From 6254c7cee15748b3908eafab4220e2fb938da87d Mon Sep 17 00:00:00 2001
From: Louis Dureuil <louis@meilisearch.com>
Date: Wed, 19 Jun 2024 13:57:44 +0200
Subject: [PATCH] Only spawn the pool once

---
 .../src/update/index_documents/extract/mod.rs | 23 +++++++++++++------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/milli/src/update/index_documents/extract/mod.rs b/milli/src/update/index_documents/extract/mod.rs
index 237e19b2a..6935717dc 100644
--- a/milli/src/update/index_documents/extract/mod.rs
+++ b/milli/src/update/index_documents/extract/mod.rs
@@ -11,7 +11,7 @@ mod extract_word_position_docids;
 
 use std::fs::File;
 use std::io::BufReader;
-use std::sync::Arc;
+use std::sync::{Arc, OnceLock};
 
 use crossbeam_channel::Sender;
 use rayon::prelude::*;
@@ -31,7 +31,7 @@ use self::extract_word_position_docids::extract_word_position_docids;
 use super::helpers::{as_cloneable_grenad, CursorClonableMmap, GrenadParameters};
 use super::{helpers, TypedChunk};
 use crate::update::settings::InnerIndexSettingsDiff;
-use crate::{FieldId, Result, ThreadPoolNoAbortBuilder};
+use crate::{FieldId, Result, ThreadPoolNoAbort, ThreadPoolNoAbortBuilder};
 
 /// Extract data for each databases from obkv documents in parallel.
 /// Send data in grenad file over provided Sender.
@@ -213,6 +213,18 @@ fn run_extraction_task<FE, FS, M>(
     })
 }
 
+fn request_threads() -> &'static ThreadPoolNoAbort {
+    static REQUEST_THREADS: OnceLock<ThreadPoolNoAbort> = OnceLock::new();
+
+    REQUEST_THREADS.get_or_init(|| {
+        ThreadPoolNoAbortBuilder::new()
+            .num_threads(crate::vector::REQUEST_PARALLELISM)
+            .thread_name(|index| format!("embedding-request-{index}"))
+            .build()
+            .unwrap()
+    })
+}
+
 /// Extract chunked data and send it into lmdb_writer_sx sender:
 /// - documents
 fn send_original_documents_data(
@@ -227,10 +239,7 @@ fn send_original_documents_data(
     let documents_chunk_cloned = original_documents_chunk.clone();
     let lmdb_writer_sx_cloned = lmdb_writer_sx.clone();
 
-    let request_threads = ThreadPoolNoAbortBuilder::new()
-        .num_threads(crate::vector::REQUEST_PARALLELISM)
-        .thread_name(|index| format!("embedding-request-{index}"))
-        .build()?;
+    let request_threads = request_threads();
 
     if settings_diff.reindex_vectors() || !settings_diff.settings_update_only() {
         let settings_diff = settings_diff.clone();
@@ -249,7 +258,7 @@ fn send_original_documents_data(
                             prompts,
                             indexer,
                             embedder.clone(),
-                            &request_threads,
+                            request_threads,
                         ) {
                             Ok(results) => Some(results),
                             Err(error) => {