planner: fix plan cache statistic result.

planner/core/prepare_test.go

@@ -751,6 +751,43 @@ func (s *testPlanSerialSuite) TestPlanCacheUnsignedHandleOverflow(c *C) {
 	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
 }
 
+func (s *testPlanSerialSuite) TestIssue18066(c *C) {
+	defer testleak.AfterTest(c)()
+	store, dom, err := newStoreWithBootstrap()
+	c.Assert(err, IsNil)
+	tk := testkit.NewTestKit(c, store)
+	orgEnable := core.PreparedPlanCacheEnabled()
+	defer func() {
+		dom.Close()
+		store.Close()
+		core.SetPreparedPlanCache(orgEnable)
+	}()
+	core.SetPreparedPlanCache(true)
+
+	tk.Se, err = session.CreateSession4TestWithOpt(store, &session.Opt{
+		PreparedPlanCache: kvcache.NewSimpleLRUCache(100, 0.1, math.MaxUint64),
+	})
+	c.Assert(err, IsNil)
+	tk.GetConnectionID()
+	c.Assert(tk.Se.Auth(&auth.UserIdentity{Username: "root", Hostname: "%"}, nil, nil), IsTrue)
+
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t(a int)")
+	tk.MustExec("prepare stmt from 'select * from t'")
+	tk.MustQuery("execute stmt").Check(testkit.Rows())
+	tk.MustQuery("select EXEC_COUNT,plan_cache_hits, plan_in_cache from information_schema.statements_summary where digest_text='select * from t'").Check(
+		testkit.Rows("1 0 0"))
+	tk.MustQuery("execute stmt").Check(testkit.Rows())
+	tk.MustQuery("select EXEC_COUNT,plan_cache_hits, plan_in_cache from information_schema.statements_summary where digest_text='select * from t'").Check(
+		testkit.Rows("2 1 1"))
+	tk.MustExec("prepare stmt from 'select * from t'")
+	tk.MustQuery("execute stmt").Check(testkit.Rows())
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
+	tk.MustQuery("select EXEC_COUNT,plan_cache_hits, plan_in_cache from information_schema.statements_summary where digest_text='select * from t'").Check(
+		testkit.Rows("3 1 0"))
+}
+
 func (s *testPrepareSuite) TestPrepareForGroupByMultiItems(c *C) {
 	defer testleak.AfterTest(c)()
 	store, dom, err := newStoreWithBootstrap()

util/stmtsummary/statement_summary.go

@@ -734,6 +734,8 @@ func (ssElement *stmtSummaryByDigestElement) add(sei *StmtExecInfo, intervalSeco
 	if sei.PlanInCache {
 		ssElement.planInCache = true
 		ssElement.planCacheHits += 1
+	} else {
+		ssElement.planInCache = false
 	}
 
 	// other