From 6d0ffe457e317bc172f0c8228e0e7c8e35eb2bd6 Mon Sep 17 00:00:00 2001
From: ti-srebot <66930949+ti-srebot@users.noreply.github.com>
Date: Tue, 26 Jan 2021 22:27:54 +0800
Subject: [PATCH] session: set process info before building plan (#22101)
 (#22148)

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>
---
 session/session.go      | 11 ++++++++++-
 session/session_test.go | 18 ++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/session/session.go b/session/session.go
index c1a5bde3551ff..07ecaa1b486ab 100644
--- a/session/session.go
+++ b/session/session.go
@@ -1080,16 +1080,20 @@ func (s *session) SetProcessInfo(sql string, t time.Time, command byte, maxExecu
 		MaxExecutionTime: maxExecutionTime,
 		RedactSQL:        s.sessionVars.EnableRedactLog,
 	}
+	oldPi := s.ShowProcess()
 	if p == nil {
 		// Store the last valid plan when the current plan is nil.
 		// This is for `explain for connection` statement has the ability to query the last valid plan.
-		oldPi := s.ShowProcess()
 		if oldPi != nil && oldPi.Plan != nil && len(oldPi.PlanExplainRows) > 0 {
 			pi.Plan = oldPi.Plan
 			pi.PlanExplainRows = oldPi.PlanExplainRows
 			pi.RuntimeStatsColl = oldPi.RuntimeStatsColl
 		}
 	}
+	// We set process info before building plan, so we extended execution time.
+	if oldPi != nil && oldPi.Info == pi.Info {
+		pi.Time = oldPi.Time
+	}
 	_, pi.Digest = s.sessionVars.StmtCtx.SQLDigest()
 	s.currentPlan = nil
 	if s.sessionVars.User != nil {
@@ -1212,6 +1216,11 @@ func (s *session) execute(ctx context.Context, sql string) (recordSets []sqlexec
 		if err := executor.ResetContextOfStmt(s, stmtNode); err != nil {
 			return nil, err
 		}
+
+		// Uncorrelated subqueries will execute once when building plan, so we reset process info before building plan.
+		cmd32 := atomic.LoadUint32(&s.GetSessionVars().CommandValue)
+		s.SetProcessInfo(stmtNode.Text(), time.Now(), byte(cmd32), 0)
+
 		stmt, err := compiler.Compile(ctx, stmtNode)
 		if err != nil {
 			s.rollbackOnError(ctx)
diff --git a/session/session_test.go b/session/session_test.go
index dc0811557af68..0da6852f1e114 100644
--- a/session/session_test.go
+++ b/session/session_test.go
@@ -3466,3 +3466,21 @@ func (s *testSessionSerialSuite) TestDefaultWeekFormat(c *C) {
 	tk2 := testkit.NewTestKitWithInit(c, s.store)
 	tk2.MustQuery("select week('2020-02-02'), @@default_week_format, week('2020-02-02');").Check(testkit.Rows("6 4 6"))
 }
+
+func (s *testSessionSerialSuite) TestProcessInfoIssue22068(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("create table t(a int)")
+	wg := sync.WaitGroup{}
+	wg.Add(1)
+	go func() {
+		tk.MustQuery("select 1 from t where a = (select sleep(5));").Check(testkit.Rows())
+		wg.Done()
+	}()
+	time.Sleep(2 * time.Second)
+	pi := tk.Se.ShowProcess()
+	c.Assert(pi, NotNil)
+	c.Assert(pi.Info, Equals, "select 1 from t where a = (select sleep(5));")
+	c.Assert(pi.Plan, IsNil)
+	wg.Wait()
+}