From 84ce75d2e89e3391d233c29a514980ee20c37ddf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dani=C3=ABl=20van=20Eeden?= <git@myname.nl>
Date: Tue, 14 Sep 2021 21:10:41 +0200
Subject: [PATCH] server, session: Reduce noise from SELECT...FOR UPDATE NOWAIT
 (#26845)

---
 server/conn.go     | 20 ++++++++++++--------
 session/session.go | 11 +++++++++--
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/server/conn.go b/server/conn.go
index be20a7c2763e2..0e43868b95792 100644
--- a/server/conn.go
+++ b/server/conn.go
@@ -995,14 +995,18 @@ func (cc *clientConn) Run(ctx context.Context) {
 				txnMode = cc.ctx.GetSessionVars().GetReadableTxnMode()
 			}
 			metrics.ExecuteErrorCounter.WithLabelValues(metrics.ExecuteErrorToLabel(err)).Inc()
-			logutil.Logger(ctx).Info("command dispatched failed",
-				zap.String("connInfo", cc.String()),
-				zap.String("command", mysql.Command2Str[data[0]]),
-				zap.String("status", cc.SessionStatusToString()),
-				zap.Stringer("sql", getLastStmtInConn{cc}),
-				zap.String("txn_mode", txnMode),
-				zap.String("err", errStrForLog(err, cc.ctx.GetSessionVars().EnableRedactLog)),
-			)
+			if storeerr.ErrLockAcquireFailAndNoWaitSet.Equal(err) {
+				logutil.Logger(ctx).Debug("Expected error for FOR UPDATE NOWAIT", zap.Error(err))
+			} else {
+				logutil.Logger(ctx).Info("command dispatched failed",
+					zap.String("connInfo", cc.String()),
+					zap.String("command", mysql.Command2Str[data[0]]),
+					zap.String("status", cc.SessionStatusToString()),
+					zap.Stringer("sql", getLastStmtInConn{cc}),
+					zap.String("txn_mode", txnMode),
+					zap.String("err", errStrForLog(err, cc.ctx.GetSessionVars().EnableRedactLog)),
+				)
+			}
 			err1 := cc.writeError(ctx, err)
 			terror.Log(err1)
 		}
diff --git a/session/session.go b/session/session.go
index 9087239fea383..279b82f98ec2d 100644
--- a/session/session.go
+++ b/session/session.go
@@ -74,6 +74,7 @@ import (
 	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/statistics"
 	"github.com/pingcap/tidb/statistics/handle"
+	storeerr "github.com/pingcap/tidb/store/driver/error"
 	"github.com/pingcap/tidb/tablecodec"
 	"github.com/pingcap/tidb/telemetry"
 	"github.com/pingcap/tidb/types"
@@ -670,7 +671,13 @@ func (m temporaryTableKVFilter) IsUnnecessaryKeyValue(key, value []byte, flags t
 // of the errors defined in kv/error.go, these look to be clearly related to a client-inflicted issue,
 // and the server is only responsible for handling the error correctly. It does not need to log.
 func errIsNoisy(err error) bool {
-	return kv.ErrKeyExists.Equal(err)
+	if kv.ErrKeyExists.Equal(err) {
+		return true
+	}
+	if storeerr.ErrLockAcquireFailAndNoWaitSet.Equal(err) {
+		return true
+	}
+	return false
 }
 
 func (s *session) doCommitWithRetry(ctx context.Context) error {
@@ -1568,7 +1575,7 @@ func (s *session) ExecuteStmt(ctx context.Context, stmtNode ast.StmtNode) (sqlex
 	logStmt(stmt, s)
 	recordSet, err := runStmt(ctx, s, stmt)
 	if err != nil {
-		if !kv.ErrKeyExists.Equal(err) {
+		if !errIsNoisy(err) {
 			logutil.Logger(ctx).Warn("run statement failed",
 				zap.Int64("schemaVersion", s.GetInfoSchema().SchemaMetaVersion()),
 				zap.Error(err),