integrate thread_pool

Cargo.lock

@@ -519,6 +519,7 @@ dependencies = [
  "rand_chacha",
  "reqwest",
  "roaring",
+ "scoped_thread_pool",
  "serde_json",
  "tempfile",
 ]
@@ -2062,6 +2063,7 @@ dependencies = [
  "either",
  "fastrand",
  "milli",
+ "scoped_thread_pool",
  "serde",
  "serde_json",
  "tempfile",
@@ -2768,6 +2770,7 @@ dependencies = [
  "page_size",
  "rayon",
  "roaring",
+ "scoped_thread_pool",
  "serde",
  "serde_json",
  "synchronoise",
@@ -3636,6 +3639,7 @@ dependencies = [
  "rustls",
  "rustls-pemfile",
  "rustls-pki-types",
+ "scoped_thread_pool",
  "segment",
  "serde",
  "serde_json",
@@ -3814,6 +3818,7 @@ dependencies = [
  "roaring",
  "rstar",
  "rustc-hash 2.1.0",
+ "scoped_thread_pool",
  "serde",
  "serde_json",
  "slice-group-by",
@@ -5088,6 +5093,13 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "scoped_thread_pool"
+version = "0.1.0"
+dependencies = [
+ "crossbeam-channel",
+]
+
 [[package]]
 name = "scopeguard"
 version = "1.2.0"

crates/benchmarks/Cargo.toml

@@ -17,6 +17,7 @@ csv = "1.3.1"
 memmap2 = "0.9.5"
 milli = { path = "../milli" }
 mimalloc = { version = "0.1.43", default-features = false }
+scoped_thread_pool = { version = "0.1.0", path = "../../../../../../../dev/scoped_thread_pool" }
 serde_json = { version = "1.0.135", features = ["preserve_order"] }
 tempfile = "3.15.0"
 

crates/benchmarks/benches/utils.rs

@@ -2,6 +2,7 @@
 
 use std::fs::{create_dir_all, remove_dir_all, File};
 use std::io::{self, BufReader, BufWriter, Read};
+use std::num::NonZeroUsize;
 use std::path::Path;
 use std::str::FromStr as _;
 
@@ -9,9 +10,11 @@ use anyhow::Context;
 use bumpalo::Bump;
 use criterion::BenchmarkId;
 use memmap2::Mmap;
-use milli::heed::EnvOpenOptions;
+use milli::documents::PrimaryKey;
+use milli::heed::{EnvOpenOptions, RwTxn};
 use milli::progress::Progress;
 use milli::update::new::indexer;
+use milli::update::new::indexer::document_changes::CHUNK_SIZE;
 use milli::update::{IndexDocumentsMethod, IndexerConfig, Settings};
 use milli::vector::EmbeddingConfigs;
 use milli::{Criterion, Filter, Index, Object, TermsMatchingStrategy};
@@ -96,28 +99,59 @@ pub fn base_setup(conf: &Conf) -> Index {
     let mut wtxn = index.write_txn().unwrap();
     let rtxn = index.read_txn().unwrap();
     let db_fields_ids_map = index.fields_ids_map(&rtxn).unwrap();
-    let mut new_fields_ids_map = db_fields_ids_map.clone();
+    let new_fields_ids_map = db_fields_ids_map.clone();
 
     let documents = documents_from(conf.dataset, conf.dataset_format);
     let mut indexer = indexer::DocumentOperation::new(IndexDocumentsMethod::ReplaceDocuments);
     indexer.add_documents(&documents).unwrap();
 
+    index_documents(
+        indexer,
+        &index,
+        &rtxn,
+        new_fields_ids_map,
+        &mut wtxn,
+        config,
+        db_fields_ids_map,
+    );
+
+    wtxn.commit().unwrap();
+    drop(rtxn);
+
+    index
+}
+
+pub fn index_documents(
+    indexer: indexer::DocumentOperation,
+    index: &Index,
+    rtxn: &milli::heed::RoTxn,
+    mut new_fields_ids_map: milli::FieldsIdsMap,
+    wtxn: &mut RwTxn,
+    config: IndexerConfig,
+    db_fields_ids_map: milli::FieldsIdsMap,
+) {
     let indexer_alloc = Bump::new();
+    let thread_count =
+        std::thread::available_parallelism().unwrap_or(NonZeroUsize::new(1).unwrap());
+    let thread_pool = scoped_thread_pool::ThreadPool::new(thread_count, "index".into());
     let (document_changes, _operation_stats, primary_key) = indexer
         .into_changes(
             &indexer_alloc,
-            &index,
+            index,
-            &rtxn,
+            rtxn,
             None,
             &mut new_fields_ids_map,
             &|| false,
             Progress::default(),
+            &thread_pool,
+            CHUNK_SIZE,
         )
         .unwrap();
 
     indexer::index(
-        &mut wtxn,
+        wtxn,
-        &index,
+        index,
+        &thread_pool,
         &milli::ThreadPoolNoAbortBuilder::new().build().unwrap(),
         config.grenad_parameters(),
         &db_fields_ids_map,
@@ -129,11 +163,38 @@ pub fn base_setup(conf: &Conf) -> Index {
         &Progress::default(),
     )
     .unwrap();
+}
 
-    wtxn.commit().unwrap();
+pub fn index_delete_documents(
-    drop(rtxn);
+    indexer: indexer::DocumentDeletion,
-
+    primary_key: PrimaryKey,
-    index
+    wtxn: &mut RwTxn,
+    index: &Index,
+    config: &IndexerConfig,
+    db_fields_ids_map: milli::FieldsIdsMap,
+    new_fields_ids_map: milli::FieldsIdsMap,
+) {
+    let indexer_alloc = Bump::new();
+    let thread_count =
+        std::thread::available_parallelism().unwrap_or(NonZeroUsize::new(1).unwrap());
+    let thread_pool = scoped_thread_pool::ThreadPool::new(thread_count, "index".into());
+    let document_changes =
+        indexer.into_changes(&indexer_alloc, primary_key, &thread_pool, CHUNK_SIZE);
+    indexer::index(
+        wtxn,
+        index,
+        &thread_pool,
+        &milli::ThreadPoolNoAbortBuilder::new().build().unwrap(),
+        config.grenad_parameters(),
+        &db_fields_ids_map,
+        new_fields_ids_map,
+        Some(primary_key),
+        &document_changes,
+        EmbeddingConfigs::default(),
+        &|| false,
+        &Progress::default(),
+    )
+    .unwrap();
 }
 
 pub fn run_benches(c: &mut criterion::Criterion, confs: &[Conf]) {

crates/fuzzers/Cargo.toml

@@ -17,6 +17,7 @@ clap = { version = "4.5.24", features = ["derive"] }
 either = "1.13.0"
 fastrand = "2.3.0"
 milli = { path = "../milli" }
+scoped_thread_pool = { version = "0.1.0", path = "../../../../../../../dev/scoped_thread_pool" }
 serde = { version = "1.0.217", features = ["derive"] }
 serde_json = { version = "1.0.135", features = ["preserve_order"] }
 tempfile = "3.15.0"

crates/fuzzers/src/bin/fuzz-indexing.rs

@@ -12,6 +12,7 @@ use milli::documents::mmap_from_objects;
 use milli::heed::EnvOpenOptions;
 use milli::progress::Progress;
 use milli::update::new::indexer;
+use milli::update::new::indexer::document_changes::CHUNK_SIZE;
 use milli::update::{IndexDocumentsMethod, IndexerConfig};
 use milli::vector::EmbeddingConfigs;
 use milli::Index;
@@ -121,6 +122,11 @@ fn main() {
                                 }
                             }
 
+                            let thread_pool =
+                                scoped_thread_pool::ThreadPool::with_available_parallelism(
+                                    "index".into(),
+                                );
+
                             let (document_changes, _operation_stats, primary_key) = indexer
                                 .into_changes(
                                     &indexer_alloc,
@@ -130,12 +136,15 @@ fn main() {
                                     &mut new_fields_ids_map,
                                     &|| false,
                                     Progress::default(),
+                                    &thread_pool,
+                                    CHUNK_SIZE,
                                 )
                                 .unwrap();
 
                             indexer::index(
                                 &mut wtxn,
                                 &index,
+                                &thread_pool,
                                 &milli::ThreadPoolNoAbortBuilder::new().build().unwrap(),
                                 indexer_config.grenad_parameters(),
                                 &db_fields_ids_map,

crates/index-scheduler/Cargo.toml

@@ -28,6 +28,7 @@ memmap2 = "0.9.5"
 page_size = "0.6.0"
 rayon = "1.10.0"
 roaring = { version = "0.10.10", features = ["serde"] }
+scoped_thread_pool = { version = "0.1.0", path = "../../../../../../../dev/scoped_thread_pool" }
 serde = { version = "1.0.217", features = ["derive"] }
 serde_json = { version = "1.0.135", features = ["preserve_order"] }
 synchronoise = "1.0.1"

crates/index-scheduler/src/scheduler/process_index_operation.rs

@@ -3,6 +3,7 @@ use bumpalo::Bump;
 use meilisearch_types::heed::RwTxn;
 use meilisearch_types::milli::documents::PrimaryKey;
 use meilisearch_types::milli::progress::Progress;
+use meilisearch_types::milli::update::new::indexer::document_changes::CHUNK_SIZE;
 use meilisearch_types::milli::update::new::indexer::{self, UpdateByFunction};
 use meilisearch_types::milli::update::DocumentAdditionResult;
 use meilisearch_types::milli::{self, Filter, ThreadPoolNoAbortBuilder};
@@ -112,17 +113,24 @@ impl IndexScheduler {
 
                 let local_pool;
                 let indexer_config = self.index_mapper.indexer_config();
-                let pool = match &indexer_config.thread_pool {
+                let pool = match &indexer_config.rayon_thread_pool {
                     Some(pool) => pool,
                     None => {
                         local_pool = ThreadPoolNoAbortBuilder::new()
-                            .thread_name(|i| format!("indexing-thread-{i}"))
+                            .thread_name(|i| format!("rayon-{i}"))
                             .build()
                             .unwrap();
                         &local_pool
                     }
                 };
 
+                let thread_pool = match &indexer_config.thread_pool {
+                    Some(thread_pool) => thread_pool,
+                    None => {
+                        &scoped_thread_pool::ThreadPool::with_available_parallelism("index".into())
+                    }
+                };
+
                 progress.update_progress(DocumentOperationProgress::ComputingDocumentChanges);
                 let (document_changes, operation_stats, primary_key) = indexer
                     .into_changes(
@@ -133,6 +141,8 @@ impl IndexScheduler {
                         &mut new_fields_ids_map,
                         &|| must_stop_processing.get(),
                         progress.clone(),
+                        thread_pool,
+                        CHUNK_SIZE,
                     )
                     .map_err(|e| Error::from_milli(e, Some(index_uid.clone())))?;
 
@@ -173,6 +183,7 @@ impl IndexScheduler {
                     indexer::index(
                         index_wtxn,
                         index,
+                        thread_pool,
                         pool,
                         indexer_config.grenad_parameters(),
                         &db_fields_ids_map,
@@ -261,7 +272,7 @@ impl IndexScheduler {
                 if task.error.is_none() {
                     let local_pool;
                     let indexer_config = self.index_mapper.indexer_config();
-                    let pool = match &indexer_config.thread_pool {
+                    let pool = match &indexer_config.rayon_thread_pool {
                         Some(pool) => pool,
                         None => {
                             local_pool = ThreadPoolNoAbortBuilder::new()
@@ -272,16 +283,19 @@ impl IndexScheduler {
                         }
                     };
 
+                    let thread_pool = match &indexer_config.thread_pool {
+                        Some(thread_pool) => thread_pool,
+                        None => &scoped_thread_pool::ThreadPool::with_available_parallelism(
+                            "index".into(),
+                        ),
+                    };
+
                     let candidates_count = candidates.len();
                     progress.update_progress(DocumentEditionProgress::ComputingDocumentChanges);
                     let indexer = UpdateByFunction::new(candidates, context.clone(), code.clone());
-                    let document_changes = pool
+                    let document_changes = indexer
-                        .install(|| {
+                        .into_changes(&primary_key, &indexer_alloc, thread_pool, CHUNK_SIZE)
-                            indexer
+                        .map_err(|err| Error::from_milli(err, Some(index_uid.clone())))?;
-                                .into_changes(&primary_key)
-                                .map_err(|err| Error::from_milli(err, Some(index_uid.clone())))
-                        })
-                        .unwrap()?;
                     let embedders = index
                         .embedding_configs(index_wtxn)
                         .map_err(|err| Error::from_milli(err, Some(index_uid.clone())))?;
@@ -291,6 +305,7 @@ impl IndexScheduler {
                     indexer::index(
                         index_wtxn,
                         index,
+                        thread_pool,
                         pool,
                         indexer_config.grenad_parameters(),
                         &db_fields_ids_map,
@@ -421,7 +436,7 @@ impl IndexScheduler {
                 if !tasks.iter().all(|res| res.error.is_some()) {
                     let local_pool;
                     let indexer_config = self.index_mapper.indexer_config();
-                    let pool = match &indexer_config.thread_pool {
+                    let pool = match &indexer_config.rayon_thread_pool {
                         Some(pool) => pool,
                         None => {
                             local_pool = ThreadPoolNoAbortBuilder::new()
@@ -432,11 +447,19 @@ impl IndexScheduler {
                         }
                     };
 
+                    let thread_pool = match &indexer_config.thread_pool {
+                        Some(thread_pool) => thread_pool,
+                        None => &scoped_thread_pool::ThreadPool::with_available_parallelism(
+                            "index".into(),
+                        ),
+                    };
+
                     progress.update_progress(DocumentDeletionProgress::DeleteDocuments);
                     let mut indexer = indexer::DocumentDeletion::new();
                     let candidates_count = to_delete.len();
                     indexer.delete_documents_by_docids(to_delete);
-                    let document_changes = indexer.into_changes(&indexer_alloc, primary_key);
+                    let document_changes =
+                        indexer.into_changes(&indexer_alloc, primary_key, thread_pool, CHUNK_SIZE);
                     let embedders = index
                         .embedding_configs(index_wtxn)
                         .map_err(|err| Error::from_milli(err, Some(index_uid.clone())))?;
@@ -446,6 +469,7 @@ impl IndexScheduler {
                     indexer::index(
                         index_wtxn,
                         index,
+                        thread_pool,
                         pool,
                         indexer_config.grenad_parameters(),
                         &db_fields_ids_map,

crates/meilisearch/Cargo.toml

@@ -115,6 +115,7 @@ utoipa = { version = "5.3.1", features = [
     "openapi_extensions",
 ] }
 utoipa-scalar = { version = "0.3.0", optional = true, features = ["actix-web"] }
+scoped_thread_pool = { version = "0.1.0", path = "../../../../../../../dev/scoped_thread_pool" }
 
 [dev-dependencies]
 actix-rt = "2.10.0"

crates/meilisearch/src/option.rs

@@ -743,15 +743,21 @@ impl TryFrom<&IndexerOpts> for IndexerConfig {
     type Error = anyhow::Error;
 
     fn try_from(other: &IndexerOpts) -> Result<Self, Self::Error> {
-        let thread_pool = ThreadPoolNoAbortBuilder::new()
+        let rayon_thread_pool = ThreadPoolNoAbortBuilder::new()
-            .thread_name(|index| format!("indexing-thread:{index}"))
+            .thread_name(|index| format!("rayon-{index}"))
             .num_threads(*other.max_indexing_threads)
             .build()?;
 
+        let thread_pool = Some(scoped_thread_pool::ThreadPool::new(
+            NonZeroUsize::new(*other.max_indexing_threads).unwrap_or(NonZeroUsize::new(1).unwrap()),
+            "index".to_string(),
+        ));
+
         Ok(Self {
             log_every_n: Some(DEFAULT_LOG_EVERY_N),
             max_memory: other.max_indexing_memory.map(|b| b.as_u64() as usize),
-            thread_pool: Some(thread_pool),
+            rayon_thread_pool: Some(rayon_thread_pool),
+            thread_pool,
             max_positions_per_attributes: None,
             skip_index_budget: other.skip_index_budget,
             ..Default::default()

crates/milli/Cargo.toml

@@ -1,116 +1,117 @@
 [package]
-name = "milli"
 edition = "2021"
+name = "milli"
 publish = false
 
-version.workspace = true
 authors.workspace = true
 description.workspace = true
 homepage.workspace = true
 readme.workspace = true
+version.workspace = true
 # edition.workspace = true
 license.workspace = true
 
 [dependencies]
 big_s = "1.0.2"
-bimap = { version = "0.6.3", features = ["serde"] }
+bimap = {version = "0.6.3", features = ["serde"]}
 bincode = "1.3.3"
 bstr = "1.11.3"
-bytemuck = { version = "1.21.0", features = ["extern_crate_alloc"] }
+bytemuck = {version = "1.21.0", features = ["extern_crate_alloc"]}
 byteorder = "1.5.0"
-charabia = { version = "0.9.2", default-features = false }
+charabia = {version = "0.9.2", default-features = false}
 concat-arrays = "0.1.2"
 convert_case = "0.6.0"
 crossbeam-channel = "0.5.14"
 deserr = "0.6.3"
-either = { version = "1.13.0", features = ["serde"] }
+either = {version = "1.13.0", features = ["serde"]}
-flatten-serde-json = { path = "../flatten-serde-json" }
+flatten-serde-json = {path = "../flatten-serde-json"}
 fst = "0.4.7"
 fxhash = "0.2.1"
 geoutils = "0.5.1"
-grenad = { version = "0.5.0", default-features = false, features = ["rayon", "tempfile"] }
+grenad = {version = "0.5.0", default-features = false, features = ["rayon", "tempfile"]}
-heed = { version = "0.20.5", default-features = false, features = [
+heed = {version = "0.20.5", default-features = false, features = [
   "serde-json",
   "serde-bincode",
   "read-txn-no-tls",
-] }
+]}
-indexmap = { version = "2.7.0", features = ["serde"] }
+indexmap = {version = "2.7.0", features = ["serde"]}
-json-depth-checker = { path = "../json-depth-checker" }
+json-depth-checker = {path = "../json-depth-checker"}
-levenshtein_automata = { version = "0.2.1", features = ["fst_automaton"] }
+levenshtein_automata = {version = "0.2.1", features = ["fst_automaton"]}
 memchr = "2.7.4"
 memmap2 = "0.9.5"
 obkv = "0.3.0"
 once_cell = "1.20.2"
 ordered-float = "4.6.0"
 rayon = "1.10.0"
-roaring = { version = "0.10.10", features = ["serde"] }
+roaring = {version = "0.10.10", features = ["serde"]}
-rstar = { version = "0.12.2", features = ["serde"] }
+rstar = {version = "0.12.2", features = ["serde"]}
-serde = { version = "1.0.217", features = ["derive"] }
+serde = {version = "1.0.217", features = ["derive"]}
-serde_json = { version = "1.0.135", features = ["preserve_order", "raw_value"] }
+serde_json = {version = "1.0.135", features = ["preserve_order", "raw_value"]}
 slice-group-by = "0.3.1"
-smallstr = { version = "0.3.0", features = ["serde"] }
+smallstr = {version = "0.3.0", features = ["serde"]}
 smallvec = "1.13.2"
 smartstring = "1.0.1"
 tempfile = "3.15.0"
 thiserror = "2.0.9"
-time = { version = "0.3.37", features = [
+time = {version = "0.3.37", features = [
   "serde-well-known",
   "formatting",
   "parsing",
   "macros",
-] }
+]}
-uuid = { version = "1.11.0", features = ["v4"] }
+uuid = {version = "1.11.0", features = ["v4"]}
 
-filter-parser = { path = "../filter-parser" }
+filter-parser = {path = "../filter-parser"}
+scoped_thread_pool = {path = "/home/dureuill/dev/scoped_thread_pool"}
 
 # documents words self-join
 itertools = "0.14.0"
 
+allocator-api2 = "0.2.21"
+arroy = "0.5.0"
+bbqueue = {git = "https://github.com/meilisearch/bbqueue"}
+bumpalo = "3.16.0"
+bumparaw-collections = "0.1.4"
+candle-core = {version = "0.8.2"}
+candle-nn = {version = "0.8.2"}
+candle-transformers = {version = "0.8.2"}
 csv = "1.3.1"
-candle-core = { version = "0.8.2" }
+enum-iterator = "2.1.0"
-candle-transformers = { version = "0.8.2" }
+flume = {version = "0.11.1", default-features = false}
-candle-nn = { version = "0.8.2" }
+hashbrown = "0.15.2"
-tokenizers = { git = "https://github.com/huggingface/tokenizers.git", tag = "v0.15.2", version = "0.15.2", default-features = false, features = [
+hf-hub = {git = "https://github.com/dureuill/hf-hub.git", branch = "rust_tls", default-features = false, features = [
-    "onig",
-] }
-hf-hub = { git = "https://github.com/dureuill/hf-hub.git", branch = "rust_tls", default-features = false, features = [
   "online",
-] }
+]}
-tiktoken-rs = "0.6.0"
 liquid = "0.26.9"
-rhai = { git = "https://github.com/rhaiscript/rhai", rev = "ef3df63121d27aacd838f366f2b83fd65f20a1e4", features = [
+rand = "0.8.5"
+rayon-par-bridge = "0.1.0"
+rhai = {git = "https://github.com/rhaiscript/rhai", rev = "ef3df63121d27aacd838f366f2b83fd65f20a1e4", features = [
   "serde",
   "no_module",
   "no_custom_syntax",
   "no_time",
   "sync",
-] }
+]}
-arroy = "0.5.0"
-rand = "0.8.5"
-tracing = "0.1.41"
-ureq = { version = "2.12.1", features = ["json"] }
-url = "2.5.4"
-rayon-par-bridge = "0.1.0"
-hashbrown = "0.15.2"
-bumpalo = "3.16.0"
-bumparaw-collections = "0.1.4"
-thread_local = "1.1.8"
-allocator-api2 = "0.2.21"
 rustc-hash = "2.1.0"
+thread_local = "1.1.8"
+tiktoken-rs = "0.6.0"
+tokenizers = {git = "https://github.com/huggingface/tokenizers.git", tag = "v0.15.2", version = "0.15.2", default-features = false, features = [
+  "onig",
+]}
+tracing = "0.1.41"
 uell = "0.1.0"
-enum-iterator = "2.1.0"
+ureq = {version = "2.12.1", features = ["json"]}
-bbqueue = { git = "https://github.com/meilisearch/bbqueue" }
+url = "2.5.4"
-flume = { version = "0.11.1", default-features = false }
+utoipa = {version = "5.3.1", features = ["non_strict_integers", "preserve_order", "uuid", "time", "openapi_extensions"]}
-utoipa = { version = "5.3.1", features = ["non_strict_integers", "preserve_order", "uuid", "time", "openapi_extensions"] }
 
 [dev-dependencies]
-mimalloc = { version = "0.1.43", default-features = false }
+mimalloc = {version = "0.1.43", default-features = false}
 # fixed version due to format breakages in v1.40
 insta = "=1.39.0"
 maplit = "1.0.2"
 md5 = "0.7.0"
-meili-snap = { path = "../meili-snap" }
+meili-snap = {path = "../meili-snap"}
-rand = { version = "0.8.5", features = ["small_rng"] }
+rand = {version = "0.8.5", features = ["small_rng"]}
 
 [features]
 all-tokenizations = [

crates/milli/src/error.rs

@@ -515,3 +515,68 @@ fn conditionally_lookup_for_error_message() {
         assert_eq!(err.to_string(), format!("{} {}", prefix, suffix));
     }
 }
+
+impl Error {
+    pub fn from_scoped_thread_pool_error(
+        thread_pool: &scoped_thread_pool::ThreadPool<Self>,
+        thread_id: usize,
+        error: scoped_thread_pool::Error<Self>,
+    ) -> Self {
+        match error {
+            scoped_thread_pool::Error::Err(error) => error,
+            scoped_thread_pool::Error::Panic(payload)
+            | scoped_thread_pool::Error::ThreadExited(Some(payload)) => {
+                let msg = match payload.downcast_ref::<&'static str>() {
+                    Some(s) => *s,
+                    None => match payload.downcast_ref::<String>() {
+                        Some(s) => &s[..],
+                        None => "Box<dyn Any>",
+                    },
+                };
+                tracing::error!(
+                    thread_name = thread_pool.thread_name(thread_id),
+                    "Thread panicked with {msg}"
+                );
+                Error::InternalError(InternalError::PanicInThreadPool(PanicCatched))
+            }
+            scoped_thread_pool::Error::ThreadExited(None) => {
+                Error::InternalError(InternalError::PanicInThreadPool(PanicCatched))
+            }
+        }
+    }
+
+    pub fn from_scoped_thread_pool_errors(
+        thread_pool: &scoped_thread_pool::ThreadPool<Self>,
+        value: scoped_thread_pool::Errors<Error>,
+    ) -> Self {
+        // iterate all errors, keeping the "max" one
+        // such that AbortedIndexing < regular error < panic
+        let mut max = None;
+        for (thread_id, error) in value.0 {
+            max = match (max, error) {
+                (None, error) => Some((thread_id, error)),
+                (max @ Some((_, scoped_thread_pool::Error::Panic(_))), _) => max,
+                (_, new @ scoped_thread_pool::Error::Panic(_)) => Some((thread_id, new)),
+                (max @ Some((_, scoped_thread_pool::Error::ThreadExited(Some(_)))), _) => max,
+                (_, new @ scoped_thread_pool::Error::ThreadExited(Some(_))) => {
+                    Some((thread_id, new))
+                }
+                (max @ Some((_, scoped_thread_pool::Error::ThreadExited(None))), _) => max,
+                (_, new @ scoped_thread_pool::Error::ThreadExited(None)) => Some((thread_id, new)),
+                (
+                    Some((
+                        _,
+                        scoped_thread_pool::Error::Err(Error::InternalError(
+                            InternalError::AbortedIndexation,
+                        )),
+                    )),
+                    new,
+                ) => Some((thread_id, new)),
+                (max @ Some((_, scoped_thread_pool::Error::Err(_))), _) => max,
+            };
+        }
+        // Errors never have an empty list
+        let (thread_id, error) = max.unwrap();
+        Self::from_scoped_thread_pool_error(thread_pool, thread_id, error)
+    }
+}

crates/milli/src/index.rs

@@ -1788,6 +1788,7 @@ pub(crate) mod tests {
     use crate::index::{DEFAULT_MIN_WORD_LEN_ONE_TYPO, DEFAULT_MIN_WORD_LEN_TWO_TYPOS};
     use crate::progress::Progress;
     use crate::update::new::indexer;
+    use crate::update::new::indexer::document_changes::CHUNK_SIZE;
     use crate::update::settings::InnerIndexSettings;
     use crate::update::{
         self, IndexDocumentsConfig, IndexDocumentsMethod, IndexerConfig, Setting, Settings,
@@ -1837,7 +1838,7 @@ pub(crate) mod tests {
         ) -> Result<(), crate::error::Error> {
             let local_pool;
             let indexer_config = &self.indexer_config;
-            let pool = match &indexer_config.thread_pool {
+            let pool = match &indexer_config.rayon_thread_pool {
                 Some(pool) => pool,
                 None => {
                     local_pool = ThreadPoolNoAbortBuilder::new().build().unwrap();
@@ -1845,6 +1846,11 @@ pub(crate) mod tests {
                 }
             };
 
+            let thread_pool = match &indexer_config.thread_pool {
+                Some(thread_pool) => thread_pool,
+                None => &scoped_thread_pool::ThreadPool::with_available_parallelism("index".into()),
+            };
+
             let rtxn = self.inner.read_txn()?;
             let db_fields_ids_map = self.inner.fields_ids_map(&rtxn)?;
             let mut new_fields_ids_map = db_fields_ids_map.clone();
@@ -1864,17 +1870,19 @@ pub(crate) mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                thread_pool,
+                CHUNK_SIZE,
             )?;
 
             if let Some(error) = operation_stats.into_iter().find_map(|stat| stat.error) {
                 return Err(error.into());
             }
 
-            pool.install(|| {
             indexer::index(
                 wtxn,
                 &self.inner,
-                    &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
+                thread_pool,
+                &pool,
                 indexer_config.grenad_parameters(),
                 &db_fields_ids_map,
                 new_fields_ids_map,
@@ -1883,10 +1891,7 @@ pub(crate) mod tests {
                 embedders,
                 &|| false,
                 &Progress::default(),
-                )
+            )?;
-            })
-            .unwrap()?;
-
             Ok(())
         }
 
@@ -1925,7 +1930,7 @@ pub(crate) mod tests {
         ) -> Result<(), crate::error::Error> {
             let local_pool;
             let indexer_config = &self.indexer_config;
-            let pool = match &indexer_config.thread_pool {
+            let pool = match &indexer_config.rayon_thread_pool {
                 Some(pool) => pool,
                 None => {
                     local_pool = ThreadPoolNoAbortBuilder::new().build().unwrap();
@@ -1933,6 +1938,11 @@ pub(crate) mod tests {
                 }
             };
 
+            let thread_pool = match &indexer_config.thread_pool {
+                Some(thread_pool) => thread_pool,
+                None => &scoped_thread_pool::ThreadPool::with_available_parallelism("index".into()),
+            };
+
             let rtxn = self.inner.read_txn()?;
             let db_fields_ids_map = self.inner.fields_ids_map(&rtxn)?;
             let mut new_fields_ids_map = db_fields_ids_map.clone();
@@ -1955,17 +1965,19 @@ pub(crate) mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                thread_pool,
+                CHUNK_SIZE,
             )?;
 
             if let Some(error) = operation_stats.into_iter().find_map(|stat| stat.error) {
                 return Err(error.into());
             }
 
-            pool.install(|| {
             indexer::index(
                 wtxn,
                 &self.inner,
-                    &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
+                thread_pool,
+                &pool,
                 indexer_config.grenad_parameters(),
                 &db_fields_ids_map,
                 new_fields_ids_map,
@@ -1974,9 +1986,7 @@ pub(crate) mod tests {
                 embedders,
                 &|| false,
                 &Progress::default(),
-                )
+            )?;
-            })
-            .unwrap()?;
 
             Ok(())
         }
@@ -2005,7 +2015,7 @@ pub(crate) mod tests {
 
         let local_pool;
         let indexer_config = &index.indexer_config;
-        let pool = match &indexer_config.thread_pool {
+        let pool = match &indexer_config.rayon_thread_pool {
             Some(pool) => pool,
             None => {
                 local_pool = ThreadPoolNoAbortBuilder::new().build().unwrap();
@@ -2013,6 +2023,11 @@ pub(crate) mod tests {
             }
         };
 
+        let thread_pool = match &indexer_config.thread_pool {
+            Some(thread_pool) => thread_pool,
+            None => &scoped_thread_pool::ThreadPool::with_available_parallelism("index".into()),
+        };
+
         let rtxn = index.inner.read_txn().unwrap();
         let db_fields_ids_map = index.inner.fields_ids_map(&rtxn).unwrap();
         let mut new_fields_ids_map = db_fields_ids_map.clone();
@@ -2036,6 +2051,8 @@ pub(crate) mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
@@ -2046,7 +2063,8 @@ pub(crate) mod tests {
                 indexer::index(
                     &mut wtxn,
                     &index.inner,
-                    &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
+                    thread_pool,
+                    &pool,
                     indexer_config.grenad_parameters(),
                     &db_fields_ids_map,
                     new_fields_ids_map,

crates/milli/src/search/new/tests/integration.rs

@@ -7,6 +7,7 @@ use maplit::{btreemap, hashset};
 
 use crate::progress::Progress;
 use crate::update::new::indexer;
+use crate::update::new::indexer::document_changes::CHUNK_SIZE;
 use crate::update::{IndexDocumentsMethod, IndexerConfig, Settings};
 use crate::vector::EmbeddingConfigs;
 use crate::{db_snap, Criterion, Index};
@@ -65,6 +66,9 @@ pub fn setup_search_index_with_criteria(criteria: &[Criterion]) -> Index {
     // index documents
     indexer.add_documents(&payload).unwrap();
 
+    let thread_pool =
+        scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
+
     let indexer_alloc = Bump::new();
     let (document_changes, operation_stats, primary_key) = indexer
         .into_changes(
@@ -75,6 +79,8 @@ pub fn setup_search_index_with_criteria(criteria: &[Criterion]) -> Index {
             &mut new_fields_ids_map,
             &|| false,
             Progress::default(),
+            &thread_pool,
+            CHUNK_SIZE,
         )
         .unwrap();
 
@@ -85,6 +91,7 @@ pub fn setup_search_index_with_criteria(criteria: &[Criterion]) -> Index {
     indexer::index(
         &mut wtxn,
         &index,
+        &thread_pool,
         &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
         config.grenad_parameters(),
         &db_fields_ids_map,

crates/milli/src/update/index_documents/extract/extract_docid_word_positions.rs

@@ -28,7 +28,7 @@ pub fn extract_docid_word_positions<R: io::Read + io::Seek>(
 ) -> Result<grenad::Reader<BufReader<File>>> {
     let max_positions_per_attributes = max_positions_per_attributes
         .map_or(MAX_POSITION_PER_ATTRIBUTE, |max| max.min(MAX_POSITION_PER_ATTRIBUTE));
-    let max_memory = indexer.max_memory_by_thread();
+    let max_memory = indexer.max_memory_by_rayon_thread();
     let force_reindexing = settings_diff.reindex_searchable();
 
     // initialize destination values.

crates/milli/src/update/index_documents/extract/extract_facet_number_docids.rs

@@ -23,7 +23,7 @@ pub fn extract_facet_number_docids<R: io::Read + io::Seek>(
     indexer: GrenadParameters,
     _settings_diff: &InnerIndexSettingsDiff,
 ) -> Result<grenad::Reader<BufReader<File>>> {
-    let max_memory = indexer.max_memory_by_thread();
+    let max_memory = indexer.max_memory_by_rayon_thread();
 
     let mut facet_number_docids_sorter = create_sorter(
         grenad::SortAlgorithm::Unstable,

crates/milli/src/update/index_documents/extract/extract_facet_string_docids.rs

@@ -55,7 +55,7 @@ fn extract_facet_string_docids_document_update<R: io::Read + io::Seek>(
     localized_field_ids: &LocalizedFieldIds,
     facet_search: bool,
 ) -> Result<(grenad::Reader<BufReader<File>>, grenad::Reader<BufReader<File>>)> {
-    let max_memory = indexer.max_memory_by_thread();
+    let max_memory = indexer.max_memory_by_rayon_thread();
 
     let mut facet_string_docids_sorter = create_sorter(
         grenad::SortAlgorithm::Stable,
@@ -145,7 +145,7 @@ fn extract_facet_string_docids_settings<R: io::Read + io::Seek>(
     indexer: GrenadParameters,
     settings_diff: &InnerIndexSettingsDiff,
 ) -> Result<(grenad::Reader<BufReader<File>>, grenad::Reader<BufReader<File>>)> {
-    let max_memory = indexer.max_memory_by_thread();
+    let max_memory = indexer.max_memory_by_rayon_thread();
 
     let mut facet_string_docids_sorter = create_sorter(
         grenad::SortAlgorithm::Stable,

crates/milli/src/update/index_documents/extract/extract_fid_docid_facet_values.rs

@@ -44,7 +44,7 @@ pub fn extract_fid_docid_facet_values<R: io::Read + io::Seek>(
     indexer: GrenadParameters,
     settings_diff: &InnerIndexSettingsDiff,
 ) -> Result<ExtractedFacetValues> {
-    let max_memory = indexer.max_memory_by_thread();
+    let max_memory = indexer.max_memory_by_rayon_thread();
 
     let mut fid_docid_facet_numbers_sorter = create_sorter(
         grenad::SortAlgorithm::Stable,

crates/milli/src/update/index_documents/extract/extract_fid_word_count_docids.rs

@@ -26,7 +26,7 @@ pub fn extract_fid_word_count_docids<R: io::Read + io::Seek>(
     indexer: GrenadParameters,
     _settings_diff: &InnerIndexSettingsDiff,
 ) -> Result<grenad::Reader<BufReader<File>>> {
-    let max_memory = indexer.max_memory_by_thread();
+    let max_memory = indexer.max_memory_by_rayon_thread();
 
     let mut fid_word_count_docids_sorter = create_sorter(
         grenad::SortAlgorithm::Unstable,

crates/milli/src/update/index_documents/extract/extract_word_docids.rs

@@ -35,7 +35,7 @@ pub fn extract_word_docids<R: io::Read + io::Seek>(
     grenad::Reader<BufReader<File>>,
     grenad::Reader<BufReader<File>>,
 )> {
-    let max_memory = indexer.max_memory_by_thread();
+    let max_memory = indexer.max_memory_by_rayon_thread();
 
     let mut word_fid_docids_sorter = create_sorter(
         grenad::SortAlgorithm::Unstable,

crates/milli/src/update/index_documents/extract/extract_word_pair_proximity_docids.rs

@@ -39,7 +39,7 @@ pub fn extract_word_pair_proximity_docids<R: io::Read + io::Seek>(
     let any_deletion = settings_diff.old.proximity_precision == ProximityPrecision::ByWord;
     let any_addition = settings_diff.new.proximity_precision == ProximityPrecision::ByWord;
 
-    let max_memory = indexer.max_memory_by_thread();
+    let max_memory = indexer.max_memory_by_rayon_thread();
     let mut word_pair_proximity_docids_sorters: Vec<_> = (1..MAX_DISTANCE)
         .map(|_| {
             create_sorter(

crates/milli/src/update/index_documents/extract/extract_word_position_docids.rs

@@ -24,7 +24,7 @@ pub fn extract_word_position_docids<R: io::Read + io::Seek>(
     indexer: GrenadParameters,
     _settings_diff: &InnerIndexSettingsDiff,
 ) -> Result<grenad::Reader<BufReader<File>>> {
-    let max_memory = indexer.max_memory_by_thread();
+    let max_memory = indexer.max_memory_by_rayon_thread();
 
     let mut word_position_docids_sorter = create_sorter(
         grenad::SortAlgorithm::Unstable,

crates/milli/src/update/index_documents/helpers/grenad_helpers.rs

@@ -119,7 +119,11 @@ impl GrenadParameters {
     ///
     /// This should be called inside of a rayon thread pool,
     /// otherwise, it will take the global number of threads.
-    pub fn max_memory_by_thread(&self) -> Option<usize> {
+    pub fn max_memory_by_thread(&self, thread_count: usize) -> Option<usize> {
+        self.max_memory.map(|max_memory| (max_memory / thread_count))
+    }
+
+    pub fn max_memory_by_rayon_thread(&self) -> Option<usize> {
         self.max_memory.map(|max_memory| (max_memory / rayon::current_num_threads()))
     }
 }

crates/milli/src/update/index_documents/mod.rs

@@ -227,7 +227,7 @@ where
             crate::vector::error::PossibleEmbeddingMistakes::new(&field_distribution);
 
         let backup_pool;
-        let pool = match self.indexer_config.thread_pool {
+        let pool = match self.indexer_config.rayon_thread_pool {
             Some(ref pool) => pool,
             None => {
                 // We initialize a backup pool with the default
@@ -770,6 +770,7 @@ mod tests {
     use crate::progress::Progress;
     use crate::search::TermsMatchingStrategy;
     use crate::update::new::indexer;
+    use crate::update::new::indexer::document_changes::CHUNK_SIZE;
     use crate::update::Setting;
     use crate::{db_snap, Filter, Search, UserError};
 
@@ -1967,6 +1968,8 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string()),
+                CHUNK_SIZE,
             )
             .unwrap();
 
@@ -2115,6 +2118,9 @@ mod tests {
         let mut indexer = indexer::DocumentOperation::new(IndexDocumentsMethod::ReplaceDocuments);
         indexer.add_documents(&documents).unwrap();
         indexer.delete_documents(&["2"]);
+
+        let thread_pool =
+            scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
         let (document_changes, _operation_stats, primary_key) = indexer
             .into_changes(
                 &indexer_alloc,
@@ -2124,12 +2130,15 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
         indexer::index(
             &mut wtxn,
             &index.inner,
+            &thread_pool,
             &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
             indexer_config.grenad_parameters(),
             &db_fields_ids_map,
@@ -2177,6 +2186,9 @@ mod tests {
 
         let indexer_alloc = Bump::new();
         let embedders = EmbeddingConfigs::default();
+        let thread_pool =
+            scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
+
         let (document_changes, _operation_stats, primary_key) = indexer
             .into_changes(
                 &indexer_alloc,
@@ -2186,12 +2198,15 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
         indexer::index(
             &mut wtxn,
             &index.inner,
+            &thread_pool,
             &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
             indexer_config.grenad_parameters(),
             &db_fields_ids_map,
@@ -2229,6 +2244,8 @@ mod tests {
         let embedders = EmbeddingConfigs::default();
         let mut indexer = indexer::DocumentOperation::new(IndexDocumentsMethod::UpdateDocuments);
         indexer.add_documents(&documents).unwrap();
+        let thread_pool =
+            scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
 
         let (document_changes, _operation_stats, primary_key) = indexer
             .into_changes(
@@ -2239,12 +2256,15 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
         indexer::index(
             &mut wtxn,
             &index.inner,
+            &thread_pool,
             &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
             indexer_config.grenad_parameters(),
             &db_fields_ids_map,
@@ -2291,12 +2311,15 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
         indexer::index(
             &mut wtxn,
             &index.inner,
+            &thread_pool,
             &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
             indexer_config.grenad_parameters(),
             &db_fields_ids_map,
@@ -2327,6 +2350,8 @@ mod tests {
 
         let indexer_alloc = Bump::new();
         let embedders = EmbeddingConfigs::default();
+        let thread_pool =
+            scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
         let mut indexer = indexer::DocumentOperation::new(IndexDocumentsMethod::UpdateDocuments);
         indexer.delete_documents(&["1", "2"]);
 
@@ -2345,12 +2370,15 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
         indexer::index(
             &mut wtxn,
             &index.inner,
+            &thread_pool,
             &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
             indexer_config.grenad_parameters(),
             &db_fields_ids_map,
@@ -2382,6 +2410,8 @@ mod tests {
 
         let indexer_alloc = Bump::new();
         let embedders = EmbeddingConfigs::default();
+        let thread_pool =
+            scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
         let mut indexer = indexer::DocumentOperation::new(IndexDocumentsMethod::UpdateDocuments);
 
         indexer.delete_documents(&["1", "2", "1", "2"]);
@@ -2404,12 +2434,15 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
         indexer::index(
             &mut wtxn,
             &index.inner,
+            &thread_pool,
             &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
             indexer_config.grenad_parameters(),
             &db_fields_ids_map,
@@ -2440,6 +2473,8 @@ mod tests {
 
         let indexer_alloc = Bump::new();
         let embedders = EmbeddingConfigs::default();
+        let thread_pool =
+            scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
         let mut indexer = indexer::DocumentOperation::new(IndexDocumentsMethod::UpdateDocuments);
 
         let documents = documents!([
@@ -2456,12 +2491,15 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
         indexer::index(
             &mut wtxn,
             &index.inner,
+            &thread_pool,
             &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
             indexer_config.grenad_parameters(),
             &db_fields_ids_map,
@@ -2508,12 +2546,15 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
         indexer::index(
             &mut wtxn,
             &index.inner,
+            &thread_pool,
             &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
             indexer_config.grenad_parameters(),
             &db_fields_ids_map,
@@ -2683,6 +2724,8 @@ mod tests {
 
         let indexer_alloc = Bump::new();
         let embedders = EmbeddingConfigs::default();
+        let thread_pool =
+            scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
         let mut indexer = indexer::DocumentOperation::new(IndexDocumentsMethod::ReplaceDocuments);
 
         // OP
@@ -2702,12 +2745,15 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
         indexer::index(
             &mut wtxn,
             &index.inner,
+            &thread_pool,
             &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
             indexer_config.grenad_parameters(),
             &db_fields_ids_map,
@@ -2761,12 +2807,15 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
         indexer::index(
             &mut wtxn,
             &index.inner,
+            &thread_pool,
             &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
             indexer_config.grenad_parameters(),
             &db_fields_ids_map,
@@ -2817,12 +2866,15 @@ mod tests {
                 &mut new_fields_ids_map,
                 &|| false,
                 Progress::default(),
+                &thread_pool,
+                CHUNK_SIZE,
             )
             .unwrap();
 
         indexer::index(
             &mut wtxn,
             &index.inner,
+            &thread_pool,
             &crate::ThreadPoolNoAbortBuilder::new().build().unwrap(),
             indexer_config.grenad_parameters(),
             &db_fields_ids_map,

crates/milli/src/update/indexer_config.rs

@@ -11,7 +11,8 @@ pub struct IndexerConfig {
     pub max_memory: Option<usize>,
     pub chunk_compression_type: CompressionType,
     pub chunk_compression_level: Option<u32>,
-    pub thread_pool: Option<ThreadPoolNoAbort>,
+    pub rayon_thread_pool: Option<ThreadPoolNoAbort>,
+    pub thread_pool: Option<scoped_thread_pool::ThreadPool<crate::Error>>,
     pub max_positions_per_attributes: Option<u32>,
     pub skip_index_budget: bool,
 }
@@ -36,6 +37,7 @@ impl Default for IndexerConfig {
             max_memory: None,
             chunk_compression_type: CompressionType::None,
             chunk_compression_level: None,
+            rayon_thread_pool: None,
             thread_pool: None,
             max_positions_per_attributes: None,
             skip_index_budget: false,

crates/milli/src/update/new/channel.rs

@@ -51,12 +51,13 @@ const MAX_FRAME_HEADER_SIZE: usize = 9;
 /// when new stuff is available in any BBQueue buffer but we send
 /// a message in this queue only if it is empty to avoid filling
 /// the channel *and* the BBQueue.
-pub fn extractor_writer_bbqueue(
+pub fn extractor_writer_bbqueue<'a>(
-    bbbuffers: &mut Vec<BBBuffer>,
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
+    bbbuffers: &'a mut Vec<BBBuffer>,
     total_bbbuffer_capacity: usize,
     channel_capacity: usize,
-) -> (ExtractorBbqueueSender, WriterBbqueueReceiver) {
+) -> (ExtractorBbqueueSender<'a>, WriterBbqueueReceiver<'a>) {
-    let current_num_threads = rayon::current_num_threads();
+    let current_num_threads = thread_pool.thread_count();
     let bbbuffer_capacity = total_bbbuffer_capacity.checked_div(current_num_threads).unwrap();
     bbbuffers.resize_with(current_num_threads, || BBBuffer::new(bbbuffer_capacity));
 
@@ -66,12 +67,18 @@ pub fn extractor_writer_bbqueue(
     let max_grant = capacity.saturating_div(2).checked_sub(MAX_FRAME_HEADER_SIZE).unwrap();
 
     let producers = ThreadLocal::with_capacity(bbbuffers.len());
-    let consumers = rayon::broadcast(|bi| {
+    let consumers = ThreadLocal::with_capacity(bbbuffers.len());
-        let bbqueue = &bbbuffers[bi.index()];
+    thread_pool
+        .broadcast(|thread_index| {
+            let bbqueue: &BBBuffer = &bbbuffers[thread_index];
             let (producer, consumer) = bbqueue.try_split_framed().unwrap();
             producers.get_or(|| FullySend(RefCell::new(producer)));
-        consumer
+            consumers.get_or(|| FullySend(consumer));
-    });
+            Ok(())
+        })
+        .map_err(|errors| crate::Error::from_scoped_thread_pool_errors(thread_pool, errors))
+        .unwrap();
+    let consumers: Vec<_> = consumers.into_iter().map(|consumer| consumer.0).collect();
 
     let sent_messages_attempts = Arc::new(AtomicUsize::new(0));
     let blocking_sent_messages_attempts = Arc::new(AtomicUsize::new(0));
@@ -963,28 +970,70 @@ impl GeoSender<'_, '_> {
             .map_err(|_| SendError(()))
     }
 
-    pub fn set_geo_faceted(&self, bitmap: &RoaringBitmap) -> crate::Result<()> {
+    pub fn set_geo_faceted(
+        &self,
+        bitmap: &RoaringBitmap,
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
+    ) -> crate::Result<()> {
+        let writer = GeoWriter { bitmap, channel: *self };
+        thread_pool
+            .execute(&writer)
+            .map_err(|errors| crate::Error::from_scoped_thread_pool_errors(thread_pool, errors))
+    }
+}
+
+struct GeoWriter<'a, 'b> {
+    bitmap: &'a RoaringBitmap,
+    channel: GeoSender<'a, 'b>,
+}
+impl<'a, 'b> scoped_thread_pool::Workload<'static> for GeoWriter<'a, 'b> {
+    type Context = ();
+
+    type Error = crate::Error;
+
+    fn context(
+        &self,
+        _thread_count: usize,
+        _thread_index: usize,
+    ) -> Result<Self::Context, Self::Error> {
+        Ok(())
+    }
+
+    fn run_task(
+        &self,
+        _thread_count: usize,
+        thread_index: usize,
+        task_index: usize,
+        _context: &mut Self::Context,
+    ) -> Option<Result<(), Self::Error>> {
+        if thread_index != 0 || task_index != 0 {
+            return None;
+        }
         let database = Database::Main;
-        let value_length = bitmap.serialized_size();
+        let value_length = self.bitmap.serialized_size();
         let key = GEO_FACETED_DOCUMENTS_IDS_KEY.as_bytes();
-        let key_length = key.len().try_into().ok().and_then(NonZeroU16::new).ok_or_else(|| {
+        let key_length = match key.len().try_into().ok().and_then(NonZeroU16::new) {
-            InternalError::StorePut {
+            Some(key_length) => key_length,
+            None => {
+                return Some(Err(InternalError::StorePut {
                     database_name: database.database_name(),
                     key: key.into(),
                     value_length,
                     error: MdbError::BadValSize.into(),
                 }
-        })?;
+                .into()))
+            }
+        };
 
-        self.0.write_key_value_with(
+        Some(self.channel.0.write_key_value_with(
             database,
             key_length,
             value_length,
             |key_buffer, value_buffer| {
                 key_buffer.copy_from_slice(key);
-                bitmap.serialize_into(value_buffer)?;
+                self.bitmap.serialize_into(value_buffer)?;
                 Ok(())
             },
-        )
+        ))
     }
 }

crates/milli/src/update/new/extract/faceted/extract_facets.rs

@@ -38,7 +38,7 @@ impl<'a, 'b, 'extractor> Extractor<'extractor> for FacetedExtractorData<'a, 'b>
     fn init_data(&self, extractor_alloc: &'extractor Bump) -> Result<Self::Data> {
         Ok(RefCell::new(BalancedCaches::new_in(
             self.buckets,
-            self.grenad_parameters.max_memory_by_thread(),
+            self.grenad_parameters.max_memory_by_thread(self.buckets),
             extractor_alloc,
         )))
     }
@@ -388,6 +388,7 @@ fn truncate_str(s: &str) -> &str {
 impl FacetedDocidsExtractor {
     #[tracing::instrument(level = "trace", skip_all, target = "indexing::extract::faceted")]
     pub fn run_extraction<'pl, 'fid, 'indexer, 'index, 'extractor, DC: DocumentChanges<'pl>, MSP>(
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
         document_changes: &DC,
         indexing_context: IndexingContext<'fid, 'indexer, 'index, MSP>,
         extractor_allocs: &'extractor mut ThreadLocal<FullySend<Bump>>,
@@ -412,10 +413,11 @@ impl FacetedDocidsExtractor {
             let extractor = FacetedExtractorData {
                 attributes_to_extract: &attributes_to_extract,
                 grenad_parameters: indexing_context.grenad_parameters,
-                buckets: rayon::current_num_threads(),
+                buckets: thread_pool.thread_count(),
                 sender,
             };
             extract(
+                thread_pool,
                 document_changes,
                 &extractor,
                 indexing_context,

crates/milli/src/update/new/extract/geo/mod.rs

@@ -21,6 +21,7 @@ use crate::{lat_lng_to_xyz, DocumentId, GeoPoint, Index, InternalError, Result};
 
 pub struct GeoExtractor {
     grenad_parameters: GrenadParameters,
+    thread_count: usize,
 }
 
 impl GeoExtractor {
@@ -28,11 +29,12 @@ impl GeoExtractor {
         rtxn: &RoTxn,
         index: &Index,
         grenad_parameters: GrenadParameters,
+        thread_count: usize,
     ) -> Result<Option<Self>> {
         let is_sortable = index.sortable_fields(rtxn)?.contains(RESERVED_GEO_FIELD_NAME);
         let is_filterable = index.filterable_fields(rtxn)?.contains(RESERVED_GEO_FIELD_NAME);
         if is_sortable || is_filterable {
-            Ok(Some(GeoExtractor { grenad_parameters }))
+            Ok(Some(GeoExtractor { grenad_parameters, thread_count }))
         } else {
             Ok(None)
         }
@@ -157,7 +159,7 @@ impl<'extractor> Extractor<'extractor> for GeoExtractor {
     ) -> Result<()> {
         let rtxn = &context.rtxn;
         let index = context.index;
-        let max_memory = self.grenad_parameters.max_memory_by_thread();
+        let max_memory = self.grenad_parameters.max_memory_by_thread(self.thread_count);
         let db_fields_ids_map = context.db_fields_ids_map;
         let mut data_ref = context.data.borrow_mut_or_yield();
 

crates/milli/src/update/new/extract/mod.rs

@@ -5,7 +5,6 @@ mod geo;
 mod searchable;
 mod vectors;
 
-use bumpalo::Bump;
 pub use cache::{
     merge_caches_sorted, transpose_and_freeze_caches, BalancedCaches, DelAddRoaringBitmap,
 };
@@ -15,22 +14,6 @@ pub use geo::*;
 pub use searchable::*;
 pub use vectors::EmbeddingExtractor;
 
-use super::indexer::document_changes::{DocumentChanges, IndexingContext};
-use super::steps::IndexingStep;
-use super::thread_local::{FullySend, ThreadLocal};
-use crate::Result;
-
-pub trait DocidsExtractor {
-    fn run_extraction<'pl, 'fid, 'indexer, 'index, 'extractor, DC: DocumentChanges<'pl>, MSP>(
-        document_changes: &DC,
-        indexing_context: IndexingContext<'fid, 'indexer, 'index, MSP>,
-        extractor_allocs: &'extractor mut ThreadLocal<FullySend<Bump>>,
-        step: IndexingStep,
-    ) -> Result<Vec<BalancedCaches<'extractor>>>
-    where
-        MSP: Fn() -> bool + Sync;
-}
-
 /// TODO move in permissive json pointer
 pub mod perm_json_p {
     use serde_json::{Map, Value};

crates/milli/src/update/new/extract/searchable/extract_word_docids.rs

@@ -218,7 +218,7 @@ impl<'a, 'extractor> Extractor<'extractor> for WordDocidsExtractorData<'a> {
     fn init_data(&self, extractor_alloc: &'extractor Bump) -> Result<Self::Data> {
         Ok(RefCell::new(Some(WordDocidsBalancedCaches::new_in(
             self.buckets,
-            self.grenad_parameters.max_memory_by_thread(),
+            self.grenad_parameters.max_memory_by_thread(self.buckets),
             extractor_alloc,
         ))))
     }
@@ -240,6 +240,7 @@ pub struct WordDocidsExtractors;
 
 impl WordDocidsExtractors {
     pub fn run_extraction<'pl, 'fid, 'indexer, 'index, 'extractor, DC: DocumentChanges<'pl>, MSP>(
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
         document_changes: &DC,
         indexing_context: IndexingContext<'fid, 'indexer, 'index, MSP>,
         extractor_allocs: &'extractor mut ThreadLocal<FullySend<Bump>>,
@@ -288,10 +289,11 @@ impl WordDocidsExtractors {
             let extractor = WordDocidsExtractorData {
                 tokenizer: &document_tokenizer,
                 grenad_parameters: indexing_context.grenad_parameters,
-                buckets: rayon::current_num_threads(),
+                buckets: thread_pool.thread_count(),
             };
 
             extract(
+                thread_pool,
                 document_changes,
                 &extractor,
                 indexing_context,

crates/milli/src/update/new/extract/searchable/extract_word_pair_proximity_docids.rs

@@ -2,29 +2,62 @@ use std::cell::RefCell;
 use std::collections::VecDeque;
 use std::rc::Rc;
 
+use bumpalo::Bump;
 use heed::RoTxn;
 
-use super::tokenize_document::DocumentTokenizer;
+use super::tokenize_document::{tokenizer_builder, DocumentTokenizer};
-use super::SearchableExtractor;
 use crate::proximity::{index_proximity, MAX_DISTANCE};
 use crate::update::new::document::Document;
 use crate::update::new::extract::cache::BalancedCaches;
-use crate::update::new::indexer::document_changes::DocumentChangeContext;
+use crate::update::new::indexer::document_changes::{
+    extract, DocumentChangeContext, DocumentChanges, Extractor, IndexingContext,
+};
 use crate::update::new::ref_cell_ext::RefCellExt as _;
+use crate::update::new::steps::IndexingStep;
+use crate::update::new::thread_local::{FullySend, ThreadLocal};
 use crate::update::new::DocumentChange;
-use crate::{FieldId, GlobalFieldsIdsMap, Index, Result};
+use crate::update::GrenadParameters;
+use crate::{FieldId, GlobalFieldsIdsMap, Index, Result, MAX_POSITION_PER_ATTRIBUTE};
 
-pub struct WordPairProximityDocidsExtractor;
+impl<'a, 'extractor> Extractor<'extractor> for WordPairProximityDocidsExtractor<'a> {
+    type Data = RefCell<BalancedCaches<'extractor>>;
 
-impl SearchableExtractor for WordPairProximityDocidsExtractor {
+    fn init_data(&self, extractor_alloc: &'extractor Bump) -> Result<Self::Data> {
-    fn attributes_to_extract<'a>(
+        Ok(RefCell::new(BalancedCaches::new_in(
-        rtxn: &'a RoTxn,
+            self.buckets,
-        index: &'a Index,
+            self.grenad_parameters.max_memory_by_thread(self.buckets),
-    ) -> Result<Option<Vec<&'a str>>> {
+            extractor_alloc,
+        )))
+    }
+
+    fn process<'doc>(
+        &self,
+        changes: impl Iterator<Item = Result<DocumentChange<'doc>>>,
+        context: &DocumentChangeContext<Self::Data>,
+    ) -> Result<()> {
+        for change in changes {
+            let change = change?;
+            self.extract_document_change(context, change)?;
+        }
+        Ok(())
+    }
+}
+
+pub struct WordPairProximityDocidsExtractor<'a> {
+    tokenizer: &'a DocumentTokenizer<'a>,
+    grenad_parameters: &'a GrenadParameters,
+    buckets: usize,
+}
+
+impl<'a> WordPairProximityDocidsExtractor<'a> {
+    fn attributes_to_extract<'b>(
+        rtxn: &'b RoTxn,
+        index: &'b Index,
+    ) -> Result<Option<Vec<&'b str>>> {
         index.user_defined_searchable_fields(rtxn).map_err(Into::into)
     }
 
-    fn attributes_to_skip<'a>(_rtxn: &'a RoTxn, _index: &'a Index) -> Result<Vec<&'a str>> {
+    fn attributes_to_skip<'b>(_rtxn: &'b RoTxn, _index: &'b Index) -> Result<Vec<&'b str>> {
         Ok(Vec::new())
     }
 
@@ -32,10 +65,11 @@ impl SearchableExtractor for WordPairProximityDocidsExtractor {
     // and to store the docids of the documents that have a number of words in a given field
     // equal to or under than MAX_COUNTED_WORDS.
     fn extract_document_change(
+        &self,
         context: &DocumentChangeContext<RefCell<BalancedCaches>>,
-        document_tokenizer: &DocumentTokenizer,
         document_change: DocumentChange,
     ) -> Result<()> {
+        let document_tokenizer = self.tokenizer;
         let doc_alloc = &context.doc_alloc;
 
         let index = context.index;
@@ -129,6 +163,70 @@ impl SearchableExtractor for WordPairProximityDocidsExtractor {
         }
         Ok(())
     }
+
+    pub fn run_extraction<'pl, 'fid, 'indexer, 'index, 'extractor, DC: DocumentChanges<'pl>, MSP>(
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
+        document_changes: &DC,
+        indexing_context: IndexingContext<'fid, 'indexer, 'index, MSP>,
+        extractor_allocs: &'extractor mut ThreadLocal<FullySend<Bump>>,
+        step: IndexingStep,
+    ) -> Result<Vec<BalancedCaches<'extractor>>>
+    where
+        MSP: Fn() -> bool + Sync,
+    {
+        let rtxn = indexing_context.index.read_txn()?;
+        let stop_words = indexing_context.index.stop_words(&rtxn)?;
+        let allowed_separators = indexing_context.index.allowed_separators(&rtxn)?;
+        let allowed_separators: Option<Vec<_>> =
+            allowed_separators.as_ref().map(|s| s.iter().map(String::as_str).collect());
+        let dictionary = indexing_context.index.dictionary(&rtxn)?;
+        let dictionary: Option<Vec<_>> =
+            dictionary.as_ref().map(|s| s.iter().map(String::as_str).collect());
+        let mut builder = tokenizer_builder(
+            stop_words.as_ref(),
+            allowed_separators.as_deref(),
+            dictionary.as_deref(),
+        );
+        let tokenizer = builder.build();
+
+        let attributes_to_extract = Self::attributes_to_extract(&rtxn, indexing_context.index)?;
+        let attributes_to_skip = Self::attributes_to_skip(&rtxn, indexing_context.index)?;
+        let localized_attributes_rules =
+            indexing_context.index.localized_attributes_rules(&rtxn)?.unwrap_or_default();
+
+        let document_tokenizer = DocumentTokenizer {
+            tokenizer: &tokenizer,
+            attribute_to_extract: attributes_to_extract.as_deref(),
+            attribute_to_skip: attributes_to_skip.as_slice(),
+            localized_attributes_rules: &localized_attributes_rules,
+            max_positions_per_attributes: MAX_POSITION_PER_ATTRIBUTE,
+        };
+
+        let extractor_data: WordPairProximityDocidsExtractor = WordPairProximityDocidsExtractor {
+            tokenizer: &document_tokenizer,
+            grenad_parameters: indexing_context.grenad_parameters,
+            buckets: thread_pool.thread_count(),
+        };
+
+        let datastore = ThreadLocal::new();
+
+        {
+            let span =
+                tracing::trace_span!(target: "indexing::documents::extract", "docids_extraction");
+            let _entered = span.enter();
+            extract(
+                thread_pool,
+                document_changes,
+                &extractor_data,
+                indexing_context,
+                extractor_allocs,
+                &datastore,
+                step,
+            )?;
+        }
+
+        Ok(datastore.into_iter().map(RefCell::into_inner).collect())
+    }
 }
 
 fn build_key<'a>(

crates/milli/src/update/new/extract/searchable/mod.rs

@@ -1,146 +1,5 @@
 mod extract_word_docids;
 mod extract_word_pair_proximity_docids;
 mod tokenize_document;
-
-use std::cell::RefCell;
-use std::marker::PhantomData;
-
-use bumpalo::Bump;
 pub use extract_word_docids::{WordDocidsCaches, WordDocidsExtractors};
 pub use extract_word_pair_proximity_docids::WordPairProximityDocidsExtractor;
-use heed::RoTxn;
-use tokenize_document::{tokenizer_builder, DocumentTokenizer};
-
-use super::cache::BalancedCaches;
-use super::DocidsExtractor;
-use crate::update::new::indexer::document_changes::{
-    extract, DocumentChangeContext, DocumentChanges, Extractor, IndexingContext,
-};
-use crate::update::new::steps::IndexingStep;
-use crate::update::new::thread_local::{FullySend, ThreadLocal};
-use crate::update::new::DocumentChange;
-use crate::update::GrenadParameters;
-use crate::{Index, Result, MAX_POSITION_PER_ATTRIBUTE};
-
-pub struct SearchableExtractorData<'a, EX: SearchableExtractor> {
-    tokenizer: &'a DocumentTokenizer<'a>,
-    grenad_parameters: &'a GrenadParameters,
-    buckets: usize,
-    _ex: PhantomData<EX>,
-}
-
-impl<'a, 'extractor, EX: SearchableExtractor + Sync> Extractor<'extractor>
-    for SearchableExtractorData<'a, EX>
-{
-    type Data = RefCell<BalancedCaches<'extractor>>;
-
-    fn init_data(&self, extractor_alloc: &'extractor Bump) -> Result<Self::Data> {
-        Ok(RefCell::new(BalancedCaches::new_in(
-            self.buckets,
-            self.grenad_parameters.max_memory_by_thread(),
-            extractor_alloc,
-        )))
-    }
-
-    fn process<'doc>(
-        &self,
-        changes: impl Iterator<Item = Result<DocumentChange<'doc>>>,
-        context: &DocumentChangeContext<Self::Data>,
-    ) -> Result<()> {
-        for change in changes {
-            let change = change?;
-            EX::extract_document_change(context, self.tokenizer, change)?;
-        }
-        Ok(())
-    }
-}
-
-pub trait SearchableExtractor: Sized + Sync {
-    fn run_extraction<'pl, 'fid, 'indexer, 'index, 'extractor, DC: DocumentChanges<'pl>, MSP>(
-        document_changes: &DC,
-        indexing_context: IndexingContext<'fid, 'indexer, 'index, MSP>,
-        extractor_allocs: &'extractor mut ThreadLocal<FullySend<Bump>>,
-        step: IndexingStep,
-    ) -> Result<Vec<BalancedCaches<'extractor>>>
-    where
-        MSP: Fn() -> bool + Sync,
-    {
-        let rtxn = indexing_context.index.read_txn()?;
-        let stop_words = indexing_context.index.stop_words(&rtxn)?;
-        let allowed_separators = indexing_context.index.allowed_separators(&rtxn)?;
-        let allowed_separators: Option<Vec<_>> =
-            allowed_separators.as_ref().map(|s| s.iter().map(String::as_str).collect());
-        let dictionary = indexing_context.index.dictionary(&rtxn)?;
-        let dictionary: Option<Vec<_>> =
-            dictionary.as_ref().map(|s| s.iter().map(String::as_str).collect());
-        let mut builder = tokenizer_builder(
-            stop_words.as_ref(),
-            allowed_separators.as_deref(),
-            dictionary.as_deref(),
-        );
-        let tokenizer = builder.build();
-
-        let attributes_to_extract = Self::attributes_to_extract(&rtxn, indexing_context.index)?;
-        let attributes_to_skip = Self::attributes_to_skip(&rtxn, indexing_context.index)?;
-        let localized_attributes_rules =
-            indexing_context.index.localized_attributes_rules(&rtxn)?.unwrap_or_default();
-
-        let document_tokenizer = DocumentTokenizer {
-            tokenizer: &tokenizer,
-            attribute_to_extract: attributes_to_extract.as_deref(),
-            attribute_to_skip: attributes_to_skip.as_slice(),
-            localized_attributes_rules: &localized_attributes_rules,
-            max_positions_per_attributes: MAX_POSITION_PER_ATTRIBUTE,
-        };
-
-        let extractor_data: SearchableExtractorData<Self> = SearchableExtractorData {
-            tokenizer: &document_tokenizer,
-            grenad_parameters: indexing_context.grenad_parameters,
-            buckets: rayon::current_num_threads(),
-            _ex: PhantomData,
-        };
-
-        let datastore = ThreadLocal::new();
-
-        {
-            let span =
-                tracing::trace_span!(target: "indexing::documents::extract", "docids_extraction");
-            let _entered = span.enter();
-            extract(
-                document_changes,
-                &extractor_data,
-                indexing_context,
-                extractor_allocs,
-                &datastore,
-                step,
-            )?;
-        }
-
-        Ok(datastore.into_iter().map(RefCell::into_inner).collect())
-    }
-
-    fn extract_document_change(
-        context: &DocumentChangeContext<RefCell<BalancedCaches>>,
-        document_tokenizer: &DocumentTokenizer,
-        document_change: DocumentChange,
-    ) -> Result<()>;
-
-    fn attributes_to_extract<'a>(rtxn: &'a RoTxn, index: &'a Index)
-        -> Result<Option<Vec<&'a str>>>;
-
-    fn attributes_to_skip<'a>(rtxn: &'a RoTxn, index: &'a Index) -> Result<Vec<&'a str>>;
-}
-
-impl<T: SearchableExtractor> DocidsExtractor for T {
-    fn run_extraction<'pl, 'fid, 'indexer, 'index, 'extractor, DC: DocumentChanges<'pl>, MSP>(
-        document_changes: &DC,
-        indexing_context: IndexingContext<'fid, 'indexer, 'index, MSP>,
-        extractor_allocs: &'extractor mut ThreadLocal<FullySend<Bump>>,
-        step: IndexingStep,
-    ) -> Result<Vec<BalancedCaches<'extractor>>>
-    where
-        MSP: Fn() -> bool + Sync,
-    {
-        Self::run_extraction(document_changes, indexing_context, extractor_allocs, step)
-    }
-}

crates/milli/src/update/new/indexer/document_changes.rs

@@ -1,15 +1,14 @@
 use std::cell::{Cell, RefCell};
-use std::sync::atomic::Ordering;
+use std::marker::PhantomData;
+use std::sync::atomic::{AtomicU32, Ordering};
 use std::sync::{Arc, RwLock};
 
 use bumpalo::Bump;
 use heed::RoTxn;
-use rayon::iter::IndexedParallelIterator;
 
 use super::super::document_change::DocumentChange;
 use crate::fields_ids_map::metadata::FieldIdMapWithMetadata;
 use crate::progress::{AtomicDocumentStep, Progress};
-use crate::update::new::parallel_iterator_ext::ParallelIteratorExt as _;
 use crate::update::new::steps::IndexingStep;
 use crate::update::new::thread_local::{FullySend, MostlySend, ThreadLocal};
 use crate::update::GrenadParameters;
@@ -114,7 +113,7 @@ pub trait DocumentChanges<'pl // lifetime of the underlying payload
 >: Sync {
     type Item: Send;
 
-    fn iter(&self, chunk_size: usize) -> impl IndexedParallelIterator<Item = impl AsRef<[Self::Item]>>;
+    fn items(&self, thread_index: usize, task_index: usize) -> Option<&[Self::Item]>;
 
     fn len(&self) -> usize;
 
@@ -186,9 +185,10 @@ where
     }
 }
 
-const CHUNK_SIZE: usize = 100;
+pub const CHUNK_SIZE: usize = 100;
 
-pub fn extract<
+struct Extract<
+    'shared,    // covariant lifetime for shared borrows
     'pl,        // covariant lifetime of the underlying payload
     'extractor, // invariant lifetime of extractor_alloc
     'fid,       // invariant lifetime of fields ids map
@@ -196,31 +196,121 @@ pub fn extract<
     'data,      // invariant on EX::Data lifetime of datastore
     'index,     // covariant lifetime of the index
     EX,
+    DC,
+    MSP,
+> where
+    DC: DocumentChanges<'pl>,
+    EX: Extractor<'extractor>,
+    MSP: Fn() -> bool + Sync,
+{
+    document_changes: &'shared DC,
+    extractor: &'shared EX,
+    indexing_context: IndexingContext<'fid, 'indexer, 'index, MSP>,
+    extractor_allocs: &'extractor ThreadLocal<FullySend<Bump>>,
+    datastore: &'data ThreadLocal<EX::Data>,
+    step: Arc<AtomicU32>,
+    _marker: PhantomData<&'pl ()>,
+}
+
+impl<
+        'doc,
+        'extractor: 'doc, // invariant lifetime of extractor_alloc
+        'shared,
+        'pl,                     // covariant lifetime of the underlying payload
+        'fid: 'doc,              // invariant lifetime of fields ids map
+        'indexer: 'doc, // covariant lifetime of objects that are borrowed during the entire indexing
+        'data: 'doc,    // invariant on EX::Data lifetime of datastore
+        'index: 'doc + 'indexer, // covariant lifetime of the index
+        EX,
         DC: DocumentChanges<'pl>,
         MSP,
+    > scoped_thread_pool::Workload<'doc>
+    for Extract<'shared, 'pl, 'extractor, 'fid, 'indexer, 'data, 'index, EX, DC, MSP>
+where
+    EX: Extractor<'extractor>,
+    MSP: Fn() -> bool + Sync,
+{
+    type Context = DocumentChangeContext<'doc, 'extractor, 'fid, 'indexer, EX::Data>;
+
+    type Error = crate::Error;
+
+    fn context(
+        &self,
+        _thread_count: usize,
+        _thread_index: usize,
+    ) -> std::result::Result<
+        DocumentChangeContext<'doc, 'extractor, 'fid, 'indexer, EX::Data>,
+        Self::Error,
+    > {
+        let extractor = self.extractor;
+        DocumentChangeContext::new(
+            self.indexing_context.index,
+            self.indexing_context.db_fields_ids_map,
+            self.indexing_context.new_fields_ids_map,
+            self.extractor_allocs,
+            self.indexing_context.doc_allocs,
+            self.datastore,
+            self.indexing_context.fields_ids_map_store,
+            move |index_alloc| extractor.init_data(index_alloc),
+        )
+    }
+
+    fn run_task(
+        &self,
+        _thread_count: usize,
+        thread_index: usize,
+        task_index: usize,
+        context: &mut Self::Context,
+    ) -> Option<std::result::Result<(), Self::Error>> {
+        let items = self.document_changes.items(thread_index, task_index)?;
+        if (self.indexing_context.must_stop_processing)() {
+            return Some(Err(InternalError::AbortedIndexation.into()));
+        }
+
+        // Clean up and reuse the document-specific allocator
+        context.doc_alloc.reset();
+
+        let changes = items.iter().filter_map(|item| {
+            self.document_changes.item_to_document_change(context, item).transpose()
+        });
+
+        let res = self.extractor.process(changes, context);
+        self.step.fetch_add(items.as_ref().len() as u32, Ordering::Relaxed);
+
+        // send back the doc_alloc in the pool
+        context.doc_allocs.get_or_default().0.set(std::mem::take(&mut context.doc_alloc));
+
+        Some(res)
+    }
+}
+
+pub fn extract<
+    'pool,      // invariant lifetime of the thread pool
+    'pl,        // covariant lifetime of the underlying payload
+    'extractor, // invariant lifetime of extractor_alloc
+    'fid,       // invariant lifetime of fields ids map
+    'indexer,   // covariant lifetime of objects that are borrowed during the entire indexing
+    'data,      // invariant on EX::Data lifetime of datastore
+    'index,     // covariant lifetime of the index
+    EX,
+    DC,
+    MSP,
 >(
+    thread_pool: &'pool scoped_thread_pool::ThreadPool<crate::Error>,
     document_changes: &DC,
     extractor: &EX,
-    IndexingContext {
+    indexing_context: IndexingContext<'fid, 'indexer, 'index, MSP>,
-        index,
-        db_fields_ids_map,
-        new_fields_ids_map,
-        doc_allocs,
-        fields_ids_map_store,
-        must_stop_processing,
-        progress,
-        grenad_parameters: _,
-    }: IndexingContext<'fid, 'indexer, 'index, MSP>,
     extractor_allocs: &'extractor mut ThreadLocal<FullySend<Bump>>,
     datastore: &'data ThreadLocal<EX::Data>,
     step: IndexingStep,
 ) -> Result<()>
 where
+    DC: DocumentChanges<'pl>,
     EX: Extractor<'extractor>,
     MSP: Fn() -> bool + Sync,
 {
     tracing::trace!("We are resetting the extractor allocators");
-    progress.update_progress(step);
+    indexing_context.progress.update_progress(step);
     // Clean up and reuse the extractor allocs
     for extractor_alloc in extractor_allocs.iter_mut() {
         tracing::trace!("\tWith {} bytes reset", extractor_alloc.0.allocated_bytes());
@@ -229,45 +319,22 @@ where
 
     let total_documents = document_changes.len() as u32;
     let (step, progress_step) = AtomicDocumentStep::new(total_documents);
-    progress.update_progress(progress_step);
+    indexing_context.progress.update_progress(progress_step);
 
-    let pi = document_changes.iter(CHUNK_SIZE);
+    let extract = Extract {
-    pi.try_arc_for_each_try_init(
+        document_changes,
-        || {
+        extractor,
-            DocumentChangeContext::new(
+        indexing_context,
-                index,
-                db_fields_ids_map,
-                new_fields_ids_map,
         extractor_allocs,
-                doc_allocs,
         datastore,
-                fields_ids_map_store,
+        step,
-                move |index_alloc| extractor.init_data(index_alloc),
+        _marker: PhantomData,
-            )
+    };
-        },
+    thread_pool
-        |context, items| {
+        .execute(&extract)
-            if (must_stop_processing)() {
+        .map_err(|errors| crate::Error::from_scoped_thread_pool_errors(thread_pool, errors))?;
-                return Err(Arc::new(InternalError::AbortedIndexation.into()));
-            }
 
-            // Clean up and reuse the document-specific allocator
+    extract.step.store(total_documents, Ordering::Relaxed);
-            context.doc_alloc.reset();
-
-            let items = items.as_ref();
-            let changes = items.iter().filter_map(|item| {
-                document_changes.item_to_document_change(context, item).transpose()
-            });
-
-            let res = extractor.process(changes, context).map_err(Arc::new);
-            step.fetch_add(items.as_ref().len() as u32, Ordering::Relaxed);
-
-            // send back the doc_alloc in the pool
-            context.doc_allocs.get_or_default().0.set(std::mem::take(&mut context.doc_alloc));
-
-            res
-        },
-    )?;
-    step.store(total_documents, Ordering::Relaxed);
 
     Ok(())
 }

crates/milli/src/update/new/indexer/document_deletion.rs

@@ -1,8 +1,7 @@
 use bumpalo::collections::CollectIn;
 use bumpalo::Bump;
-use rayon::iter::IndexedParallelIterator;
-use rayon::slice::ParallelSlice as _;
 use roaring::RoaringBitmap;
+use scoped_thread_pool::PartitionChunks;
 
 use super::document_changes::{DocumentChangeContext, DocumentChanges};
 use crate::documents::PrimaryKey;
@@ -28,31 +27,28 @@ impl DocumentDeletion {
         self,
         indexer_alloc: &'indexer Bump,
         primary_key: PrimaryKey<'indexer>,
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
+        chunk_size: usize,
     ) -> DocumentDeletionChanges<'indexer> {
         let to_delete: bumpalo::collections::Vec<_> =
             self.to_delete.into_iter().collect_in(indexer_alloc);
 
         let to_delete = to_delete.into_bump_slice();
 
+        let to_delete = PartitionChunks::new(to_delete, chunk_size, thread_pool.thread_count());
+
         DocumentDeletionChanges { to_delete, primary_key }
     }
 }
 
 pub struct DocumentDeletionChanges<'indexer> {
-    to_delete: &'indexer [DocumentId],
+    to_delete: scoped_thread_pool::PartitionChunks<'indexer, DocumentId>,
     primary_key: PrimaryKey<'indexer>,
 }
 
 impl<'pl> DocumentChanges<'pl> for DocumentDeletionChanges<'pl> {
     type Item = DocumentId;
 
-    fn iter(
-        &self,
-        chunk_size: usize,
-    ) -> impl IndexedParallelIterator<Item = impl AsRef<[Self::Item]>> {
-        self.to_delete.par_chunks(chunk_size)
-    }
-
     fn item_to_document_change<
         'doc, // lifetime of a single `process` call
         T: MostlySend,
@@ -78,7 +74,11 @@ impl<'pl> DocumentChanges<'pl> for DocumentDeletionChanges<'pl> {
     }
 
     fn len(&self) -> usize {
-        self.to_delete.len()
+        self.to_delete.slice().len()
+    }
+
+    fn items(&self, thread_index: usize, task_index: usize) -> Option<&[Self::Item]> {
+        self.to_delete.partition(thread_index, task_index)
     }
 }
 
@@ -86,6 +86,7 @@ impl<'pl> DocumentChanges<'pl> for DocumentDeletionChanges<'pl> {
 mod test {
     use std::cell::RefCell;
     use std::marker::PhantomData;
+    use std::num::NonZeroUsize;
     use std::sync::RwLock;
 
     use bumpalo::Bump;
@@ -94,7 +95,7 @@ mod test {
     use crate::index::tests::TempIndex;
     use crate::progress::Progress;
     use crate::update::new::indexer::document_changes::{
-        extract, DocumentChangeContext, Extractor, IndexingContext,
+        extract, DocumentChangeContext, Extractor, IndexingContext, CHUNK_SIZE,
     };
     use crate::update::new::indexer::DocumentDeletion;
     use crate::update::new::steps::IndexingStep;
@@ -135,6 +136,9 @@ mod test {
             }
         }
 
+        let thread_pool =
+            scoped_thread_pool::ThreadPool::new(NonZeroUsize::new(1).unwrap(), "test".into());
+
         let mut deletions = DocumentDeletion::new();
         deletions.delete_documents_by_docids(Vec::<u32>::new().into_iter().collect());
         let indexer = Bump::new();
@@ -155,8 +159,12 @@ mod test {
 
         let deletion_tracker = TrackDeletion(PhantomData);
 
-        let changes = deletions
+        let changes = deletions.into_changes(
-            .into_changes(&indexer, crate::documents::PrimaryKey::Flat { name: "id", field_id: 0 });
+            &indexer,
+            crate::documents::PrimaryKey::Flat { name: "id", field_id: 0 },
+            &thread_pool,
+            CHUNK_SIZE,
+        );
 
         let context = IndexingContext {
             index: &index,
@@ -173,6 +181,7 @@ mod test {
             let datastore = ThreadLocal::new();
 
             extract(
+                &thread_pool,
                 &changes,
                 &deletion_tracker,
                 context,

crates/milli/src/update/new/indexer/document_operation.rs

@@ -6,8 +6,8 @@ use bumparaw_collections::RawMap;
 use hashbrown::hash_map::Entry;
 use heed::RoTxn;
 use memmap2::Mmap;
-use rayon::slice::ParallelSlice;
 use rustc_hash::FxBuildHasher;
+use scoped_thread_pool::PartitionChunks;
 use serde_json::value::RawValue;
 use serde_json::Deserializer;
 
@@ -57,6 +57,8 @@ impl<'pl> DocumentOperation<'pl> {
         new_fields_ids_map: &mut FieldsIdsMap,
         must_stop_processing: &MSP,
         progress: Progress,
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
+        chunk_size: usize,
     ) -> Result<(DocumentOperationChanges<'pl>, Vec<PayloadStats>, Option<PrimaryKey<'pl>>)>
     where
         MSP: Fn() -> bool,
@@ -130,6 +132,8 @@ impl<'pl> DocumentOperation<'pl> {
         docids_version_offsets.sort_unstable_by_key(|(_, po)| method.sort_key(&po.operations));
 
         let docids_version_offsets = docids_version_offsets.into_bump_slice();
+        let docids_version_offsets =
+            PartitionChunks::new(docids_version_offsets, chunk_size, thread_pool.thread_count());
         Ok((DocumentOperationChanges { docids_version_offsets }, operations_stats, primary_key))
     }
 }
@@ -353,13 +357,6 @@ fn merge_version_offsets<'s, 'pl>(
 impl<'pl> DocumentChanges<'pl> for DocumentOperationChanges<'pl> {
     type Item = (&'pl str, PayloadOperations<'pl>);
 
-    fn iter(
-        &self,
-        chunk_size: usize,
-    ) -> impl rayon::prelude::IndexedParallelIterator<Item = impl AsRef<[Self::Item]>> {
-        self.docids_version_offsets.par_chunks(chunk_size)
-    }
-
     fn item_to_document_change<'doc, T: MostlySend + 'doc>(
         &'doc self,
         context: &'doc DocumentChangeContext<T>,
@@ -379,12 +376,16 @@ impl<'pl> DocumentChanges<'pl> for DocumentOperationChanges<'pl> {
     }
 
     fn len(&self) -> usize {
-        self.docids_version_offsets.len()
+        self.docids_version_offsets.slice().len()
+    }
+
+    fn items(&self, thread_index: usize, task_index: usize) -> Option<&[Self::Item]> {
+        self.docids_version_offsets.partition(thread_index, task_index)
     }
 }
 
 pub struct DocumentOperationChanges<'pl> {
-    docids_version_offsets: &'pl [(&'pl str, PayloadOperations<'pl>)],
+    docids_version_offsets: PartitionChunks<'pl, (&'pl str, PayloadOperations<'pl>)>,
 }
 
 pub enum Payload<'pl> {

crates/milli/src/update/new/indexer/extract.rs

@@ -22,6 +22,7 @@ use crate::{Result, ThreadPoolNoAbort, ThreadPoolNoAbortBuilder};
 
 #[allow(clippy::too_many_arguments)]
 pub(super) fn extract_all<'pl, 'extractor, DC, MSP>(
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
     document_changes: &DC,
     indexing_context: IndexingContext<MSP>,
     indexer_span: Span,
@@ -47,11 +48,12 @@ where
     // document but we need to create a function that collects and compresses documents.
     let document_sender = extractor_sender.documents();
     let document_extractor = DocumentsExtractor::new(document_sender, embedders);
-    let datastore = ThreadLocal::with_capacity(rayon::current_num_threads());
+    let datastore = ThreadLocal::with_capacity(thread_pool.thread_count());
     {
         let span = tracing::trace_span!(target: "indexing::documents::extract", parent: &indexer_span, "documents");
         let _entered = span.enter();
         extract(
+            thread_pool,
             document_changes,
             &document_extractor,
             indexing_context,
@@ -84,6 +86,7 @@ where
             let _entered = span.enter();
 
             FacetedDocidsExtractor::run_extraction(
+                thread_pool,
                 document_changes,
                 indexing_context,
                 extractor_allocs,
@@ -97,6 +100,7 @@ where
             let _entered = span.enter();
 
             facet_field_ids_delta = merge_and_send_facet_docids(
+                thread_pool,
                 caches,
                 FacetDatabases::new(index),
                 index,
@@ -118,6 +122,7 @@ where
             let _entered = span.enter();
 
             WordDocidsExtractors::run_extraction(
+                thread_pool,
                 document_changes,
                 indexing_context,
                 extractor_allocs,
@@ -129,6 +134,7 @@ where
             let span = tracing::trace_span!(target: "indexing::documents::merge", "word_docids");
             let _entered = span.enter();
             merge_and_send_docids(
+                thread_pool,
                 word_docids,
                 index.word_docids.remap_types(),
                 index,
@@ -142,6 +148,7 @@ where
                 tracing::trace_span!(target: "indexing::documents::merge", "word_fid_docids");
             let _entered = span.enter();
             merge_and_send_docids(
+                thread_pool,
                 word_fid_docids,
                 index.word_fid_docids.remap_types(),
                 index,
@@ -155,6 +162,7 @@ where
                 tracing::trace_span!(target: "indexing::documents::merge", "exact_word_docids");
             let _entered = span.enter();
             merge_and_send_docids(
+                thread_pool,
                 exact_word_docids,
                 index.exact_word_docids.remap_types(),
                 index,
@@ -168,6 +176,7 @@ where
                 tracing::trace_span!(target: "indexing::documents::merge", "word_position_docids");
             let _entered = span.enter();
             merge_and_send_docids(
+                thread_pool,
                 word_position_docids,
                 index.word_position_docids.remap_types(),
                 index,
@@ -181,6 +190,7 @@ where
                 tracing::trace_span!(target: "indexing::documents::merge", "fid_word_count_docids");
             let _entered = span.enter();
             merge_and_send_docids(
+                thread_pool,
                 fid_word_count_docids,
                 index.field_id_word_count_docids.remap_types(),
                 index,
@@ -198,7 +208,8 @@ where
             let span = tracing::trace_span!(target: "indexing::documents::extract", "word_pair_proximity_docids");
             let _entered = span.enter();
 
-            <WordPairProximityDocidsExtractor as DocidsExtractor>::run_extraction(
+            WordPairProximityDocidsExtractor::run_extraction(
+                thread_pool,
                 document_changes,
                 indexing_context,
                 extractor_allocs,
@@ -211,6 +222,7 @@ where
             let _entered = span.enter();
 
             merge_and_send_docids(
+                thread_pool,
                 caches,
                 index.word_pair_proximity_docids.remap_types(),
                 index,
@@ -232,12 +244,13 @@ where
             field_distribution,
             request_threads(),
         );
-        let mut datastore = ThreadLocal::with_capacity(rayon::current_num_threads());
+        let mut datastore = ThreadLocal::with_capacity(thread_pool.thread_count());
         {
             let span = tracing::debug_span!(target: "indexing::documents::extract", "vectors");
             let _entered = span.enter();
 
             extract(
+                thread_pool,
                 document_changes,
                 &extractor,
                 indexing_context,
@@ -263,17 +276,23 @@ where
     }
 
     'geo: {
-        let Some(extractor) = GeoExtractor::new(&rtxn, index, *indexing_context.grenad_parameters)?
+        let Some(extractor) = GeoExtractor::new(
+            &rtxn,
+            index,
+            *indexing_context.grenad_parameters,
+            thread_pool.thread_count(),
+        )?
         else {
             break 'geo;
         };
-        let datastore = ThreadLocal::with_capacity(rayon::current_num_threads());
+        let datastore = ThreadLocal::with_capacity(thread_pool.thread_count());
 
         {
             let span = tracing::trace_span!(target: "indexing::documents::extract", "geo");
             let _entered = span.enter();
 
             extract(
+                thread_pool,
                 document_changes,
                 &extractor,
                 indexing_context,
@@ -289,6 +308,7 @@ where
             index,
             extractor_sender.geo(),
             &indexing_context.must_stop_processing,
+            thread_pool,
         )?;
     }
     indexing_context.progress.update_progress(IndexingStep::WritingToDatabase);

crates/milli/src/update/new/indexer/mod.rs

@@ -44,6 +44,7 @@ static LOG_MEMORY_METRICS_ONCE: Once = Once::new();
 pub fn index<'pl, 'indexer, 'index, DC, MSP>(
     wtxn: &mut RwTxn,
     index: &'index Index,
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
     pool: &ThreadPoolNoAbort,
     grenad_parameters: GrenadParameters,
     db_fields_ids_map: &'indexer FieldsIdsMap,
@@ -104,16 +105,15 @@ where
         );
     });
 
-    let (extractor_sender, writer_receiver) = pool
+    let (extractor_sender, writer_receiver) =
-        .install(|| extractor_writer_bbqueue(&mut bbbuffers, total_bbbuffer_capacity, 1000))
+        extractor_writer_bbqueue(thread_pool, &mut bbbuffers, total_bbbuffer_capacity, 1000);
-        .unwrap();
 
     let metadata_builder = MetadataBuilder::from_index(index, wtxn)?;
     let new_fields_ids_map = FieldIdMapWithMetadata::new(new_fields_ids_map, metadata_builder);
     let new_fields_ids_map = RwLock::new(new_fields_ids_map);
-    let fields_ids_map_store = ThreadLocal::with_capacity(rayon::current_num_threads());
+    let fields_ids_map_store = ThreadLocal::with_capacity(thread_pool.thread_count());
-    let mut extractor_allocs = ThreadLocal::with_capacity(rayon::current_num_threads());
+    let mut extractor_allocs = ThreadLocal::with_capacity(thread_pool.thread_count());
-    let doc_allocs = ThreadLocal::with_capacity(rayon::current_num_threads());
+    let doc_allocs = ThreadLocal::with_capacity(thread_pool.thread_count());
 
     let indexing_context = IndexingContext {
         index,
@@ -139,8 +139,8 @@ where
         let document_ids = &mut document_ids;
         let extractor_handle =
             Builder::new().name(S("indexer-extractors")).spawn_scoped(s, move || {
-                pool.install(move || {
                 extract::extract_all(
+                    thread_pool,
                     document_changes,
                     indexing_context,
                     indexer_span,
@@ -152,8 +152,6 @@ where
                     index_embeddings,
                     document_ids,
                 )
-                })
-                .unwrap()
             })?;
 
         let global_fields_ids_map = GlobalFieldsIdsMap::new(&new_fields_ids_map);
@@ -206,6 +204,7 @@ where
             wtxn,
             global_fields_ids_map,
             facet_field_ids_delta,
+            thread_pool,
         )?;
 
         indexing_context.progress.update_progress(IndexingStep::Finalizing);

crates/milli/src/update/new/indexer/partial_dump.rs

@@ -1,8 +1,8 @@
 use std::ops::DerefMut;
 
 use bumparaw_collections::RawMap;
-use rayon::iter::IndexedParallelIterator;
 use rustc_hash::FxBuildHasher;
+use scoped_thread_pool::ThreadPool;
 use serde_json::value::RawValue;
 
 use super::document_changes::{DocumentChangeContext, DocumentChanges};
@@ -14,45 +14,34 @@ use crate::update::new::thread_local::MostlySend;
 use crate::update::new::{DocumentChange, Insertion};
 use crate::{Error, InternalError, Result, UserError};
 
-pub struct PartialDump<I> {
+pub struct PartialDump;
-    iter: I,
-}
 
-impl<I> PartialDump<I> {
+impl PartialDump {
-    pub fn new_from_jsonlines(iter: I) -> Self {
+    pub fn new_from_jsonlines() -> Self {
-        PartialDump { iter }
+        PartialDump
     }
 
     pub fn into_changes<'index>(
         self,
         concurrent_available_ids: &'index ConcurrentAvailableIds,
         primary_key: &'index PrimaryKey,
-    ) -> PartialDumpChanges<'index, I> {
+        _thread_pool: &ThreadPool<crate::Error>,
+        _chunk_size: usize,
+    ) -> PartialDumpChanges<'index> {
         // Note for future self:
         //   - We recommend sending chunks of documents in this `PartialDumpIndexer` we therefore need to create a custom take_while_size method (that doesn't drop items).
-        PartialDumpChanges { iter: self.iter, concurrent_available_ids, primary_key }
+        PartialDumpChanges { concurrent_available_ids, primary_key }
     }
 }
 
-pub struct PartialDumpChanges<'doc, I> {
+pub struct PartialDumpChanges<'doc> {
-    iter: I,
     concurrent_available_ids: &'doc ConcurrentAvailableIds,
     primary_key: &'doc PrimaryKey<'doc>,
 }
 
-impl<'index, Iter> DocumentChanges<'index> for PartialDumpChanges<'index, Iter>
+impl<'index> DocumentChanges<'index> for PartialDumpChanges<'index> {
-where
-    Iter: IndexedParallelIterator<Item = Box<RawValue>> + Clone + Sync + 'index,
-{
     type Item = Box<RawValue>;
 
-    fn iter(
-        &self,
-        chunk_size: usize,
-    ) -> impl IndexedParallelIterator<Item = impl AsRef<[Self::Item]>> {
-        self.iter.clone().chunks(chunk_size)
-    }
-
     fn item_to_document_change<'doc, T: MostlySend + 'doc>(
         &'doc self,
         context: &'doc DocumentChangeContext<T>,
@@ -85,6 +74,10 @@ where
     }
 
     fn len(&self) -> usize {
-        self.iter.len()
+        unimplemented!()
+    }
+
+    fn items(&self, thread_index: usize, task_index: usize) -> Option<&[Self::Item]> {
+        unimplemented!()
     }
 }

crates/milli/src/update/new/indexer/post_processing.rs

@@ -27,6 +27,7 @@ pub(super) fn post_process<MSP>(
     wtxn: &mut RwTxn<'_>,
     global_fields_ids_map: GlobalFieldsIdsMap<'_>,
     facet_field_ids_delta: FacetFieldIdsDelta,
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
 ) -> Result<()>
 where
     MSP: Fn() -> bool + Sync,
@@ -39,7 +40,13 @@ where
     compute_facet_level_database(index, wtxn, facet_field_ids_delta)?;
     indexing_context.progress.update_progress(IndexingStep::PostProcessingWords);
     if let Some(prefix_delta) = compute_word_fst(index, wtxn)? {
-        compute_prefix_database(index, wtxn, prefix_delta, indexing_context.grenad_parameters)?;
+        compute_prefix_database(
+            index,
+            wtxn,
+            prefix_delta,
+            indexing_context.grenad_parameters,
+            thread_pool,
+        )?;
     };
     Ok(())
 }
@@ -50,16 +57,38 @@ fn compute_prefix_database(
     wtxn: &mut RwTxn,
     prefix_delta: PrefixDelta,
     grenad_parameters: &GrenadParameters,
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
 ) -> Result<()> {
     let PrefixDelta { modified, deleted } = prefix_delta;
     // Compute word prefix docids
-    compute_word_prefix_docids(wtxn, index, &modified, &deleted, grenad_parameters)?;
+    compute_word_prefix_docids(wtxn, index, &modified, &deleted, grenad_parameters, thread_pool)?;
     // Compute exact word prefix docids
-    compute_exact_word_prefix_docids(wtxn, index, &modified, &deleted, grenad_parameters)?;
+    compute_exact_word_prefix_docids(
+        wtxn,
+        index,
+        &modified,
+        &deleted,
+        grenad_parameters,
+        thread_pool,
+    )?;
     // Compute word prefix fid docids
-    compute_word_prefix_fid_docids(wtxn, index, &modified, &deleted, grenad_parameters)?;
+    compute_word_prefix_fid_docids(
+        wtxn,
+        index,
+        &modified,
+        &deleted,
+        grenad_parameters,
+        thread_pool,
+    )?;
     // Compute word prefix position docids
-    compute_word_prefix_position_docids(wtxn, index, &modified, &deleted, grenad_parameters)
+    compute_word_prefix_position_docids(
+        wtxn,
+        index,
+        &modified,
+        &deleted,
+        grenad_parameters,
+        thread_pool,
+    )
 }
 
 #[tracing::instrument(level = "trace", skip_all, target = "indexing")]

crates/milli/src/update/new/indexer/update_by_function.rs

@@ -1,9 +1,10 @@
+use bumpalo::collections::CollectIn;
+use bumpalo::Bump;
 use bumparaw_collections::RawMap;
-use rayon::iter::IndexedParallelIterator;
-use rayon::slice::ParallelSlice as _;
 use rhai::{Dynamic, Engine, OptimizationLevel, Scope, AST};
 use roaring::RoaringBitmap;
 use rustc_hash::FxBuildHasher;
+use scoped_thread_pool::{PartitionChunks, ThreadPool};
 
 use super::document_changes::DocumentChangeContext;
 use super::DocumentChanges;
@@ -22,14 +23,12 @@ pub struct UpdateByFunction {
     code: String,
 }
 
-pub struct UpdateByFunctionChanges<'doc> {
+pub struct UpdateByFunctionChanges<'index> {
-    primary_key: &'doc PrimaryKey<'doc>,
+    primary_key: &'index PrimaryKey<'index>,
     engine: Engine,
     ast: AST,
     context: Option<Dynamic>,
-    // It is sad that the RoaringBitmap doesn't
+    documents: PartitionChunks<'index, u32>,
-    // implement IndexedParallelIterator
-    documents: Vec<u32>,
 }
 
 impl UpdateByFunction {
@@ -40,6 +39,9 @@ impl UpdateByFunction {
     pub fn into_changes<'index>(
         self,
         primary_key: &'index PrimaryKey,
+        allocator: &'index Bump,
+        thread_pool: &ThreadPool<crate::Error>,
+        chunk_size: usize,
     ) -> Result<UpdateByFunctionChanges<'index>> {
         let Self { documents, context, code } = self;
 
@@ -64,26 +66,19 @@ impl UpdateByFunction {
             None => None,
         };
 
-        Ok(UpdateByFunctionChanges {
+        let documents: bumpalo::collections::Vec<'_, _> =
-            primary_key,
+            documents.into_iter().collect_in(allocator);
-            engine,
+        let documents = documents.into_bump_slice();
-            ast,
+
-            context,
+        let documents = PartitionChunks::new(documents, chunk_size, thread_pool.thread_count());
-            documents: documents.into_iter().collect(),
+
-        })
+        Ok(UpdateByFunctionChanges { primary_key, engine, ast, context, documents })
     }
 }
 
 impl<'index> DocumentChanges<'index> for UpdateByFunctionChanges<'index> {
     type Item = u32;
 
-    fn iter(
-        &self,
-        chunk_size: usize,
-    ) -> impl IndexedParallelIterator<Item = impl AsRef<[Self::Item]>> {
-        self.documents.as_slice().par_chunks(chunk_size)
-    }
-
     fn item_to_document_change<'doc, T: MostlySend + 'doc>(
         &self,
         context: &'doc DocumentChangeContext<T>,
@@ -185,7 +180,11 @@ impl<'index> DocumentChanges<'index> for UpdateByFunctionChanges<'index> {
     }
 
     fn len(&self) -> usize {
-        self.documents.len()
+        self.documents.slice().len()
+    }
+
+    fn items(&self, thread_index: usize, task_index: usize) -> Option<&[Self::Item]> {
+        self.documents.partition(thread_index, task_index)
     }
 }
 

crates/milli/src/update/new/merger.rs

@@ -1,10 +1,10 @@
 use std::cell::RefCell;
+use std::sync::Mutex;
 
 use hashbrown::HashMap;
 use heed::types::Bytes;
 use heed::{Database, RoTxn};
 use memmap2::Mmap;
-use rayon::iter::{IntoParallelIterator, ParallelIterator};
 use roaring::RoaringBitmap;
 
 use super::channel::*;
@@ -22,6 +22,7 @@ pub fn merge_and_send_rtree<'extractor, MSP>(
     index: &Index,
     geo_sender: GeoSender<'_, '_>,
     must_stop_processing: &MSP,
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
 ) -> Result<()>
 where
     MSP: Fn() -> bool + Sync,
@@ -57,13 +58,14 @@ where
 
     let rtree_mmap = unsafe { Mmap::map(&file)? };
     geo_sender.set_rtree(rtree_mmap).unwrap();
-    geo_sender.set_geo_faceted(&faceted)?;
+    geo_sender.set_geo_faceted(&faceted, thread_pool)?;
 
     Ok(())
 }
 
 #[tracing::instrument(level = "trace", skip_all, target = "indexing::merge")]
 pub fn merge_and_send_docids<'extractor, MSP, D>(
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
     mut caches: Vec<BalancedCaches<'extractor>>,
     database: Database<Bytes, Bytes>,
     index: &Index,
@@ -74,7 +76,10 @@ where
     MSP: Fn() -> bool + Sync,
     D: DatabaseType + Sync,
 {
-    transpose_and_freeze_caches(&mut caches)?.into_par_iter().try_for_each(|frozen| {
+    let frozen_caches = Mutex::new(transpose_and_freeze_caches(&mut caches)?);
+
+    match thread_pool.broadcast(|thread_index| {
+        let frozen = std::mem::take(frozen_caches.lock().unwrap().get_mut(thread_index).unwrap());
         let rtxn = index.read_txn()?;
         if must_stop_processing() {
             return Err(InternalError::AbortedIndexation.into());
@@ -92,12 +97,17 @@ where
                 }
                 Operation::Ignore => Ok(()),
             }
-        })
+        })?;
-    })
+        Ok(())
+    }) {
+        Ok(()) => Ok(()),
+        Err(errors) => Err(crate::Error::from_scoped_thread_pool_errors(thread_pool, errors)),
+    }
 }
 
 #[tracing::instrument(level = "trace", skip_all, target = "indexing::merge")]
 pub fn merge_and_send_facet_docids<'extractor>(
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
     mut caches: Vec<BalancedCaches<'extractor>>,
     database: FacetDatabases,
     index: &Index,
@@ -108,9 +118,15 @@ pub fn merge_and_send_facet_docids<'extractor>(
     let max_number_count = (index.facet_id_f64_docids.len(rtxn)? / 500) as usize;
     let max_string_count = max_string_count.clamp(1000, 100_000);
     let max_number_count = max_number_count.clamp(1000, 100_000);
-    transpose_and_freeze_caches(&mut caches)?
+    let transposed_frozen_caches = Mutex::new(transpose_and_freeze_caches(&mut caches)?);
-        .into_par_iter()
+    let output = Mutex::new(FacetFieldIdsDelta::new(max_string_count, max_number_count));
-        .map(|frozen| {
+    thread_pool
+        .broadcast(|thread_index| {
+            // TODO: we can probably spare the mutex here since it is guaranteed that each thread will access its own cell of the vec
+            let frozen = std::mem::take(
+                transposed_frozen_caches.lock().unwrap().get_mut(thread_index).unwrap(),
+            );
+
             let mut facet_field_ids_delta =
                 FacetFieldIdsDelta::new(max_string_count, max_number_count);
             let rtxn = index.read_txn()?;
@@ -130,13 +146,18 @@ pub fn merge_and_send_facet_docids<'extractor>(
                     Operation::Ignore => Ok(()),
                 }
             })?;
-
+            {
-            Ok(facet_field_ids_delta)
+                let mut common = output.lock().unwrap();
-        })
+                *common = std::mem::replace(
-        .reduce(
+                    &mut *common,
-            || Ok(FacetFieldIdsDelta::new(max_string_count, max_number_count)),
+                    FacetFieldIdsDelta::new(max_string_count, max_number_count),
-            |lhs, rhs| Ok(lhs?.merge(rhs?)),
                 )
+                .merge(facet_field_ids_delta);
+            }
+            Ok(())
+        })
+        .map_err(|errors| crate::Error::from_scoped_thread_pool_errors(thread_pool, errors))?;
+    Ok(output.into_inner().unwrap())
 }
 
 pub struct FacetDatabases<'a> {

crates/milli/src/update/new/words_prefix_docids.rs

@@ -26,11 +26,13 @@ impl WordPrefixDocids {
         database: Database<Bytes, CboRoaringBitmapCodec>,
         prefix_database: Database<Bytes, CboRoaringBitmapCodec>,
         grenad_parameters: &GrenadParameters,
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
     ) -> WordPrefixDocids {
         WordPrefixDocids {
             database,
             prefix_database,
-            max_memory_by_thread: grenad_parameters.max_memory_by_thread(),
+            max_memory_by_thread: grenad_parameters
+                .max_memory_by_thread(thread_pool.thread_count()),
         }
     }
 
@@ -39,9 +41,10 @@ impl WordPrefixDocids {
         wtxn: &mut heed::RwTxn,
         prefix_to_compute: &BTreeSet<Prefix>,
         prefix_to_delete: &BTreeSet<Prefix>,
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
     ) -> Result<()> {
         delete_prefixes(wtxn, &self.prefix_database, prefix_to_delete)?;
-        self.recompute_modified_prefixes(wtxn, prefix_to_compute)
+        self.recompute_modified_prefixes(wtxn, prefix_to_compute, thread_pool)
     }
 
     #[tracing::instrument(level = "trace", skip_all, target = "indexing::prefix")]
@@ -49,6 +52,7 @@ impl WordPrefixDocids {
         &self,
         wtxn: &mut RwTxn,
         prefixes: &BTreeSet<Prefix>,
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
     ) -> Result<()> {
         // We fetch the docids associated to the newly added word prefix fst only.
         // And collect the CboRoaringBitmaps pointers in an HashMap.
@@ -56,7 +60,7 @@ impl WordPrefixDocids {
 
         // We access this HashMap in parallel to compute the *union* of all
         // of them and *serialize* them into files. There is one file by CPU.
-        let local_entries = ThreadLocal::with_capacity(rayon::current_num_threads());
+        let local_entries = ThreadLocal::with_capacity(thread_pool.thread_count());
         prefixes.into_par_iter().map(AsRef::as_ref).try_for_each(|prefix| {
             let refcell = local_entries.get_or(|| {
                 let file = BufWriter::new(spooled_tempfile(
@@ -162,11 +166,13 @@ impl WordPrefixIntegerDocids {
         database: Database<Bytes, CboRoaringBitmapCodec>,
         prefix_database: Database<Bytes, CboRoaringBitmapCodec>,
         grenad_parameters: &GrenadParameters,
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
     ) -> WordPrefixIntegerDocids {
         WordPrefixIntegerDocids {
             database,
             prefix_database,
-            max_memory_by_thread: grenad_parameters.max_memory_by_thread(),
+            max_memory_by_thread: grenad_parameters
+                .max_memory_by_thread(thread_pool.thread_count()),
         }
     }
 
@@ -175,9 +181,10 @@ impl WordPrefixIntegerDocids {
         wtxn: &mut heed::RwTxn,
         prefix_to_compute: &BTreeSet<Prefix>,
         prefix_to_delete: &BTreeSet<Prefix>,
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
     ) -> Result<()> {
         delete_prefixes(wtxn, &self.prefix_database, prefix_to_delete)?;
-        self.recompute_modified_prefixes(wtxn, prefix_to_compute)
+        self.recompute_modified_prefixes(wtxn, prefix_to_compute, thread_pool)
     }
 
     #[tracing::instrument(level = "trace", skip_all, target = "indexing::prefix")]
@@ -185,6 +192,7 @@ impl WordPrefixIntegerDocids {
         &self,
         wtxn: &mut RwTxn,
         prefixes: &BTreeSet<Prefix>,
+        thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
     ) -> Result<()> {
         // We fetch the docids associated to the newly added word prefix fst only.
         // And collect the CboRoaringBitmaps pointers in an HashMap.
@@ -192,7 +200,7 @@ impl WordPrefixIntegerDocids {
 
         // We access this HashMap in parallel to compute the *union* of all
         // of them and *serialize* them into files. There is one file by CPU.
-        let local_entries = ThreadLocal::with_capacity(rayon::current_num_threads());
+        let local_entries = ThreadLocal::with_capacity(thread_pool.thread_count());
         prefixes.into_par_iter().map(AsRef::as_ref).try_for_each(|prefix| {
             let refcell = local_entries.get_or(|| {
                 let file = BufWriter::new(spooled_tempfile(
@@ -312,13 +320,15 @@ pub fn compute_word_prefix_docids(
     prefix_to_compute: &BTreeSet<Prefix>,
     prefix_to_delete: &BTreeSet<Prefix>,
     grenad_parameters: &GrenadParameters,
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
 ) -> Result<()> {
     WordPrefixDocids::new(
         index.word_docids.remap_key_type(),
         index.word_prefix_docids.remap_key_type(),
         grenad_parameters,
+        thread_pool,
     )
-    .execute(wtxn, prefix_to_compute, prefix_to_delete)
+    .execute(wtxn, prefix_to_compute, prefix_to_delete, thread_pool)
 }
 
 #[tracing::instrument(level = "trace", skip_all, target = "indexing::prefix")]
@@ -328,13 +338,15 @@ pub fn compute_exact_word_prefix_docids(
     prefix_to_compute: &BTreeSet<Prefix>,
     prefix_to_delete: &BTreeSet<Prefix>,
     grenad_parameters: &GrenadParameters,
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
 ) -> Result<()> {
     WordPrefixDocids::new(
         index.exact_word_docids.remap_key_type(),
         index.exact_word_prefix_docids.remap_key_type(),
         grenad_parameters,
+        thread_pool,
     )
-    .execute(wtxn, prefix_to_compute, prefix_to_delete)
+    .execute(wtxn, prefix_to_compute, prefix_to_delete, thread_pool)
 }
 
 #[tracing::instrument(level = "trace", skip_all, target = "indexing::prefix")]
@@ -344,13 +356,15 @@ pub fn compute_word_prefix_fid_docids(
     prefix_to_compute: &BTreeSet<Prefix>,
     prefix_to_delete: &BTreeSet<Prefix>,
     grenad_parameters: &GrenadParameters,
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
 ) -> Result<()> {
     WordPrefixIntegerDocids::new(
         index.word_fid_docids.remap_key_type(),
         index.word_prefix_fid_docids.remap_key_type(),
         grenad_parameters,
+        thread_pool,
     )
-    .execute(wtxn, prefix_to_compute, prefix_to_delete)
+    .execute(wtxn, prefix_to_compute, prefix_to_delete, thread_pool)
 }
 
 #[tracing::instrument(level = "trace", skip_all, target = "indexing::prefix")]
@@ -360,11 +374,13 @@ pub fn compute_word_prefix_position_docids(
     prefix_to_compute: &BTreeSet<Prefix>,
     prefix_to_delete: &BTreeSet<Prefix>,
     grenad_parameters: &GrenadParameters,
+    thread_pool: &scoped_thread_pool::ThreadPool<crate::Error>,
 ) -> Result<()> {
     WordPrefixIntegerDocids::new(
         index.word_position_docids.remap_key_type(),
         index.word_prefix_position_docids.remap_key_type(),
         grenad_parameters,
+        thread_pool,
     )
-    .execute(wtxn, prefix_to_compute, prefix_to_delete)
+    .execute(wtxn, prefix_to_compute, prefix_to_delete, thread_pool)
 }

crates/milli/tests/search/facet_distribution.rs

@@ -5,6 +5,7 @@ use maplit::hashset;
 use milli::documents::mmap_from_objects;
 use milli::progress::Progress;
 use milli::update::new::indexer;
+use milli::update::new::indexer::document_changes::CHUNK_SIZE;
 use milli::update::{IndexDocumentsMethod, IndexerConfig, Settings};
 use milli::vector::EmbeddingConfigs;
 use milli::{FacetDistribution, Index, Object, OrderBy};
@@ -36,6 +37,8 @@ fn test_facet_distribution_with_no_facet_values() {
     let mut new_fields_ids_map = db_fields_ids_map.clone();
 
     let embedders = EmbeddingConfigs::default();
+    let thread_pool =
+        scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
     let mut indexer = indexer::DocumentOperation::new(IndexDocumentsMethod::ReplaceDocuments);
 
     let doc1: Object = from_value(
@@ -59,12 +62,15 @@ fn test_facet_distribution_with_no_facet_values() {
             &mut new_fields_ids_map,
             &|| false,
             Progress::default(),
+            &thread_pool,
+            CHUNK_SIZE,
         )
         .unwrap();
 
     indexer::index(
         &mut wtxn,
         &index,
+        &thread_pool,
         &milli::ThreadPoolNoAbortBuilder::new().build().unwrap(),
         config.grenad_parameters(),
         &db_fields_ids_map,

crates/milli/tests/search/mod.rs

@@ -9,6 +9,7 @@ use heed::EnvOpenOptions;
 use maplit::{btreemap, hashset};
 use milli::progress::Progress;
 use milli::update::new::indexer;
+use milli::update::new::indexer::document_changes::CHUNK_SIZE;
 use milli::update::{IndexDocumentsMethod, IndexerConfig, Settings};
 use milli::vector::EmbeddingConfigs;
 use milli::{AscDesc, Criterion, DocumentId, Index, Member, TermsMatchingStrategy};
@@ -72,6 +73,8 @@ pub fn setup_search_index_with_criteria(criteria: &[Criterion]) -> Index {
     let mut new_fields_ids_map = db_fields_ids_map.clone();
 
     let embedders = EmbeddingConfigs::default();
+    let thread_pool =
+        scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
     let mut indexer = indexer::DocumentOperation::new(IndexDocumentsMethod::ReplaceDocuments);
 
     let mut file = tempfile::tempfile().unwrap();
@@ -92,6 +95,8 @@ pub fn setup_search_index_with_criteria(criteria: &[Criterion]) -> Index {
             &mut new_fields_ids_map,
             &|| false,
             Progress::default(),
+            &thread_pool,
+            CHUNK_SIZE,
         )
         .unwrap();
 
@@ -102,6 +107,7 @@ pub fn setup_search_index_with_criteria(criteria: &[Criterion]) -> Index {
     indexer::index(
         &mut wtxn,
         &index,
+        &thread_pool,
         &milli::ThreadPoolNoAbortBuilder::new().build().unwrap(),
         config.grenad_parameters(),
         &db_fields_ids_map,

crates/milli/tests/search/query_criteria.rs

@@ -7,6 +7,7 @@ use itertools::Itertools;
 use maplit::hashset;
 use milli::progress::Progress;
 use milli::update::new::indexer;
+use milli::update::new::indexer::document_changes::CHUNK_SIZE;
 use milli::update::{IndexDocumentsMethod, IndexerConfig, Settings};
 use milli::vector::EmbeddingConfigs;
 use milli::{AscDesc, Criterion, Index, Member, Search, SearchResult, TermsMatchingStrategy};
@@ -288,6 +289,8 @@ fn criteria_ascdesc() {
     let mut new_fields_ids_map = db_fields_ids_map.clone();
 
     let embedders = EmbeddingConfigs::default();
+    let thread_pool =
+        scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
     let mut indexer = indexer::DocumentOperation::new(IndexDocumentsMethod::ReplaceDocuments);
 
     let mut file = tempfile::tempfile().unwrap();
@@ -328,12 +331,15 @@ fn criteria_ascdesc() {
             &mut new_fields_ids_map,
             &|| false,
             Progress::default(),
+            &thread_pool,
+            CHUNK_SIZE,
         )
         .unwrap();
 
     indexer::index(
         &mut wtxn,
         &index,
+        &thread_pool,
         &milli::ThreadPoolNoAbortBuilder::new().build().unwrap(),
         config.grenad_parameters(),
         &db_fields_ids_map,

crates/milli/tests/search/typo_tolerance.rs

@@ -5,6 +5,7 @@ use heed::EnvOpenOptions;
 use milli::documents::mmap_from_objects;
 use milli::progress::Progress;
 use milli::update::new::indexer;
+use milli::update::new::indexer::document_changes::CHUNK_SIZE;
 use milli::update::{IndexDocumentsMethod, IndexerConfig, Settings};
 use milli::vector::EmbeddingConfigs;
 use milli::{Criterion, Index, Object, Search, TermsMatchingStrategy};
@@ -123,6 +124,8 @@ fn test_typo_disabled_on_word() {
     let db_fields_ids_map = index.fields_ids_map(&rtxn).unwrap();
     let mut new_fields_ids_map = db_fields_ids_map.clone();
     let embedders = EmbeddingConfigs::default();
+    let thread_pool =
+        scoped_thread_pool::ThreadPool::with_available_parallelism("index".to_string());
     let mut indexer = indexer::DocumentOperation::new(IndexDocumentsMethod::ReplaceDocuments);
 
     indexer.add_documents(&documents).unwrap();
@@ -137,12 +140,15 @@ fn test_typo_disabled_on_word() {
             &mut new_fields_ids_map,
             &|| false,
             Progress::default(),
+            &thread_pool,
+            CHUNK_SIZE,
         )
         .unwrap();
 
     indexer::index(
         &mut wtxn,
         &index,
+        &thread_pool,
         &milli::ThreadPoolNoAbortBuilder::new().build().unwrap(),
         config.grenad_parameters(),
         &db_fields_ids_map,