From 224d797f9499298cf89b1e1406e26f7cc44bf832 Mon Sep 17 00:00:00 2001
From: congqixia <congqi.xia@zilliz.com>
Date: Tue, 29 Oct 2024 10:02:24 +0800
Subject: [PATCH] fix: Use singleton delete pool and avoid goroutine leakage
 (#37220)

Related to #36887

Previously using newly create pool per request shall cause goroutine
leakage. This PR change this behavior by using singleton delete pool.
This change could also provide better concurrency control over delete
memory usage.

Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>
---
 internal/querynodev2/segments/pool.go | 15 +++++++++++++++
 internal/querynodev2/services.go      |  3 +--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/internal/querynodev2/segments/pool.go b/internal/querynodev2/segments/pool.go
index 7557c853dc..7bddca6169 100644
--- a/internal/querynodev2/segments/pool.go
+++ b/internal/querynodev2/segments/pool.go
@@ -46,6 +46,9 @@ var (
 	warmupPool atomic.Pointer[conc.Pool[any]]
 	warmupOnce sync.Once
 
+	deletePool     atomic.Pointer[conc.Pool[struct{}]]
+	deletePoolOnce sync.Once
+
 	bfPool      atomic.Pointer[conc.Pool[any]]
 	bfApplyOnce sync.Once
 )
@@ -131,6 +134,13 @@ func initBFApplyPool() {
 	})
 }
 
+func initDeletePool() {
+	deletePoolOnce.Do(func() {
+		pool := conc.NewPool[struct{}](runtime.GOMAXPROCS(0))
+		deletePool.Store(pool)
+	})
+}
+
 // GetSQPool returns the singleton pool instance for search/query operations.
 func GetSQPool() *conc.Pool[any] {
 	initSQPool()
@@ -158,6 +168,11 @@ func GetBFApplyPool() *conc.Pool[any] {
 	return bfPool.Load()
 }
 
+func GetDeletePool() *conc.Pool[struct{}] {
+	initDeletePool()
+	return deletePool.Load()
+}
+
 func ResizeSQPool(evt *config.Event) {
 	if evt.HasUpdated {
 		pt := paramtable.Get()
diff --git a/internal/querynodev2/services.go b/internal/querynodev2/services.go
index 642ed964ee..085154f696 100644
--- a/internal/querynodev2/services.go
+++ b/internal/querynodev2/services.go
@@ -19,7 +19,6 @@ package querynodev2
 import (
 	"context"
 	"fmt"
-	"runtime"
 	"strconv"
 	"sync"
 	"time"
@@ -1423,7 +1422,7 @@ func (node *QueryNode) DeleteBatch(ctx context.Context, req *querypb.DeleteBatch
 
 	// control the execution batch parallel with P number
 	// maybe it shall be lower in case of heavy CPU usage may impacting search/query
-	pool := conc.NewPool[struct{}](runtime.GOMAXPROCS(0))
+	pool := segments.GetDeletePool()
 	futures := make([]*conc.Future[struct{}], 0, len(segs))
 	errSet := typeutil.NewConcurrentSet[int64]()