edge but make sure to skip any
+future node that was present in the "nodes_to_skip" list.
+
+The caller can decide to stop the path finding algorithm
+by returning a `ControlFlow::Break` from the `visit` closure.
+*/
 use std::collections::{BTreeSet, VecDeque};
 use std::iter::FromIterator;
 use std::ops::ControlFlow;
@@ -12,30 +55,41 @@ use crate::search::new::query_graph::QueryNode;
 use crate::search::new::small_bitmap::SmallBitmap;
 use crate::Result;
 
+/// Closure which processes a path found by the `PathVisitor`
 type VisitFn<'f, G> = &'f mut dyn FnMut(
+    // the path as a list of conditions
     &[Interned<<G as RankingRuleGraphTrait>::Condition>],
     &mut RankingRuleGraph<G>,
+    // a mutable reference to the DeadEndsCache, to update it in case the given
+    // path doesn't resolve to any valid document ids
     &mut DeadEndsCache<<G as RankingRuleGraphTrait>::Condition>,
 ) -> Result<ControlFlow<()>>;
 
+/// A structure which is kept but not updated during the traversal of the graph.
+/// It can however be updated by the `visit` closure once a valid path has been found.
 struct VisitorContext<'a, G: RankingRuleGraphTrait> {
     graph: &'a mut RankingRuleGraph<G>,
     all_costs_from_node: &'a MappedInterner<QueryNode, Vec<u64>>,
     dead_ends_cache: &'a mut DeadEndsCache<G::Condition>,
 }
 
+/// The internal state of the traversal algorithm
 struct VisitorState<G: RankingRuleGraphTrait> {
+    /// Budget from the current node to the end node
     remaining_cost: u64,
-
+    /// Previously visited conditions, in order.
     path: Vec<Interned<G::Condition>>,
-
+    /// Previously visited conditions, as an efficient and compact set.
     visited_conditions: SmallBitmap<G::Condition>,
+    /// Previously visited (ie not skipped) nodes, as an efficient and compact set.
     visited_nodes: SmallBitmap<QueryNode>,
-
+    /// The conditions that cannot be visited anymore
     forbidden_conditions: SmallBitmap<G::Condition>,
-    forbidden_conditions_to_nodes: SmallBitmap<QueryNode>,
+    /// The nodes that cannot be visited anymore (they must be skipped)
+    nodes_to_skip: SmallBitmap<QueryNode>,
 }
 
+/// See module documentation
 pub struct PathVisitor<'a, G: RankingRuleGraphTrait> {
     state: VisitorState<G>,
     ctx: VisitorContext<'a, G>,
@@ -56,14 +110,13 @@ impl<'a, G: RankingRuleGraphTrait> PathVisitor<'a, G> {
                 forbidden_conditions: SmallBitmap::for_interned_values_in(
                     &graph.conditions_interner,
                 ),
-                forbidden_conditions_to_nodes: SmallBitmap::for_interned_values_in(
+                nodes_to_skip: SmallBitmap::for_interned_values_in(&graph.query_graph.nodes),
-                    &graph.query_graph.nodes,
-                ),
             },
             ctx: VisitorContext { graph, all_costs_from_node, dead_ends_cache },
         }
     }
 
+    /// See module documentation
     pub fn visit_paths(mut self, visit: VisitFn<G>) -> Result<()> {
         let _ =
             self.state.visit_node(self.ctx.graph.query_graph.root_node, visit, &mut self.ctx)?;
@@ -72,22 +125,31 @@ impl<'a, G: RankingRuleGraphTrait> PathVisitor<'a, G> {
 }
 
 impl<G: RankingRuleGraphTrait> VisitorState<G> {
+    /// Visits a node: traverse all its valid conditional and unconditional edges.
+    ///
+    /// Returns ControlFlow::Break if the path finding algorithm should stop.
+    /// Returns whether a valid path was found from this node otherwise.
     fn visit_node(
         &mut self,
         from_node: Interned<QueryNode>,
         visit: VisitFn<G>,
         ctx: &mut VisitorContext<G>,
     ) -> Result<ControlFlow<(), bool>> {
+        // any valid path will be found from this point
+        // if a valid path was found, then we know that the DeadEndsCache may have been updated,
+        // and we will need to do more work to potentially backtrack
         let mut any_valid = false;
 
         let edges = ctx.graph.edges_of_node.get(from_node).clone();
         for edge_idx in edges.iter() {
+            // could be none if the edge was deleted
             let Some(edge) = ctx.graph.edges_store.get(edge_idx).clone() else { continue };
 
             if self.remaining_cost < edge.cost as u64 {
                 continue;
             }
             self.remaining_cost -= edge.cost as u64;
+
             let cf = match edge.condition {
                 Some(condition) => self.visit_condition(
                     condition,
@@ -119,6 +181,10 @@ impl<G: RankingRuleGraphTrait> VisitorState<G> {
         Ok(ControlFlow::Continue(any_valid))
     }
 
+    /// Visits an unconditional edge.
+    ///
+    /// Returns ControlFlow::Break if the path finding algorithm should stop.
+    /// Returns whether a valid path was found from this node otherwise.
     fn visit_no_condition(
         &mut self,
         dest_node: Interned<QueryNode>,
@@ -134,20 +200,29 @@ impl<G: RankingRuleGraphTrait> VisitorState<G> {
         {
             return Ok(ControlFlow::Continue(false));
         }
+        // We've reached the END node!
         if dest_node == ctx.graph.query_graph.end_node {
             let control_flow = visit(&self.path, ctx.graph, ctx.dead_ends_cache)?;
+            // We could change the return type of the visit closure such that the caller
+            // tells us whether the dead ends cache was updated or not.
+            // Alternatively, maybe the DeadEndsCache should have a generation number
+            // to it, so that we don't need to play with these booleans at all.
             match control_flow {
                 ControlFlow::Continue(_) => Ok(ControlFlow::Continue(true)),
                 ControlFlow::Break(_) => Ok(ControlFlow::Break(())),
             }
         } else {
-            let old_fbct = self.forbidden_conditions_to_nodes.clone();
+            let old_fbct = self.nodes_to_skip.clone();
-            self.forbidden_conditions_to_nodes.union(edge_new_nodes_to_skip);
+            self.nodes_to_skip.union(edge_new_nodes_to_skip);
             let cf = self.visit_node(dest_node, visit, ctx)?;
-            self.forbidden_conditions_to_nodes = old_fbct;
+            self.nodes_to_skip = old_fbct;
             Ok(cf)
         }
     }
+    /// Visits a conditional edge.
+    ///
+    /// Returns ControlFlow::Break if the path finding algorithm should stop.
+    /// Returns whether a valid path was found from this node otherwise.
     fn visit_condition(
         &mut self,
         condition: Interned<G::Condition>,
@@ -159,7 +234,7 @@ impl<G: RankingRuleGraphTrait> VisitorState<G> {
         assert!(dest_node != ctx.graph.query_graph.end_node);
 
         if self.forbidden_conditions.contains(condition)
-            || self.forbidden_conditions_to_nodes.contains(dest_node)
+            || self.nodes_to_skip.contains(dest_node)
             || edge_new_nodes_to_skip.intersects(&self.visited_nodes)
         {
             return Ok(ControlFlow::Continue(false));
@@ -180,19 +255,19 @@ impl<G: RankingRuleGraphTrait> VisitorState<G> {
         self.visited_nodes.insert(dest_node);
         self.visited_conditions.insert(condition);
 
-        let old_fc = self.forbidden_conditions.clone();
+        let old_forb_cond = self.forbidden_conditions.clone();
         if let Some(next_forbidden) =
             ctx.dead_ends_cache.forbidden_conditions_after_prefix(self.path.iter().copied())
         {
             self.forbidden_conditions.union(&next_forbidden);
         }
-        let old_fctn = self.forbidden_conditions_to_nodes.clone();
+        let old_nodes_to_skip = self.nodes_to_skip.clone();
-        self.forbidden_conditions_to_nodes.union(edge_new_nodes_to_skip);
+        self.nodes_to_skip.union(edge_new_nodes_to_skip);
 
         let cf = self.visit_node(dest_node, visit, ctx)?;
 
-        self.forbidden_conditions_to_nodes = old_fctn;
+        self.nodes_to_skip = old_nodes_to_skip;
-        self.forbidden_conditions = old_fc;
+        self.forbidden_conditions = old_forb_cond;
 
         self.visited_conditions.remove(condition);
         self.visited_nodes.remove(dest_node);
@@ -205,18 +280,12 @@ impl<G: RankingRuleGraphTrait> VisitorState<G> {
 impl<G: RankingRuleGraphTrait> RankingRuleGraph<G> {
     pub fn find_all_costs_to_end(&self) -> MappedInterner<QueryNode, Vec<u64>> {
         let mut costs_to_end = self.query_graph.nodes.map(|_| vec![]);
-        let mut enqueued = SmallBitmap::new(self.query_graph.nodes.len());
-
-        let mut node_stack = VecDeque::new();
 
+        self.traverse_breadth_first_backward(self.query_graph.end_node, |cur_node| {
+            if cur_node == self.query_graph.end_node {
                 *costs_to_end.get_mut(self.query_graph.end_node) = vec![0];
-
+                return;
-        for prev_node in self.query_graph.nodes.get(self.query_graph.end_node).predecessors.iter() {
-            node_stack.push_back(prev_node);
-            enqueued.insert(prev_node);
             }
-
-        while let Some(cur_node) = node_stack.pop_front() {
             let mut self_costs = Vec::<u64>::new();
 
             let cur_node_edges = &self.edges_of_node.get(cur_node);
@@ -232,13 +301,7 @@ impl<G: RankingRuleGraphTrait> RankingRuleGraph<G> {
             self_costs.dedup();
 
             *costs_to_end.get_mut(cur_node) = self_costs;
-            for prev_node in self.query_graph.nodes.get(cur_node).predecessors.iter() {
+        });
-                if !enqueued.contains(prev_node) {
-                    node_stack.push_back(prev_node);
-                    enqueued.insert(prev_node);
-                }
-            }
-        }
         costs_to_end
     }
 
@@ -247,17 +310,12 @@ impl<G: RankingRuleGraphTrait> RankingRuleGraph<G> {
         node_with_removed_outgoing_conditions: Interned<QueryNode>,
         costs: &mut MappedInterner<QueryNode, Vec<u64>>,
     ) {
-        let mut enqueued = SmallBitmap::new(self.query_graph.nodes.len());
+        // Traverse the graph backward from the target node, recomputing the cost for each of its predecessors.
-        let mut node_stack = VecDeque::new();
+        // We first check that no other node is contributing the same total cost to a predecessor before removing
-
+        // the cost from the predecessor.
-        enqueued.insert(node_with_removed_outgoing_conditions);
+        self.traverse_breadth_first_backward(node_with_removed_outgoing_conditions, |cur_node| {
-        node_stack.push_back(node_with_removed_outgoing_conditions);
-
-        'main_loop: while let Some(cur_node) = node_stack.pop_front() {
             let mut costs_to_remove = FxHashSet::default();
-            for c in costs.get(cur_node) {
+            costs_to_remove.extend(costs.get(cur_node).iter().copied());
-                costs_to_remove.insert(*c);
-            }
 
             let cur_node_edges = &self.edges_of_node.get(cur_node);
             for edge_idx in cur_node_edges.iter() {
@@ -265,22 +323,75 @@ impl<G: RankingRuleGraphTrait> RankingRuleGraph<G> {
                 for cost in costs.get(edge.dest_node).iter() {
                     costs_to_remove.remove(&(*cost + edge.cost as u64));
                     if costs_to_remove.is_empty() {
-                        continue 'main_loop;
+                        return;
                     }
                 }
             }
             if costs_to_remove.is_empty() {
-                continue 'main_loop;
+                return;
             }
             let mut new_costs = BTreeSet::from_iter(costs.get(cur_node).iter().copied());
             for c in costs_to_remove {
                 new_costs.remove(&c);
             }
             *costs.get_mut(cur_node) = new_costs.into_iter().collect();
+        });
+    }
 
+    /// Traverse the graph backwards from the given node such that every time
+    /// a node is visited, we are guaranteed that all its successors either:
+    /// 1. have already been visited; OR
+    /// 2. were not reachable from the given node
+    pub fn traverse_breadth_first_backward(
+        &self,
+        from: Interned<QueryNode>,
+        mut visit: impl FnMut(Interned<QueryNode>),
+    ) {
+        let mut reachable = SmallBitmap::for_interned_values_in(&self.query_graph.nodes);
+        {
+            // go backward to get the set of all reachable nodes from the given node
+            // the nodes that are not reachable will be set as `visited`
+            let mut stack = VecDeque::new();
+            let mut enqueued = SmallBitmap::for_interned_values_in(&self.query_graph.nodes);
+            enqueued.insert(from);
+            stack.push_back(from);
+            while let Some(n) = stack.pop_front() {
+                if reachable.contains(n) {
+                    continue;
+                }
+                reachable.insert(n);
+                for prev_node in self.query_graph.nodes.get(n).predecessors.iter() {
+                    if !enqueued.contains(prev_node) && !reachable.contains(prev_node) {
+                        stack.push_back(prev_node);
+                        enqueued.insert(prev_node);
+                    }
+                }
+            }
+        };
+        let mut unreachable_or_visited =
+            SmallBitmap::for_interned_values_in(&self.query_graph.nodes);
+        for (n, _) in self.query_graph.nodes.iter() {
+            if !reachable.contains(n) {
+                unreachable_or_visited.insert(n);
+            }
+        }
+
+        let mut enqueued = SmallBitmap::for_interned_values_in(&self.query_graph.nodes);
+        let mut stack = VecDeque::new();
+
+        enqueued.insert(from);
+        stack.push_back(from);
+
+        while let Some(cur_node) = stack.pop_front() {
+            if !self.query_graph.nodes.get(cur_node).successors.is_subset(&unreachable_or_visited) {
+                stack.push_back(cur_node);
+                continue;
+            }
+            unreachable_or_visited.insert(cur_node);
+            visit(cur_node);
             for prev_node in self.query_graph.nodes.get(cur_node).predecessors.iter() {
-                if !enqueued.contains(prev_node) {
+                if !enqueued.contains(prev_node) && !unreachable_or_visited.contains(prev_node) {
-                    node_stack.push_back(prev_node);
+                    stack.push_back(prev_node);
                     enqueued.insert(prev_node);
                 }
             }

milli/src/search/new/ranking_rule_graph/condition_docids_cache.rs

@@ -9,12 +9,8 @@ use crate::search::new::query_term::LocatedQueryTermSubset;
 use crate::search::new::SearchContext;
 use crate::Result;
 
-// TODO: give a generation to each universe, then be able to get the exact
-// delta of docids between two universes of different generations!
-
 /// A cache storing the document ids associated with each ranking rule edge
 pub struct ConditionDocIdsCache<G: RankingRuleGraphTrait> {
-    // TOOD: should be a mapped interner?
     pub cache: FxHashMap<Interned<G::Condition>, ComputedCondition>,
     _phantom: PhantomData<G>,
 }
@@ -54,7 +50,7 @@ impl<G: RankingRuleGraphTrait> ConditionDocIdsCache<G> {
         }
         let condition = graph.conditions_interner.get_mut(interned_condition);
         let computed = G::resolve_condition(ctx, condition, universe)?;
-        // TODO: if computed.universe_len != universe.len() ?
+        // Can we put an assert here for computed.universe_len == universe.len() ?
         let _ = self.cache.insert(interned_condition, computed);
         let computed = &self.cache[&interned_condition];
         Ok(computed)

milli/src/search/new/ranking_rule_graph/dead_ends_cache.rs

@@ -2,6 +2,7 @@ use crate::search::new::interner::{FixedSizeInterner, Interned};
 use crate::search::new::small_bitmap::SmallBitmap;
 
 pub struct DeadEndsCache<T> {
+    // conditions and next could/should be part of the same vector
     conditions: Vec<Interned<T>>,
     next: Vec<Self>,
     pub forbidden: SmallBitmap<T>,
@@ -27,7 +28,7 @@ impl<T> DeadEndsCache<T> {
         self.forbidden.insert(condition);
     }
 
-    pub fn advance(&mut self, condition: Interned<T>) -> Option<&mut Self> {
+    fn advance(&mut self, condition: Interned<T>) -> Option<&mut Self> {
         if let Some(idx) = self.conditions.iter().position(|c| *c == condition) {
             Some(&mut self.next[idx])
         } else {

milli/src/search/new/ranking_rule_graph/fid/mod.rs

@@ -69,14 +69,9 @@ impl RankingRuleGraphTrait for FidGraph {
 
         let mut edges = vec![];
         for fid in all_fields {
-            // TODO: We can improve performances and relevancy by storing
-            //       the term subsets associated to each field ids fetched.
             edges.push((
-                fid as u32 * term.term_ids.len() as u32, // TODO improve the fid score i.e. fid^10.
+                fid as u32 * term.term_ids.len() as u32,
-                conditions_interner.insert(FidCondition {
+                conditions_interner.insert(FidCondition { term: term.clone(), fid }),
-                    term: term.clone(), // TODO remove this ugly clone
-                    fid,
-                }),
             ));
         }
 

milli/src/search/new/ranking_rule_graph/mod.rs

@@ -20,6 +20,8 @@ mod position;
 mod proximity;
 /// Implementation of the `typo` ranking rule
 mod typo;
+/// Implementation of the `words` ranking rule
+mod words;
 
 use std::collections::BTreeSet;
 use std::hash::Hash;
@@ -33,6 +35,7 @@ pub use position::{PositionCondition, PositionGraph};
 pub use proximity::{ProximityCondition, ProximityGraph};
 use roaring::RoaringBitmap;
 pub use typo::{TypoCondition, TypoGraph};
+pub use words::{WordsCondition, WordsGraph};
 
 use super::interner::{DedupInterner, FixedSizeInterner, Interned, MappedInterner};
 use super::query_term::LocatedQueryTermSubset;

milli/src/search/new/ranking_rule_graph/position/mod.rs

@@ -94,14 +94,9 @@ impl RankingRuleGraphTrait for PositionGraph {
         let mut edges = vec![];
 
         for (cost, positions) in positions_for_costs {
-            // TODO: We can improve performances and relevancy by storing
-            //       the term subsets associated to each position fetched
             edges.push((
                 cost,
-                conditions_interner.insert(PositionCondition {
+                conditions_interner.insert(PositionCondition { term: term.clone(), positions }),
-                    term: term.clone(), // TODO remove this ugly clone
-                    positions,
-                }),
             ));
         }
 
@@ -111,23 +106,16 @@ impl RankingRuleGraphTrait for PositionGraph {
 
 fn cost_from_position(sum_positions: u32) -> u32 {
     match sum_positions {
-        0 | 1 | 2 | 3 => sum_positions,
+        0 => 0,
-        4 | 5 => 4,
+        1 => 1,
-        6 | 7 => 5,
+        2..=4 => 2,
-        8 | 9 => 6,
+        5..=7 => 3,
-        10 | 11 => 7,
+        8..=11 => 4,
-        12 | 13 => 8,
+        12..=16 => 5,
-        14 | 15 => 9,
+        17..=24 => 6,
-        16 | 17..=24 => 10,
+        25..=64 => 7,
-        25..=32 => 11,
+        65..=256 => 8,
-        33..=64 => 12,
+        257..=1024 => 9,
-        65..=128 => 13,
+        _ => 10,
-        129..=256 => 14,
-        257..=512 => 15,
-        513..=1024 => 16,
-        1025..=2048 => 17,
-        2049..=4096 => 18,
-        4097..=8192 => 19,
-        _ => 20,
     }
 }

milli/src/search/new/ranking_rule_graph/proximity/compute_docids.rs

@@ -65,13 +65,6 @@ pub fn compute_docids(
         }
     }
 
-    // TODO: add safeguard in case the cartesian product is too large!
-    // even if we restrict the word derivations to a maximum of 100, the size of the
-    // caterisan product could reach a maximum of 10_000 derivations, which is way too much.
-    // Maybe prioritise the product of zero typo derivations, then the product of zero-typo/one-typo
-    // + one-typo/zero-typo, then one-typo/one-typo, then ... until an arbitrary limit has been
-    // reached
-
     for (left_phrase, left_word) in last_words_of_term_derivations(ctx, &left_term.term_subset)? {
         // Before computing the edges, check that the left word and left phrase
         // aren't disjoint with the universe, but only do it if there is more than
@@ -111,8 +104,6 @@ pub fn compute_docids(
     Ok(ComputedCondition {
         docids,
         universe_len: universe.len(),
-        // TODO: think about whether we want to reduce the subset,
-        // we probably should!
         start_term_subset: Some(left_term.clone()),
         end_term_subset: right_term.clone(),
     })
@@ -203,12 +194,7 @@ fn compute_non_prefix_edges(
             *docids |= new_docids;
         }
     }
-    if backward_proximity >= 1
+    if backward_proximity >= 1 && left_phrase.is_none() && right_phrase.is_none() {
-            // TODO: for now, we don't do any swapping when either term is a phrase
-            // but maybe we should. We'd need to look at the first/last word of the phrase
-            // depending on the context.
-            && left_phrase.is_none() && right_phrase.is_none()
-    {
         if let Some(new_docids) =
             ctx.get_db_word_pair_proximity_docids(word2, word1, backward_proximity)?
         {

milli/src/search/new/ranking_rule_graph/typo/mod.rs

@@ -50,7 +50,7 @@ impl RankingRuleGraphTrait for TypoGraph {
         // 3-gram -> equivalent to 2 typos
         let base_cost = if term.term_ids.len() == 1 { 0 } else { term.term_ids.len() as u32 };
 
-        for nbr_typos in 0..=term.term_subset.max_nbr_typos(ctx) {
+        for nbr_typos in 0..=term.term_subset.max_typo_cost(ctx) {
             let mut term = term.clone();
             match nbr_typos {
                 0 => {

milli/src/search/new/ranking_rule_graph/words/mod.rs

@@ -0,0 +1,49 @@
+use roaring::RoaringBitmap;
+
+use super::{ComputedCondition, RankingRuleGraphTrait};
+use crate::search::new::interner::{DedupInterner, Interned};
+use crate::search::new::query_term::LocatedQueryTermSubset;
+use crate::search::new::resolve_query_graph::compute_query_term_subset_docids;
+use crate::search::new::SearchContext;
+use crate::Result;
+
+#[derive(Clone, PartialEq, Eq, Hash)]
+pub struct WordsCondition {
+    term: LocatedQueryTermSubset,
+}
+
+pub enum WordsGraph {}
+
+impl RankingRuleGraphTrait for WordsGraph {
+    type Condition = WordsCondition;
+
+    fn resolve_condition(
+        ctx: &mut SearchContext,
+        condition: &Self::Condition,
+        universe: &RoaringBitmap,
+    ) -> Result<ComputedCondition> {
+        let WordsCondition { term, .. } = condition;
+        // maybe compute_query_term_subset_docids should accept a universe as argument
+        let mut docids = compute_query_term_subset_docids(ctx, &term.term_subset)?;
+        docids &= universe;
+
+        Ok(ComputedCondition {
+            docids,
+            universe_len: universe.len(),
+            start_term_subset: None,
+            end_term_subset: term.clone(),
+        })
+    }
+
+    fn build_edges(
+        _ctx: &mut SearchContext,
+        conditions_interner: &mut DedupInterner<Self::Condition>,
+        _from: Option<&LocatedQueryTermSubset>,
+        to_term: &LocatedQueryTermSubset,
+    ) -> Result<Vec<(u32, Interned<Self::Condition>)>> {
+        Ok(vec![(
+            to_term.term_ids.len() as u32,
+            conditions_interner.insert(WordsCondition { term: to_term.clone() }),
+        )])
+    }
+}

milli/src/search/new/resolve_query_graph.rs

@@ -33,8 +33,6 @@ pub fn compute_query_term_subset_docids(
     ctx: &mut SearchContext,
     term: &QueryTermSubset,
 ) -> Result<RoaringBitmap> {
-    // TODO Use the roaring::MultiOps trait
-
     let mut docids = RoaringBitmap::new();
     for word in term.all_single_words_except_prefix_db(ctx)? {
         if let Some(word_docids) = ctx.word_docids(word)? {
@@ -59,8 +57,6 @@ pub fn compute_query_term_subset_docids_within_field_id(
     term: &QueryTermSubset,
     fid: u16,
 ) -> Result<RoaringBitmap> {
-    // TODO Use the roaring::MultiOps trait
-
     let mut docids = RoaringBitmap::new();
     for word in term.all_single_words_except_prefix_db(ctx)? {
         if let Some(word_fid_docids) = ctx.get_db_word_fid_docids(word.interned(), fid)? {
@@ -71,7 +67,6 @@ pub fn compute_query_term_subset_docids_within_field_id(
     for phrase in term.all_phrases(ctx)? {
         // There may be false positives when resolving a phrase, so we're not
         // guaranteed that all of its words are within a single fid.
-        // TODO: fix this?
         if let Some(word) = phrase.words(ctx).iter().flatten().next() {
             if let Some(word_fid_docids) = ctx.get_db_word_fid_docids(*word, fid)? {
                 docids |= ctx.get_phrase_docids(phrase)? & word_fid_docids;
@@ -95,7 +90,6 @@ pub fn compute_query_term_subset_docids_within_position(
     term: &QueryTermSubset,
     position: u16,
 ) -> Result<RoaringBitmap> {
-    // TODO Use the roaring::MultiOps trait
     let mut docids = RoaringBitmap::new();
     for word in term.all_single_words_except_prefix_db(ctx)? {
         if let Some(word_position_docids) =
@@ -108,7 +102,6 @@ pub fn compute_query_term_subset_docids_within_position(
     for phrase in term.all_phrases(ctx)? {
         // It's difficult to know the expected position of the words in the phrase,
         // so instead we just check the first one.
-        // TODO: fix this?
         if let Some(word) = phrase.words(ctx).iter().flatten().next() {
             if let Some(word_position_docids) = ctx.get_db_word_position_docids(*word, position)? {
                 docids |= ctx.get_phrase_docids(phrase)? & word_position_docids
@@ -132,9 +125,6 @@ pub fn compute_query_graph_docids(
     q: &QueryGraph,
     universe: &RoaringBitmap,
 ) -> Result<RoaringBitmap> {
-    // TODO: there must be a faster way to compute this big
-    // roaring bitmap expression
-
     let mut nodes_resolved = SmallBitmap::for_interned_values_in(&q.nodes);
     let mut path_nodes_docids = q.nodes.map(|_| RoaringBitmap::new());
 

milli/src/search/new/sort.rs

@@ -141,10 +141,6 @@ impl<'ctx, Query: RankingRuleQueryTrait> RankingRule<'ctx, Query> for Sort<'ctx,
         universe: &RoaringBitmap,
     ) -> Result<Option<RankingRuleOutput<Query>>> {
         let iter = self.iter.as_mut().unwrap();
-        // TODO: we should make use of the universe in the function below
-        // good for correctness, but ideally iter.next_bucket would take the current universe into account,
-        // as right now it could return buckets that don't intersect with the universe, meaning we will make many
-        // unneeded calls.
         if let Some(mut bucket) = iter.next_bucket()? {
             bucket.candidates &= universe;
             Ok(Some(bucket))

milli/src/search/new/tests/attribute_position.rs

@@ -138,7 +138,7 @@ fn test_attribute_position_simple() {
     s.terms_matching_strategy(TermsMatchingStrategy::All);
     s.query("quick brown");
     let SearchResult { documents_ids, .. } = s.execute().unwrap();
-    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[10, 11, 12, 13, 3, 4, 2, 1, 0, 6, 8, 7, 9, 5]");
+    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[10, 11, 12, 13, 2, 3, 4, 1, 0, 6, 8, 7, 9, 5]");
 }
 #[test]
 fn test_attribute_position_repeated() {
@@ -163,7 +163,7 @@ fn test_attribute_position_different_fields() {
     s.terms_matching_strategy(TermsMatchingStrategy::All);
     s.query("quick brown");
     let SearchResult { documents_ids, .. } = s.execute().unwrap();
-    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[10, 11, 12, 13, 3, 4, 2, 1, 0, 6, 8, 7, 9, 5]");
+    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[10, 11, 12, 13, 2, 3, 4, 1, 0, 6, 8, 7, 9, 5]");
 }
 
 #[test]
@@ -176,5 +176,5 @@ fn test_attribute_position_ngrams() {
     s.terms_matching_strategy(TermsMatchingStrategy::All);
     s.query("quick brown");
     let SearchResult { documents_ids, .. } = s.execute().unwrap();
-    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[10, 11, 12, 13, 3, 4, 2, 1, 0, 6, 8, 7, 9, 5]");
+    insta::assert_snapshot!(format!("{documents_ids:?}"), @"[10, 11, 12, 13, 2, 3, 4, 1, 0, 6, 8, 7, 9, 5]");
 }

milli/src/search/new/tests/distinct.rs

@@ -527,7 +527,7 @@ fn test_distinct_all_candidates() {
     let SearchResult { documents_ids, candidates, .. } = s.execute().unwrap();
     let candidates = candidates.iter().collect::<Vec<_>>();
     insta::assert_snapshot!(format!("{documents_ids:?}"), @"[14, 26, 4, 7, 17, 23, 1, 19, 25, 8, 20, 24]");
-    // TODO: this is incorrect!
+    // This is incorrect, but unfortunately impossible to do better efficiently.
     insta::assert_snapshot!(format!("{candidates:?}"), @"[1, 4, 7, 8, 14, 17, 19, 20, 23, 24, 25, 26]");
 }
 

milli/src/search/new/tests/proximity.rs

@@ -125,8 +125,8 @@ fn create_edge_cases_index() -> TempIndex {
         // The next 5 documents lay out a trap with the split word, phrase search, or synonym `sun flower`.
         // If the search query is "sunflower", the split word "Sun Flower" will match some documents.
         // If the query is `sunflower wilting`, then we should make sure that
-        // the sprximity condition `flower wilting: sprx N` also comes with the condition
+        // the proximity condition `flower wilting: sprx N` also comes with the condition
-        // `sun wilting: sprx N+1`. TODO: this is not the exact condition we use for now. 
+        // `sun wilting: sprx N+1`, but this is not the exact condition we use for now.
         // We only check that the phrase `sun flower` exists and `flower wilting: sprx N`, which
         // is better than nothing but not the best.
         {
@@ -299,7 +299,7 @@ fn test_proximity_split_word() {
     let SearchResult { documents_ids, .. } = s.execute().unwrap();
     insta::assert_snapshot!(format!("{documents_ids:?}"), @"[2, 4, 5, 1, 3]");
     let texts = collect_field_values(&index, &txn, "text", &documents_ids);
-    // TODO: "2" and "4" should be swapped ideally
+    // "2" and "4" should be swapped ideally
     insta::assert_debug_snapshot!(texts, @r###"
     [
         "\"Sun Flower sounds like the title of a painting, maybe about a flower wilting under the heat.\"",
@@ -316,7 +316,7 @@ fn test_proximity_split_word() {
     let SearchResult { documents_ids, .. } = s.execute().unwrap();
     insta::assert_snapshot!(format!("{documents_ids:?}"), @"[2, 4, 1]");
     let texts = collect_field_values(&index, &txn, "text", &documents_ids);
-    // TODO: "2" and "4" should be swapped ideally
+    // "2" and "4" should be swapped ideally
     insta::assert_debug_snapshot!(texts, @r###"
     [
         "\"Sun Flower sounds like the title of a painting, maybe about a flower wilting under the heat.\"",
@@ -341,7 +341,7 @@ fn test_proximity_split_word() {
     let SearchResult { documents_ids, .. } = s.execute().unwrap();
     insta::assert_snapshot!(format!("{documents_ids:?}"), @"[2, 4, 1]");
     let texts = collect_field_values(&index, &txn, "text", &documents_ids);
-    // TODO: "2" and "4" should be swapped ideally
+    // "2" and "4" should be swapped ideally
     insta::assert_debug_snapshot!(texts, @r###"
     [
         "\"Sun Flower sounds like the title of a painting, maybe about a flower wilting under the heat.\"",

milli/src/search/new/tests/proximity_typo.rs

@@ -2,9 +2,8 @@
 This module tests the interactions between the proximity and typo ranking rules.
 
 The proximity ranking rule should transform the query graph such that it
-only contains the word pairs that it used to compute its bucket.
+only contains the word pairs that it used to compute its bucket, but this is not currently
-
+implemented.
-TODO: This is not currently implemented.
 */
 
 use crate::index::tests::TempIndex;
@@ -64,7 +63,7 @@ fn test_trap_basic() {
     let SearchResult { documents_ids, .. } = s.execute().unwrap();
     insta::assert_snapshot!(format!("{documents_ids:?}"), @"[0, 1]");
     let texts = collect_field_values(&index, &txn, "text", &documents_ids);
-    // TODO: this is incorrect, 1 should come before 0
+    // This is incorrect, 1 should come before 0
     insta::assert_debug_snapshot!(texts, @r###"
     [
         "\"summer. holiday. sommer holidty\"",

milli/src/search/new/tests/typo.rs

@@ -571,8 +571,8 @@ fn test_typo_synonyms() {
     s.terms_matching_strategy(TermsMatchingStrategy::All);
     s.query("the fast brownish fox jumps over the lackadaisical dog");
 
-    // TODO: is this correct? interaction of ngrams + synonyms means that the
+    // The interaction of ngrams + synonyms means that the multi-word synonyms end up having a typo cost.
-    // multi-word synonyms end up having a typo cost. This is probably not what we want.
+    // This is probably not what we want.
     let SearchResult { documents_ids, .. } = s.execute().unwrap();
     insta::assert_snapshot!(format!("{documents_ids:?}"), @"[21, 0, 22]");
     let texts = collect_field_values(&index, &txn, "text", &documents_ids);

milli/src/search/new/words.rs

@@ -1,87 +0,0 @@
-use roaring::RoaringBitmap;
-
-use super::logger::SearchLogger;
-use super::query_graph::QueryNode;
-use super::resolve_query_graph::compute_query_graph_docids;
-use super::small_bitmap::SmallBitmap;
-use super::{QueryGraph, RankingRule, RankingRuleOutput, SearchContext};
-use crate::{Result, TermsMatchingStrategy};
-
-pub struct Words {
-    exhausted: bool, // TODO: remove
-    query_graph: Option<QueryGraph>,
-    nodes_to_remove: Vec<SmallBitmap<QueryNode>>,
-    terms_matching_strategy: TermsMatchingStrategy,
-}
-impl Words {
-    pub fn new(terms_matching_strategy: TermsMatchingStrategy) -> Self {
-        Self {
-            exhausted: true,
-            query_graph: None,
-            nodes_to_remove: vec![],
-            terms_matching_strategy,
-        }
-    }
-}
-
-impl<'ctx> RankingRule<'ctx, QueryGraph> for Words {
-    fn id(&self) -> String {
-        "words".to_owned()
-    }
-    fn start_iteration(
-        &mut self,
-        ctx: &mut SearchContext<'ctx>,
-        _logger: &mut dyn SearchLogger<QueryGraph>,
-        _universe: &RoaringBitmap,
-        parent_query_graph: &QueryGraph,
-    ) -> Result<()> {
-        self.exhausted = false;
-        self.query_graph = Some(parent_query_graph.clone());
-        self.nodes_to_remove = match self.terms_matching_strategy {
-            TermsMatchingStrategy::Last => {
-                let mut ns = parent_query_graph.removal_order_for_terms_matching_strategy_last(ctx);
-                ns.reverse();
-                ns
-            }
-            TermsMatchingStrategy::All => {
-                vec![]
-            }
-        };
-        Ok(())
-    }
-
-    fn next_bucket(
-        &mut self,
-        ctx: &mut SearchContext<'ctx>,
-        logger: &mut dyn SearchLogger<QueryGraph>,
-        universe: &RoaringBitmap,
-    ) -> Result<Option<RankingRuleOutput<QueryGraph>>> {
-        if self.exhausted {
-            return Ok(None);
-        }
-        let Some(query_graph) = &mut self.query_graph else { panic!() };
-        logger.log_internal_state(query_graph);
-
-        let this_bucket = compute_query_graph_docids(ctx, query_graph, universe)?;
-
-        let child_query_graph = query_graph.clone();
-
-        if self.nodes_to_remove.is_empty() {
-            self.exhausted = true;
-        } else {
-            let nodes_to_remove = self.nodes_to_remove.pop().unwrap();
-            query_graph.remove_nodes_keep_edges(&nodes_to_remove.iter().collect::<Vec<_>>());
-        }
-        Ok(Some(RankingRuleOutput { query: child_query_graph, candidates: this_bucket }))
-    }
-
-    fn end_iteration(
-        &mut self,
-        _ctx: &mut SearchContext<'ctx>,
-        _logger: &mut dyn SearchLogger<QueryGraph>,
-    ) {
-        self.exhausted = true;
-        self.nodes_to_remove = vec![];
-        self.query_graph = None;
-    }
-}

milli/src/snapshot_tests.rs

@@ -89,7 +89,6 @@ Create a snapshot test of the given database.
     - `exact_word_docids`
     - `word_prefix_docids`
     - `exact_word_prefix_docids`
-    - `docid_word_positions`
     - `word_pair_proximity_docids`
     - `word_prefix_pair_proximity_docids`
     - `word_position_docids`
@@ -217,11 +216,6 @@ pub fn snap_exact_word_prefix_docids(index: &Index) -> String {
         &format!("{s:<16} {}", display_bitmap(&b))
     })
 }
-pub fn snap_docid_word_positions(index: &Index) -> String {
-    make_db_snap_from_iter!(index, docid_word_positions, |((idx, s), b)| {
-        &format!("{idx:<6} {s:<16} {}", display_bitmap(&b))
-    })
-}
 pub fn snap_word_pair_proximity_docids(index: &Index) -> String {
     make_db_snap_from_iter!(index, word_pair_proximity_docids, |((proximity, word1, word2), b)| {
         &format!("{proximity:<2} {word1:<16} {word2:<16} {}", display_bitmap(&b))
@@ -324,7 +318,7 @@ pub fn snap_field_distributions(index: &Index) -> String {
     let rtxn = index.read_txn().unwrap();
     let mut snap = String::new();
     for (field, count) in index.field_distribution(&rtxn).unwrap() {
-        writeln!(&mut snap, "{field:<16} {count:<6}").unwrap();
+        writeln!(&mut snap, "{field:<16} {count:<6} |").unwrap();
     }
     snap
 }
@@ -334,7 +328,7 @@ pub fn snap_fields_ids_map(index: &Index) -> String {
     let mut snap = String::new();
     for field_id in fields_ids_map.ids() {
         let name = fields_ids_map.name(field_id).unwrap();
-        writeln!(&mut snap, "{field_id:<3} {name:<16}").unwrap();
+        writeln!(&mut snap, "{field_id:<3} {name:<16} |").unwrap();
     }
     snap
 }
@@ -477,9 +471,6 @@ macro_rules! full_snap_of_db {
     ($index:ident, exact_word_prefix_docids) => {{
         $crate::snapshot_tests::snap_exact_word_prefix_docids(&$index)
     }};
-    ($index:ident, docid_word_positions) => {{
-        $crate::snapshot_tests::snap_docid_word_positions(&$index)
-    }};
     ($index:ident, word_pair_proximity_docids) => {{
         $crate::snapshot_tests::snap_word_pair_proximity_docids(&$index)
     }};

milli/src/snapshots/index.rs/initial_field_distribution/1/field_distribution.snap

@@ -1,7 +1,7 @@
 ---
 source: milli/src/index.rs
 ---
-age              1     
+age              1      |
-id               2     
+id               2      |
-name             2     
+name             2      |
 

milli/src/snapshots/index.rs/initial_field_distribution/field_distribution.snap

@@ -1,7 +1,7 @@
 ---
 source: milli/src/index.rs
 ---
-age              1     
+age              1      |
-id               2     
+id               2      |
-name             2     
+name             2      |
 

milli/src/update/clear_documents.rs

@@ -23,7 +23,6 @@ impl<'t, 'u, 'i> ClearDocuments<'t, 'u, 'i> {
             exact_word_docids,
             word_prefix_docids,
             exact_word_prefix_docids,
-            docid_word_positions,
             word_pair_proximity_docids,
             word_prefix_pair_proximity_docids,
             prefix_word_pair_proximity_docids,
@@ -80,7 +79,6 @@ impl<'t, 'u, 'i> ClearDocuments<'t, 'u, 'i> {
         exact_word_docids.clear(self.wtxn)?;
         word_prefix_docids.clear(self.wtxn)?;
         exact_word_prefix_docids.clear(self.wtxn)?;
-        docid_word_positions.clear(self.wtxn)?;
         word_pair_proximity_docids.clear(self.wtxn)?;
         word_prefix_pair_proximity_docids.clear(self.wtxn)?;
         prefix_word_pair_proximity_docids.clear(self.wtxn)?;
@@ -141,7 +139,6 @@ mod tests {
 
         assert!(index.word_docids.is_empty(&rtxn).unwrap());
         assert!(index.word_prefix_docids.is_empty(&rtxn).unwrap());
-        assert!(index.docid_word_positions.is_empty(&rtxn).unwrap());
         assert!(index.word_pair_proximity_docids.is_empty(&rtxn).unwrap());
         assert!(index.field_id_word_count_docids.is_empty(&rtxn).unwrap());
         assert!(index.word_prefix_pair_proximity_docids.is_empty(&rtxn).unwrap());

milli/src/update/delete_documents.rs

@@ -1,5 +1,5 @@
 use std::collections::btree_map::Entry;
-use std::collections::{HashMap, HashSet};
+use std::collections::{BTreeSet, HashMap, HashSet};
 
 use fst::IntoStreamer;
 use heed::types::{ByteSlice, DecodeIgnore, Str, UnalignedSlice};
@@ -15,8 +15,7 @@ use crate::facet::FacetType;
 use crate::heed_codec::facet::FieldDocIdFacetCodec;
 use crate::heed_codec::CboRoaringBitmapCodec;
 use crate::{
-    ExternalDocumentsIds, FieldId, FieldIdMapMissingEntry, Index, Result, RoaringBitmapCodec,
+    ExternalDocumentsIds, FieldId, FieldIdMapMissingEntry, Index, Result, RoaringBitmapCodec, BEU32,
-    SmallString32, BEU32,
 };
 
 pub struct DeleteDocuments<'t, 'u, 'i> {
@@ -72,7 +71,6 @@ impl std::fmt::Display for DeletionStrategy {
 pub(crate) struct DetailedDocumentDeletionResult {
     pub deleted_documents: u64,
     pub remaining_documents: u64,
-    pub soft_deletion_used: bool,
 }
 
 impl<'t, 'u, 'i> DeleteDocuments<'t, 'u, 'i> {
@@ -109,11 +107,8 @@ impl<'t, 'u, 'i> DeleteDocuments<'t, 'u, 'i> {
         Some(docid)
     }
     pub fn execute(self) -> Result<DocumentDeletionResult> {
-        let DetailedDocumentDeletionResult {
+        let DetailedDocumentDeletionResult { deleted_documents, remaining_documents } =
-            deleted_documents,
+            self.execute_inner()?;
-            remaining_documents,
-            soft_deletion_used: _,
-        } = self.execute_inner()?;
 
         Ok(DocumentDeletionResult { deleted_documents, remaining_documents })
     }
@@ -134,7 +129,6 @@ impl<'t, 'u, 'i> DeleteDocuments<'t, 'u, 'i> {
             return Ok(DetailedDocumentDeletionResult {
                 deleted_documents: 0,
                 remaining_documents: 0,
-                soft_deletion_used: false,
             });
         }
 
@@ -150,7 +144,6 @@ impl<'t, 'u, 'i> DeleteDocuments<'t, 'u, 'i> {
             return Ok(DetailedDocumentDeletionResult {
                 deleted_documents: current_documents_ids_len,
                 remaining_documents,
-                soft_deletion_used: false,
             });
         }
 
@@ -219,7 +212,6 @@ impl<'t, 'u, 'i> DeleteDocuments<'t, 'u, 'i> {
             return Ok(DetailedDocumentDeletionResult {
                 deleted_documents: self.to_delete_docids.len(),
                 remaining_documents: documents_ids.len(),
-                soft_deletion_used: true,
             });
         }
 
@@ -232,7 +224,6 @@ impl<'t, 'u, 'i> DeleteDocuments<'t, 'u, 'i> {
             exact_word_docids,
             word_prefix_docids,
             exact_word_prefix_docids,
-            docid_word_positions,
             word_pair_proximity_docids,
             field_id_word_count_docids,
             word_prefix_pair_proximity_docids,
@@ -251,23 +242,9 @@ impl<'t, 'u, 'i> DeleteDocuments<'t, 'u, 'i> {
             facet_id_is_empty_docids,
             documents,
         } = self.index;
-
+        // Remove from the documents database
-        // Retrieve the words contained in the documents.
-        let mut words = Vec::new();
         for docid in &self.to_delete_docids {
             documents.delete(self.wtxn, &BEU32::new(docid))?;
-
-            // We iterate through the words positions of the document id, retrieve the word and delete the positions.
-            // We create an iterator to be able to get the content and delete the key-value itself.
-            // It's faster to acquire a cursor to get and delete, as we avoid traversing the LMDB B-Tree two times but only once.
-            let mut iter = docid_word_positions.prefix_iter_mut(self.wtxn, &(docid, ""))?;
-            while let Some(result) = iter.next() {
-                let ((_docid, word), _positions) = result?;
-                // This boolean will indicate if we must remove this word from the words FST.
-                words.push((SmallString32::from(word), false));
-                // safety: we don't keep references from inside the LMDB database.
-                unsafe { iter.del_current()? };
-            }
         }
         // We acquire the current external documents ids map...
         // Note that its soft-deleted document ids field will be equal to the `to_delete_docids`
@@ -278,42 +255,27 @@ impl<'t, 'u, 'i> DeleteDocuments<'t, 'u, 'i> {
         let new_external_documents_ids = new_external_documents_ids.into_static();
         self.index.put_external_documents_ids(self.wtxn, &new_external_documents_ids)?;
 
-        // Maybe we can improve the get performance of the words
+        let mut words_to_keep = BTreeSet::default();
-        // if we sort the words first, keeping the LMDB pages in cache.
+        let mut words_to_delete = BTreeSet::default();
-        words.sort_unstable();
-
         // We iterate over the words and delete the documents ids
         // from the word docids database.
-        for (word, must_remove) in &mut words {
         remove_from_word_docids(
             self.wtxn,
             word_docids,
-                word.as_str(),
-                must_remove,
             &self.to_delete_docids,
+            &mut words_to_keep,
+            &mut words_to_delete,
         )?;
-
         remove_from_word_docids(
             self.wtxn,
             exact_word_docids,
-                word.as_str(),
-                must_remove,
             &self.to_delete_docids,
+            &mut words_to_keep,
+            &mut words_to_delete,
         )?;
-        }
 
         // We construct an FST set that contains the words to delete from the words FST.
-        let words_to_delete =
+        let words_to_delete = fst::Set::from_iter(words_to_delete.difference(&words_to_keep))?;
-            words.iter().filter_map(
-                |(word, must_remove)| {
-                    if *must_remove {
-                        Some(word.as_str())
-                    } else {
-                        None
-                    }
-                },
-            );
-        let words_to_delete = fst::Set::from_iter(words_to_delete)?;
 
         let new_words_fst = {
             // We retrieve the current words FST from the database.
@@ -472,7 +434,6 @@ impl<'t, 'u, 'i> DeleteDocuments<'t, 'u, 'i> {
         Ok(DetailedDocumentDeletionResult {
             deleted_documents: self.to_delete_docids.len(),
             remaining_documents: documents_ids.len(),
-            soft_deletion_used: false,
         })
     }
 
@@ -532,23 +493,24 @@ fn remove_from_word_prefix_docids(
 fn remove_from_word_docids(
     txn: &mut heed::RwTxn,
     db: &heed::Database<Str, RoaringBitmapCodec>,
-    word: &str,
-    must_remove: &mut bool,
     to_remove: &RoaringBitmap,
+    words_to_keep: &mut BTreeSet<String>,
+    words_to_remove: &mut BTreeSet<String>,
 ) -> Result<()> {
     // We create an iterator to be able to get the content and delete the word docids.
     // It's faster to acquire a cursor to get and delete or put, as we avoid traversing
     // the LMDB B-Tree two times but only once.
-    let mut iter = db.prefix_iter_mut(txn, word)?;
+    let mut iter = db.iter_mut(txn)?;
-    if let Some((key, mut docids)) = iter.next().transpose()? {
+    while let Some((key, mut docids)) = iter.next().transpose()? {
-        if key == word {
         let previous_len = docids.len();
         docids -= to_remove;
         if docids.is_empty() {
             // safety: we don't keep references from inside the LMDB database.
             unsafe { iter.del_current()? };
-                *must_remove = true;
+            words_to_remove.insert(key.to_owned());
-            } else if docids.len() != previous_len {
+        } else {
+            words_to_keep.insert(key.to_owned());
+            if docids.len() != previous_len {
                 let key = key.to_owned();
                 // safety: we don't keep references from inside the LMDB database.
                 unsafe { iter.put_current(&key, &docids)? };
@@ -627,7 +589,7 @@ mod tests {
 
     use super::*;
     use crate::index::tests::TempIndex;
-    use crate::{db_snap, Filter};
+    use crate::{db_snap, Filter, Search};
 
     fn delete_documents<'t>(
         wtxn: &mut RwTxn<'t, '_>,
@@ -1199,4 +1161,52 @@ mod tests {
             DeletionStrategy::AlwaysSoft,
         );
     }
+
+    #[test]
+    fn delete_words_exact_attributes() {
+        let index = TempIndex::new();
+
+        index
+            .update_settings(|settings| {
+                settings.set_primary_key(S("id"));
+                settings.set_searchable_fields(vec![S("text"), S("exact")]);
+                settings.set_exact_attributes(vec![S("exact")].into_iter().collect());
+            })
+            .unwrap();
+
+        index
+            .add_documents(documents!([
+                { "id": 0, "text": "hello" },
+                { "id": 1, "exact": "hello"}
+            ]))
+            .unwrap();
+        db_snap!(index, word_docids, 1, @r###"
+        hello            [0, ]
+        "###);
+        db_snap!(index, exact_word_docids, 1, @r###"
+        hello            [1, ]
+        "###);
+        db_snap!(index, words_fst, 1, @"300000000000000001084cfcfc2ce1000000016000000090ea47f");
+
+        let mut wtxn = index.write_txn().unwrap();
+        let deleted_internal_ids =
+            delete_documents(&mut wtxn, &index, &["1"], DeletionStrategy::AlwaysHard);
+        wtxn.commit().unwrap();
+
+        db_snap!(index, word_docids, 2, @r###"
+        hello            [0, ]
+        "###);
+        db_snap!(index, exact_word_docids, 2, @"");
+        db_snap!(index, words_fst, 2, @"300000000000000001084cfcfc2ce1000000016000000090ea47f");
+
+        insta::assert_snapshot!(format!("{deleted_internal_ids:?}"), @"[1]");
+        let txn = index.read_txn().unwrap();
+        let words = index.words_fst(&txn).unwrap().into_stream().into_strs().unwrap();
+        insta::assert_snapshot!(format!("{words:?}"), @r###"["hello"]"###);
+
+        let mut s = Search::new(&txn, &index);
+        s.query("hello");
+        let crate::SearchResult { documents_ids, .. } = s.execute().unwrap();
+        insta::assert_snapshot!(format!("{documents_ids:?}"), @"[0]");
+    }
 }

milli/src/update/facet/mod.rs

@@ -261,7 +261,9 @@ pub(crate) mod test_helpers {
             let options = options.map_size(4096 * 4 * 1000 * 100);
             let tempdir = tempfile::TempDir::new().unwrap();
             let env = options.open(tempdir.path()).unwrap();
-            let content = env.create_database(None).unwrap();
+            let mut wtxn = env.write_txn().unwrap();
+            let content = env.create_database(&mut wtxn, None).unwrap();
+            wtxn.commit().unwrap();
 
             FacetIndex {
                 content,