meilisearch/milli/src/search/facet/facet_distribution.rs
2023-03-23 09:39:16 +01:00

812 lines
28 KiB
Rust

use std::collections::{BTreeMap, HashSet};
use std::ops::ControlFlow;
use std::{fmt, mem};
use heed::types::ByteSlice;
use heed::BytesDecode;
use roaring::RoaringBitmap;
use crate::error::UserError;
use crate::facet::FacetType;
use crate::heed_codec::facet::{
FacetGroupKeyCodec, FacetGroupValueCodec, FieldDocIdFacetF64Codec, FieldDocIdFacetStringCodec,
OrderedF64Codec,
};
use crate::heed_codec::{ByteSliceRefCodec, StrRefCodec};
use crate::search::facet::facet_distribution_iter;
use crate::{FieldId, Index, Result};
/// The default number of values by facets that will
/// be fetched from the key-value store.
pub const DEFAULT_VALUES_PER_FACET: usize = 100;
/// Threshold on the number of candidates that will make
/// the system to choose between one algorithm or another.
const CANDIDATES_THRESHOLD: u64 = 3000;
pub struct FacetDistribution<'a> {
facets: Option<HashSet<String>>,
candidates: Option<RoaringBitmap>,
max_values_per_facet: usize,
rtxn: &'a heed::RoTxn<'a>,
index: &'a Index,
}
impl<'a> FacetDistribution<'a> {
pub fn new(rtxn: &'a heed::RoTxn, index: &'a Index) -> FacetDistribution<'a> {
FacetDistribution {
facets: None,
candidates: None,
max_values_per_facet: DEFAULT_VALUES_PER_FACET,
rtxn,
index,
}
}
pub fn facets<I: IntoIterator<Item = A>, A: AsRef<str>>(&mut self, names: I) -> &mut Self {
self.facets = Some(names.into_iter().map(|s| s.as_ref().to_string()).collect());
self
}
pub fn max_values_per_facet(&mut self, max: usize) -> &mut Self {
self.max_values_per_facet = max;
self
}
pub fn candidates(&mut self, candidates: RoaringBitmap) -> &mut Self {
self.candidates = Some(candidates);
self
}
/// There is a small amount of candidates OR we ask for facet string values so we
/// decide to iterate over the facet values of each one of them, one by one.
fn facet_distribution_from_documents(
&self,
field_id: FieldId,
facet_type: FacetType,
candidates: &RoaringBitmap,
distribution: &mut BTreeMap<String, u64>,
) -> heed::Result<()> {
match facet_type {
FacetType::Number => {
let mut key_buffer: Vec<_> = field_id.to_be_bytes().to_vec();
let distribution_prelength = distribution.len();
let db = self.index.field_id_docid_facet_f64s;
for docid in candidates {
key_buffer.truncate(mem::size_of::<FieldId>());
key_buffer.extend_from_slice(&docid.to_be_bytes());
let iter = db
.remap_key_type::<ByteSlice>()
.prefix_iter(self.rtxn, &key_buffer)?
.remap_key_type::<FieldDocIdFacetF64Codec>();
for result in iter {
let ((_, _, value), ()) = result?;
*distribution.entry(value.to_string()).or_insert(0) += 1;
if distribution.len() - distribution_prelength == self.max_values_per_facet
{
break;
}
}
}
}
FacetType::String => {
let mut normalized_distribution = BTreeMap::new();
let mut key_buffer: Vec<_> = field_id.to_be_bytes().to_vec();
let db = self.index.field_id_docid_facet_strings;
'outer: for docid in candidates {
key_buffer.truncate(mem::size_of::<FieldId>());
key_buffer.extend_from_slice(&docid.to_be_bytes());
let iter = db
.remap_key_type::<ByteSlice>()
.prefix_iter(self.rtxn, &key_buffer)?
.remap_key_type::<FieldDocIdFacetStringCodec>();
for result in iter {
let ((_, _, normalized_value), original_value) = result?;
let (_, count) = normalized_distribution
.entry(normalized_value)
.or_insert_with(|| (original_value, 0));
*count += 1;
if normalized_distribution.len() == self.max_values_per_facet {
break 'outer;
}
}
}
let iter = normalized_distribution
.into_iter()
.map(|(_normalized, (original, count))| (original.to_string(), count));
distribution.extend(iter);
}
}
Ok(())
}
/// There is too much documents, we use the facet levels to move throught
/// the facet values, to find the candidates and values associated.
fn facet_numbers_distribution_from_facet_levels(
&self,
field_id: FieldId,
candidates: &RoaringBitmap,
distribution: &mut BTreeMap<String, u64>,
) -> heed::Result<()> {
facet_distribution_iter::iterate_over_facet_distribution(
self.rtxn,
self.index
.facet_id_f64_docids
.remap_key_type::<FacetGroupKeyCodec<ByteSliceRefCodec>>(),
field_id,
candidates,
|facet_key, nbr_docids, _| {
let facet_key = OrderedF64Codec::bytes_decode(facet_key).unwrap();
distribution.insert(facet_key.to_string(), nbr_docids);
if distribution.len() == self.max_values_per_facet {
Ok(ControlFlow::Break(()))
} else {
Ok(ControlFlow::Continue(()))
}
},
)
}
fn facet_strings_distribution_from_facet_levels(
&self,
field_id: FieldId,
candidates: &RoaringBitmap,
distribution: &mut BTreeMap<String, u64>,
) -> heed::Result<()> {
facet_distribution_iter::iterate_over_facet_distribution(
self.rtxn,
self.index
.facet_id_string_docids
.remap_key_type::<FacetGroupKeyCodec<ByteSliceRefCodec>>(),
field_id,
candidates,
|facet_key, nbr_docids, any_docid| {
let facet_key = StrRefCodec::bytes_decode(facet_key).unwrap();
let key: (FieldId, _, &str) = (field_id, any_docid, facet_key);
let original_string = self
.index
.field_id_docid_facet_strings
.get(self.rtxn, &key)?
.unwrap()
.to_owned();
distribution.insert(original_string, nbr_docids);
if distribution.len() == self.max_values_per_facet {
Ok(ControlFlow::Break(()))
} else {
Ok(ControlFlow::Continue(()))
}
},
)
}
/// Placeholder search, a.k.a. no candidates were specified. We iterate throught the
/// facet values one by one and iterate on the facet level 0 for numbers.
fn facet_values_from_raw_facet_database(
&self,
field_id: FieldId,
) -> heed::Result<BTreeMap<String, u64>> {
let mut distribution = BTreeMap::new();
let db = self.index.facet_id_f64_docids;
let mut prefix = vec![];
prefix.extend_from_slice(&field_id.to_be_bytes());
prefix.push(0); // read values from level 0 only
let iter = db
.as_polymorph()
.prefix_iter::<_, ByteSlice, ByteSlice>(self.rtxn, prefix.as_slice())?
.remap_types::<FacetGroupKeyCodec<OrderedF64Codec>, FacetGroupValueCodec>();
for result in iter {
let (key, value) = result?;
distribution.insert(key.left_bound.to_string(), value.bitmap.len());
if distribution.len() == self.max_values_per_facet {
break;
}
}
let iter = self
.index
.facet_id_string_docids
.as_polymorph()
.prefix_iter::<_, ByteSlice, ByteSlice>(self.rtxn, prefix.as_slice())?
.remap_types::<FacetGroupKeyCodec<StrRefCodec>, FacetGroupValueCodec>();
for result in iter {
let (key, value) = result?;
let docid = value.bitmap.iter().next().unwrap();
let key: (FieldId, _, &'a str) = (field_id, docid, key.left_bound);
let original_string =
self.index.field_id_docid_facet_strings.get(self.rtxn, &key)?.unwrap().to_owned();
distribution.insert(original_string, value.bitmap.len());
if distribution.len() == self.max_values_per_facet {
break;
}
}
Ok(distribution)
}
fn facet_values(&self, field_id: FieldId) -> heed::Result<BTreeMap<String, u64>> {
use FacetType::{Number, String};
match self.candidates {
Some(ref candidates) => {
// Classic search, candidates were specified, we must return facet values only related
// to those candidates. We also enter here for facet strings for performance reasons.
let mut distribution = BTreeMap::new();
if candidates.len() <= CANDIDATES_THRESHOLD {
self.facet_distribution_from_documents(
field_id,
Number,
candidates,
&mut distribution,
)?;
self.facet_distribution_from_documents(
field_id,
String,
candidates,
&mut distribution,
)?;
} else {
self.facet_numbers_distribution_from_facet_levels(
field_id,
candidates,
&mut distribution,
)?;
self.facet_strings_distribution_from_facet_levels(
field_id,
candidates,
&mut distribution,
)?;
}
Ok(distribution)
}
None => self.facet_values_from_raw_facet_database(field_id),
}
}
pub fn compute_stats(&self) -> Result<BTreeMap<String, (f64, f64)>> {
let fields_ids_map = self.index.fields_ids_map(self.rtxn)?;
let filterable_fields = self.index.filterable_fields(self.rtxn)?;
let candidates = if let Some(candidates) = self.candidates.clone() {
candidates
} else {
return Ok(Default::default());
};
let fields = match &self.facets {
Some(facets) => {
let invalid_fields: HashSet<_> = facets
.iter()
.filter(|facet| !crate::is_faceted(facet, &filterable_fields))
.collect();
if !invalid_fields.is_empty() {
return Err(UserError::InvalidFacetsDistribution {
invalid_facets_name: invalid_fields.into_iter().cloned().collect(),
valid_facets_name: filterable_fields.into_iter().collect(),
}
.into());
} else {
facets.clone()
}
}
None => filterable_fields,
};
let mut distribution = BTreeMap::new();
for (fid, name) in fields_ids_map.iter() {
if crate::is_faceted(name, &fields) {
let min_value = if let Some(min_value) = crate::search::facet::facet_min_value(
self.index,
self.rtxn,
fid,
candidates.clone(),
)? {
min_value
} else {
continue;
};
let max_value = if let Some(max_value) = crate::search::facet::facet_max_value(
self.index,
self.rtxn,
fid,
candidates.clone(),
)? {
max_value
} else {
continue;
};
distribution.insert(name.to_string(), (min_value, max_value));
}
}
Ok(distribution)
}
pub fn execute(&self) -> Result<BTreeMap<String, BTreeMap<String, u64>>> {
let fields_ids_map = self.index.fields_ids_map(self.rtxn)?;
let filterable_fields = self.index.filterable_fields(self.rtxn)?;
let fields = match self.facets {
Some(ref facets) => {
let invalid_fields: HashSet<_> = facets
.iter()
.filter(|facet| !crate::is_faceted(facet, &filterable_fields))
.collect();
if !invalid_fields.is_empty() {
return Err(UserError::InvalidFacetsDistribution {
invalid_facets_name: invalid_fields.into_iter().cloned().collect(),
valid_facets_name: filterable_fields.into_iter().collect(),
}
.into());
} else {
facets.clone()
}
}
None => filterable_fields,
};
let mut distribution = BTreeMap::new();
for (fid, name) in fields_ids_map.iter() {
if crate::is_faceted(name, &fields) {
let values = self.facet_values(fid)?;
distribution.insert(name.to_string(), values);
}
}
Ok(distribution)
}
}
impl fmt::Debug for FacetDistribution<'_> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let FacetDistribution { facets, candidates, max_values_per_facet, rtxn: _, index: _ } =
self;
f.debug_struct("FacetDistribution")
.field("facets", facets)
.field("candidates", candidates)
.field("max_values_per_facet", max_values_per_facet)
.finish()
}
}
#[cfg(test)]
mod tests {
use big_s::S;
use maplit::hashset;
use crate::documents::documents_batch_reader_from_objects;
use crate::index::tests::TempIndex;
use crate::{milli_snap, FacetDistribution};
#[test]
fn few_candidates_few_facet_values() {
// All the tests here avoid using the code in `facet_distribution_iter` because there aren't
// enough candidates.
let mut index = TempIndex::new();
index.index_documents_config.autogenerate_docids = true;
index
.update_settings(|settings| settings.set_filterable_fields(hashset! { S("colour") }))
.unwrap();
let documents = documents!([
{ "colour": "Blue" },
{ "colour": " blue" },
{ "colour": "RED" }
]);
index.add_documents(documents).unwrap();
let txn = index.read_txn().unwrap();
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), @r###"{"colour": {"Blue": 2, "RED": 1}}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates([0, 1, 2].iter().copied().collect())
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), @r###"{"colour": {"Blue": 2, "RED": 1}}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates([1, 2].iter().copied().collect())
.execute()
.unwrap();
// I think it would be fine if " blue" was "Blue" instead.
// We just need to get any non-normalised string I think, even if it's not in
// the candidates
milli_snap!(format!("{map:?}"), @r###"{"colour": {" blue": 1, "RED": 1}}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates([2].iter().copied().collect())
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), @r###"{"colour": {"RED": 1}}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates([0, 1, 2].iter().copied().collect())
.max_values_per_facet(1)
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), @r###"{"colour": {"Blue": 1}}"###);
}
#[test]
fn many_candidates_few_facet_values() {
let mut index = TempIndex::new_with_map_size(4096 * 10_000);
index.index_documents_config.autogenerate_docids = true;
index
.update_settings(|settings| settings.set_filterable_fields(hashset! { S("colour") }))
.unwrap();
let facet_values = ["Red", "RED", " red ", "Blue", "BLUE"];
let mut documents = vec![];
for i in 0..10_000 {
let document = serde_json::json!({
"colour": facet_values[i % 5],
})
.as_object()
.unwrap()
.clone();
documents.push(document);
}
let documents = documents_batch_reader_from_objects(documents);
index.add_documents(documents).unwrap();
let txn = index.read_txn().unwrap();
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), @r###"{"colour": {"Blue": 4000, "Red": 6000}}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.max_values_per_facet(1)
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), @r###"{"colour": {"Blue": 4000}}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((0..10_000).collect())
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), @r###"{"colour": {"Blue": 4000, "Red": 6000}}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((0..5_000).collect())
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), @r###"{"colour": {"Blue": 2000, "Red": 3000}}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((0..5_000).collect())
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), @r###"{"colour": {"Blue": 2000, "Red": 3000}}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((0..5_000).collect())
.max_values_per_facet(1)
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), @r###"{"colour": {"Blue": 2000}}"###);
}
#[test]
fn many_candidates_many_facet_values() {
let mut index = TempIndex::new_with_map_size(4096 * 10_000);
index.index_documents_config.autogenerate_docids = true;
index
.update_settings(|settings| settings.set_filterable_fields(hashset! { S("colour") }))
.unwrap();
let facet_values = (0..1000).map(|x| format!("{x:x}")).collect::<Vec<_>>();
let mut documents = vec![];
for i in 0..10_000 {
let document = serde_json::json!({
"colour": facet_values[i % 1000],
})
.as_object()
.unwrap()
.clone();
documents.push(document);
}
let documents = documents_batch_reader_from_objects(documents);
index.add_documents(documents).unwrap();
let txn = index.read_txn().unwrap();
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), "no_candidates", @"ac9229ed5964d893af96a7076e2f8af5");
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.max_values_per_facet(2)
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), "no_candidates_with_max_2", @r###"{"colour": {"0": 10, "1": 10}}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((0..10_000).collect())
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), "candidates_0_10_000", @"ac9229ed5964d893af96a7076e2f8af5");
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((0..5_000).collect())
.execute()
.unwrap();
milli_snap!(format!("{map:?}"), "candidates_0_5_000", @"825f23a4090d05756f46176987b7d992");
}
#[test]
fn facet_stats() {
let mut index = TempIndex::new_with_map_size(4096 * 10_000);
index.index_documents_config.autogenerate_docids = true;
index
.update_settings(|settings| settings.set_filterable_fields(hashset! { S("colour") }))
.unwrap();
let facet_values = (0..1000).collect::<Vec<_>>();
let mut documents = vec![];
for i in 0..1000 {
let document = serde_json::json!({
"colour": facet_values[i % 1000],
})
.as_object()
.unwrap()
.clone();
documents.push(document);
}
let documents = documents_batch_reader_from_objects(documents);
index.add_documents(documents).unwrap();
let txn = index.read_txn().unwrap();
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "no_candidates", @"{}");
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((0..1000).collect())
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "candidates_0_1000", @r###"{"colour": (0.0, 999.0)}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((217..777).collect())
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "candidates_217_777", @r###"{"colour": (217.0, 776.0)}"###);
}
#[test]
fn facet_stats_array() {
let mut index = TempIndex::new_with_map_size(4096 * 10_000);
index.index_documents_config.autogenerate_docids = true;
index
.update_settings(|settings| settings.set_filterable_fields(hashset! { S("colour") }))
.unwrap();
let facet_values = (0..1000).collect::<Vec<_>>();
let mut documents = vec![];
for i in 0..1000 {
let document = serde_json::json!({
"colour": [facet_values[i % 1000], facet_values[i % 1000] + 1000],
})
.as_object()
.unwrap()
.clone();
documents.push(document);
}
let documents = documents_batch_reader_from_objects(documents);
index.add_documents(documents).unwrap();
let txn = index.read_txn().unwrap();
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "no_candidates", @"{}");
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((0..1000).collect())
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "candidates_0_1000", @r###"{"colour": (0.0, 1999.0)}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((217..777).collect())
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "candidates_217_777", @r###"{"colour": (217.0, 1776.0)}"###);
}
#[test]
fn facet_stats_mixed_array() {
let mut index = TempIndex::new_with_map_size(4096 * 10_000);
index.index_documents_config.autogenerate_docids = true;
index
.update_settings(|settings| settings.set_filterable_fields(hashset! { S("colour") }))
.unwrap();
let facet_values = (0..1000).collect::<Vec<_>>();
let mut documents = vec![];
for i in 0..1000 {
let document = serde_json::json!({
"colour": [facet_values[i % 1000], format!("{}", facet_values[i % 1000] + 1000)],
})
.as_object()
.unwrap()
.clone();
documents.push(document);
}
let documents = documents_batch_reader_from_objects(documents);
index.add_documents(documents).unwrap();
let txn = index.read_txn().unwrap();
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "no_candidates", @"{}");
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((0..1000).collect())
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "candidates_0_1000", @r###"{"colour": (0.0, 999.0)}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((217..777).collect())
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "candidates_217_777", @r###"{"colour": (217.0, 776.0)}"###);
}
#[test]
fn facet_mixed_values() {
let mut index = TempIndex::new_with_map_size(4096 * 10_000);
index.index_documents_config.autogenerate_docids = true;
index
.update_settings(|settings| settings.set_filterable_fields(hashset! { S("colour") }))
.unwrap();
let facet_values = (0..1000).collect::<Vec<_>>();
let mut documents = vec![];
for i in 0..1000 {
let document = if i % 2 == 0 {
serde_json::json!({
"colour": [facet_values[i % 1000], facet_values[i % 1000] + 1000],
})
} else {
serde_json::json!({
"colour": format!("{}", facet_values[i % 1000] + 10000),
})
};
let document = document.as_object().unwrap().clone();
documents.push(document);
}
let documents = documents_batch_reader_from_objects(documents);
index.add_documents(documents).unwrap();
let txn = index.read_txn().unwrap();
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "no_candidates", @"{}");
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((0..1000).collect())
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "candidates_0_1000", @r###"{"colour": (0.0, 1998.0)}"###);
let map = FacetDistribution::new(&txn, &index)
.facets(std::iter::once("colour"))
.candidates((217..777).collect())
.compute_stats()
.unwrap();
milli_snap!(format!("{map:?}"), "candidates_217_777", @r###"{"colour": (218.0, 1776.0)}"###);
}
}