Merge #5000

5000: Implement the experimental drop search after and nb search per core r=Kerollmops a=irevoire

# Pull Request

## Related issue
Fixes https://github.com/meilisearch/meilisearch/issues/4997
Fixes https://github.com/meilisearch/meilisearch/issues/4995

## What does this PR do?
- Add an experimental parameter to decide how many searches can be processed per core
- Add an experimental parameter to configure after how many seconds a search should be dropped

Co-authored-by: Tamo <tamo@meilisearch.com>

meilisearch/src/analytics/segment_analytics.rs

@@ -265,6 +265,8 @@ struct Infos {
     experimental_contains_filter: bool,
     experimental_enable_metrics: bool,
     experimental_search_queue_size: usize,
+    experimental_drop_search_after: usize,
+    experimental_nb_searches_per_core: usize,
     experimental_logs_mode: LogMode,
     experimental_replication_parameters: bool,
     experimental_enable_logs_route: bool,
@@ -308,6 +310,8 @@ impl From<Opt> for Infos {
             experimental_contains_filter,
             experimental_enable_metrics,
             experimental_search_queue_size,
+            experimental_drop_search_after,
+            experimental_nb_searches_per_core,
             experimental_logs_mode,
             experimental_replication_parameters,
             experimental_enable_logs_route,
@@ -359,6 +363,8 @@ impl From<Opt> for Infos {
             experimental_contains_filter,
             experimental_enable_metrics,
             experimental_search_queue_size,
+            experimental_drop_search_after: experimental_drop_search_after.into(),
+            experimental_nb_searches_per_core: experimental_nb_searches_per_core.into(),
             experimental_logs_mode,
             experimental_replication_parameters,
             experimental_enable_logs_route,

meilisearch/src/main.rs

@@ -5,6 +5,7 @@ use std::path::PathBuf;
 use std::str::FromStr;
 use std::sync::Arc;
 use std::thread::available_parallelism;
+use std::time::Duration;
 
 use actix_web::http::KeepAlive;
 use actix_web::web::Data;
@@ -153,8 +154,14 @@ async fn run_http(
     let auth_controller = Data::from(auth_controller);
     let search_queue = SearchQueue::new(
         opt.experimental_search_queue_size,
-        available_parallelism().unwrap_or(NonZeroUsize::new(2).unwrap()),
+        available_parallelism()
-    );
+            .unwrap_or(NonZeroUsize::new(2).unwrap())
+            .checked_mul(opt.experimental_nb_searches_per_core)
+            .unwrap_or(NonZeroUsize::MAX),
+    )
+    .with_time_to_abort(Duration::from_secs(
+        usize::from(opt.experimental_drop_search_after) as u64
+    ));
     let search_queue = Data::new(search_queue);
 
     let http_server = HttpServer::new(move || {

meilisearch/src/option.rs

@@ -2,7 +2,7 @@ use std::env::VarError;
 use std::ffi::OsStr;
 use std::fmt::Display;
 use std::io::{BufReader, Read};
-use std::num::ParseIntError;
+use std::num::{NonZeroUsize, ParseIntError};
 use std::ops::Deref;
 use std::path::PathBuf;
 use std::str::FromStr;
@@ -55,6 +55,8 @@ const MEILI_EXPERIMENTAL_ENABLE_LOGS_ROUTE: &str = "MEILI_EXPERIMENTAL_ENABLE_LO
 const MEILI_EXPERIMENTAL_CONTAINS_FILTER: &str = "MEILI_EXPERIMENTAL_CONTAINS_FILTER";
 const MEILI_EXPERIMENTAL_ENABLE_METRICS: &str = "MEILI_EXPERIMENTAL_ENABLE_METRICS";
 const MEILI_EXPERIMENTAL_SEARCH_QUEUE_SIZE: &str = "MEILI_EXPERIMENTAL_SEARCH_QUEUE_SIZE";
+const MEILI_EXPERIMENTAL_DROP_SEARCH_AFTER: &str = "MEILI_EXPERIMENTAL_DROP_SEARCH_AFTER";
+const MEILI_EXPERIMENTAL_NB_SEARCHES_PER_CORE: &str = "MEILI_EXPERIMENTAL_NB_SEARCHES_PER_CORE";
 const MEILI_EXPERIMENTAL_REDUCE_INDEXING_MEMORY_USAGE: &str =
     "MEILI_EXPERIMENTAL_REDUCE_INDEXING_MEMORY_USAGE";
 const MEILI_EXPERIMENTAL_MAX_NUMBER_OF_BATCHED_TASKS: &str =
@@ -361,6 +363,22 @@ pub struct Opt {
     #[serde(default)]
     pub experimental_search_queue_size: usize,
 
+    /// Experimental drop search after. For more information, see: <https://github.com/orgs/meilisearch/discussions/783>
+    ///
+    /// Let you customize after how many seconds Meilisearch should consider a search request irrelevant and drop it.
+    /// The default value is 60.
+    #[clap(long, env = MEILI_EXPERIMENTAL_DROP_SEARCH_AFTER, default_value_t = default_drop_search_after())]
+    #[serde(default = "default_drop_search_after")]
+    pub experimental_drop_search_after: NonZeroUsize,
+
+    /// Experimental number of searches per core. For more information, see: <https://github.com/orgs/meilisearch/discussions/784>
+    ///
+    /// Lets you customize how many search requests can run on each core concurrently.
+    /// The default value is 4.
+    #[clap(long, env = MEILI_EXPERIMENTAL_NB_SEARCHES_PER_CORE, default_value_t = default_nb_searches_per_core())]
+    #[serde(default = "default_nb_searches_per_core")]
+    pub experimental_nb_searches_per_core: NonZeroUsize,
+
     /// Experimental logs mode feature. For more information, see: <https://github.com/orgs/meilisearch/discussions/723>
     ///
     /// Change the mode of the logs on the console.
@@ -492,6 +510,8 @@ impl Opt {
             experimental_contains_filter,
             experimental_enable_metrics,
             experimental_search_queue_size,
+            experimental_drop_search_after,
+            experimental_nb_searches_per_core,
             experimental_logs_mode,
             experimental_enable_logs_route,
             experimental_replication_parameters,
@@ -559,6 +579,14 @@ impl Opt {
             MEILI_EXPERIMENTAL_SEARCH_QUEUE_SIZE,
             experimental_search_queue_size.to_string(),
         );
+        export_to_env_if_not_present(
+            MEILI_EXPERIMENTAL_DROP_SEARCH_AFTER,
+            experimental_drop_search_after.to_string(),
+        );
+        export_to_env_if_not_present(
+            MEILI_EXPERIMENTAL_NB_SEARCHES_PER_CORE,
+            experimental_nb_searches_per_core.to_string(),
+        );
         export_to_env_if_not_present(
             MEILI_EXPERIMENTAL_LOGS_MODE,
             experimental_logs_mode.to_string(),
@@ -890,6 +918,14 @@ fn default_dump_dir() -> PathBuf {
     PathBuf::from(DEFAULT_DUMP_DIR)
 }
 
+fn default_drop_search_after() -> NonZeroUsize {
+    NonZeroUsize::new(60).unwrap()
+}
+
+fn default_nb_searches_per_core() -> NonZeroUsize {
+    NonZeroUsize::new(4).unwrap()
+}
+
 /// Indicates if a snapshot was scheduled, and if yes with which interval.
 #[derive(Debug, Default, Copy, Clone, Deserialize, Serialize)]
 pub enum ScheduleSnapshot {