cherry pick pingcap#31110 to release-5.1

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>

session/session_test.go

@@ -59,7 +59,12 @@ import (
 	"github.com/pingcap/tidb/table/tables"
 	"github.com/pingcap/tidb/tablecodec"
 	"github.com/pingcap/tidb/types"
+<<<<<<< HEAD
 	"github.com/pingcap/tidb/util/collate"
+=======
+	"github.com/pingcap/tidb/util"
+	"github.com/pingcap/tidb/util/memory"
+>>>>>>> 09edaee06... store: avoid setting ratelimit action in tracker when disabled (#31110)
 	"github.com/pingcap/tidb/util/sqlexec"
 	"github.com/pingcap/tidb/util/testkit"
 	"github.com/pingcap/tidb/util/testleak"
@@ -3599,6 +3604,18 @@ func (s *testSessionSuite2) TestSetEnableRateLimitAction(c *C) {
 	// assert default value
 	result := tk.MustQuery("select @@tidb_enable_rate_limit_action;")
 	result.Check(testkit.Rows("1"))
+	tk.MustExec("use test")
+	tk.MustExec("create table tmp123(id int)")
+	tk.MustQuery("select * from tmp123;")
+	haveRateLimitAction := false
+	action := tk.Se.GetSessionVars().StmtCtx.MemTracker.GetFallbackForTest()
+	for ; action != nil; action = action.GetFallback() {
+		if action.GetPriority() == memory.DefRateLimitPriority {
+			haveRateLimitAction = true
+			break
+		}
+	}
+	c.Assert(haveRateLimitAction, IsTrue)
 
 	// assert set sys variable
 	tk.MustExec("set global tidb_enable_rate_limit_action= '0';")
@@ -3609,6 +3626,16 @@ func (s *testSessionSuite2) TestSetEnableRateLimitAction(c *C) {
 	tk.Se = se
 	result = tk.MustQuery("select @@tidb_enable_rate_limit_action;")
 	result.Check(testkit.Rows("0"))
+
+	haveRateLimitAction = false
+	action = tk.Se.GetSessionVars().StmtCtx.MemTracker.GetFallbackForTest()
+	for ; action != nil; action = action.GetFallback() {
+		if action.GetPriority() == memory.DefRateLimitPriority {
+			haveRateLimitAction = true
+			break
+		}
+	}
+	c.Assert(haveRateLimitAction, IsFalse)
 }
 
 func (s *testSessionSuite3) TestSetVarHint(c *C) {

store/copr/coprocessor.go

@@ -117,7 +117,7 @@ func (c *CopClient) Send(ctx context.Context, req *kv.Request, variables interfa
 		it.sendRate = util.NewRateLimit(it.concurrency)
 	}
 	it.actionOnExceed = newRateLimitAction(uint(it.sendRate.GetCapacity()))
-	if sessionMemTracker != nil {
+	if sessionMemTracker != nil && enabledRateLimitAction {
 		sessionMemTracker.FallbackOldAndSetNewAction(it.actionOnExceed)
 	}