From ac60c03e379e481cce2634872d6785a5d1f5d30e Mon Sep 17 00:00:00 2001
From: Feng Liyuan <darktemplar.f@gmail.com>
Date: Thu, 20 Aug 2020 17:45:47 +0800
Subject: [PATCH] cherry pick #19316 to release-3.1

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>
---
 executor/seqtest/prepared_test.go | 70 +++++++++++++++++++++++++++++++
 planner/core/util.go              |  5 +++
 2 files changed, 75 insertions(+)

diff --git a/executor/seqtest/prepared_test.go b/executor/seqtest/prepared_test.go
index f6140b074d09f..a7c8bd5db5b6f 100644
--- a/executor/seqtest/prepared_test.go
+++ b/executor/seqtest/prepared_test.go
@@ -15,12 +15,22 @@ package executor_test
 
 import (
 	"context"
+	"crypto/tls"
 	"math"
+	"time"
 
 	. "github.com/pingcap/check"
+	"github.com/pingcap/parser/mysql"
 	"github.com/pingcap/tidb/executor"
 	"github.com/pingcap/tidb/metrics"
 	plannercore "github.com/pingcap/tidb/planner/core"
+<<<<<<< HEAD
+=======
+	"github.com/pingcap/tidb/session"
+	"github.com/pingcap/tidb/types"
+	"github.com/pingcap/tidb/util"
+	"github.com/pingcap/tidb/util/kvcache"
+>>>>>>> 57e43bd... planner: workaround the panic of command EXECUTE when printing an expensive query log (#19316)
 	"github.com/pingcap/tidb/util/testkit"
 	dto "github.com/prometheus/client_model/go"
 )
@@ -757,3 +767,63 @@ func (s *seqTestSuite) TestPreparedIssue8644(c *C) {
 		r.Check(testkit.Rows("a", "aaaaaaaaaaaaaaaaaa"))
 	}
 }
+
+// mockSessionManager is a mocked session manager which is used for test.
+type mockSessionManager1 struct {
+	Se session.Session
+}
+
+// ShowProcessList implements the SessionManager.ShowProcessList interface.
+func (msm *mockSessionManager1) ShowProcessList() map[uint64]*util.ProcessInfo {
+	ret := make(map[uint64]*util.ProcessInfo)
+	return ret
+}
+
+func (msm *mockSessionManager1) GetProcessInfo(id uint64) (*util.ProcessInfo, bool) {
+	pi := msm.Se.ShowProcess()
+	return pi, true
+}
+
+// Kill implements the SessionManager.Kill interface.
+func (msm *mockSessionManager1) Kill(cid uint64, query bool) {}
+
+func (msm *mockSessionManager1) UpdateTLSConfig(cfg *tls.Config) {}
+
+func (s *seqTestSuite) TestPreparedIssue17419(c *C) {
+	ctx := context.Background()
+	tk := testkit.NewTestKit(c, s.store)
+
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t (a int)")
+	tk.MustExec("insert into t (a) values (1), (2), (3)")
+
+	tk1 := testkit.NewTestKit(c, s.store)
+
+	var err error
+	tk1.Se, err = session.CreateSession4Test(s.store)
+	c.Assert(err, IsNil)
+	tk1.GetConnectionID()
+
+	query := "select * from test.t"
+	stmtID, _, _, err := tk1.Se.PrepareStmt(query)
+	c.Assert(err, IsNil)
+
+	sm := &mockSessionManager1{
+		Se: tk1.Se,
+	}
+	tk1.Se.SetSessionManager(sm)
+	s.domain.ExpensiveQueryHandle().SetSessionManager(sm)
+
+	rs, err := tk1.Se.ExecutePreparedStmt(ctx, stmtID, []types.Datum{})
+	c.Assert(err, IsNil)
+	tk1.ResultSetToResult(rs, Commentf("%v", rs)).Check(testkit.Rows("1", "2", "3"))
+	tk1.Se.SetProcessInfo("", time.Now(), mysql.ComStmtExecute, 0)
+
+	s.domain.ExpensiveQueryHandle().LogOnQueryExceedMemQuota(tk.Se.GetSessionVars().ConnectionID)
+
+	// After entirely fixing https://github.com/pingcap/tidb/issues/17419
+	// c.Assert(tk1.Se.ShowProcess().Plan, NotNil)
+	// _, ok := tk1.Se.ShowProcess().Plan.(*plannercore.Execute)
+	// c.Assert(ok, IsTrue)
+}
diff --git a/planner/core/util.go b/planner/core/util.go
index 4d6fd39973712..12fceb060db27 100644
--- a/planner/core/util.go
+++ b/planner/core/util.go
@@ -169,6 +169,11 @@ func buildPhysicalJoinSchema(joinType JoinType, join PhysicalPlan) *expression.S
 
 // GetStatsInfo gets the statistics info from a physical plan tree.
 func GetStatsInfo(i interface{}) map[string]uint64 {
+	if i == nil {
+		// it's a workaround for https://github.com/pingcap/tidb/issues/17419
+		// To entirely fix this, uncomment the assertion in TestPreparedIssue17419
+		return nil
+	}
 	p := i.(Plan)
 	var physicalPlan PhysicalPlan
 	switch x := p.(type) {