statistics: fix data race in the Handle.IsTableLocked (#40572)

close #40567
pingcap · Jan 17, 2023 · b9fb22d · b9fb22d
1 parent aa51b46
commit b9fb22d
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Showing 3 changed files with 14 additions and 3 deletions.
diff --git a/statistics/handle/BUILD.bazel b/statistics/handle/BUILD.bazel
@@ -42,6 +42,7 @@ go_library(
         "//util/memory",
         "//util/ranger",
         "//util/sqlexec",
+        "//util/syncutil",
         "//util/timeutil",
         "@com_github_ngaut_pools//:pools",
         "@com_github_pingcap_errors//:errors",
@@ -72,6 +73,7 @@ go_test(
     ],
     embed = [":handle"],
     flaky = True,
+    race = "on",
     shard_count = 50,
     deps = [
         "//config",

diff --git a/statistics/handle/handle.go b/statistics/handle/handle.go
@@ -48,6 +48,7 @@ import (
 	"github.com/pingcap/tidb/util/mathutil"
 	"github.com/pingcap/tidb/util/memory"
 	"github.com/pingcap/tidb/util/sqlexec"
+	"github.com/pingcap/tidb/util/syncutil"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/tikv/client-go/v2/oracle"
 	atomic2 "go.uber.org/atomic"
@@ -70,7 +71,7 @@ type Handle struct {
 	initStatsCtx sessionctx.Context
 
 	mu struct {
-		sync.RWMutex
+		syncutil.RWMutex
 		ctx sessionctx.Context
 		// rateMap contains the error rate delta from feedback.
 		rateMap errorRateDeltaMap
@@ -361,8 +362,15 @@ func (h *Handle) RemoveLockedTables(tids []int64, pids []int64, tables []*ast.Ta
 	return "", err
 }
 
-// IsTableLocked check whether table is locked in handle
+// IsTableLocked check whether table is locked in handle with Handle.Mutex
 func (h *Handle) IsTableLocked(tableID int64) bool {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return h.isTableLocked(tableID)
+}
+
+// IsTableLocked check whether table is locked in handle without Handle.Mutex
+func (h *Handle) isTableLocked(tableID int64) bool {
 	return isTableLocked(h.tableLocked, tableID)
 }
 

diff --git a/statistics/handle/update.go b/statistics/handle/update.go
@@ -549,7 +549,8 @@ func (h *Handle) dumpTableStatCountToKV(id int64, delta variable.TableDelta) (up
 	startTS := txn.StartTS()
 	updateStatsMeta := func(id int64) error {
 		var err error
-		if h.IsTableLocked(id) {
+		// This lock is already locked on it so it use isTableLocked without lock.
+		if h.isTableLocked(id) {
 			if delta.Delta < 0 {
 				_, err = exec.ExecuteInternal(ctx, "update mysql.stats_table_locked set version = %?, count = count - %?, modify_count = modify_count + %? where table_id = %? and count >= %?", startTS, -delta.Delta, delta.Count, id, -delta.Delta)
 			} else {