planner: skip plan-cache if some predicates are converted to True/Fal…

…se when constant propagation (#43875) close #43852
pingcap · May 16, 2023 · 0490add · 0490add
1 parent 5db4b38
commit 0490add
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Showing 2 changed files with 42 additions and 1 deletion.
diff --git a/expression/constant_propagation.go b/expression/constant_propagation.go
@@ -15,6 +15,8 @@
 package expression
 
 import (
+	"errors"
+
 	"github.com/pingcap/tidb/parser/ast"
 	"github.com/pingcap/tidb/parser/mysql"
 	"github.com/pingcap/tidb/parser/terror"
@@ -278,6 +280,9 @@ func (s *propConstSolver) propagateColumnEQ() {
 }
 
 func (s *propConstSolver) setConds2ConstFalse() {
+	if MaybeOverOptimized4PlanCache(s.ctx, s.conditions) {
+		s.ctx.GetSessionVars().StmtCtx.SetSkipPlanCache(errors.New("some parameters may be overwritten when constant propagation"))
+	}
 	s.conditions = []Expression{&Constant{
 		Value:   types.NewDatum(false),
 		RetType: types.NewFieldType(mysql.TypeTiny),

diff --git a/planner/core/plan_cache_test.go b/planner/core/plan_cache_test.go
@@ -879,6 +879,18 @@ func TestNonPreparedPlanParameterType(t *testing.T) {
 	tk.MustQuery(`show warnings`).Check(testkit.Rows(`Warning 1105 skip non-prepared plan-cache: '1' may be converted to INT`))
 }
 
+func TestIssue43852(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec(`use test`)
+	tk.MustExec(`create table t6 (a date, b date, key(a))`)
+	tk.MustExec(`insert into t6 values ('2023-01-21', '2023-01-05')`)
+	tk.MustExec(`set tidb_enable_non_prepared_plan_cache=1`)
+	tk.MustQuery(`select * from t6 where a in (2015, '8')`).Check(testkit.Rows())
+	tk.MustQuery(`select * from t6 where a in (2009, '2023-01-21')`).Check(testkit.Rows(`2023-01-21 2023-01-05`))
+	tk.MustQuery(`select @@last_plan_from_cache`).Check(testkit.Rows("0"))
+}
+
 func TestNonPreparedPlanTypeRandomly(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)
@@ -1984,7 +1996,7 @@ func TestNonPreparedPlanExplainWarning(t *testing.T) {
 		"skip non-prepared plan-cache: queries that have generated columns are not supported",
 		"skip non-prepared plan-cache: queries that access views are not supported",
 		"skip non-prepared plan-cache: query has null constants",
-		"skip non-prepared plan-cache: get a TableDual plan",
+		"skip non-prepared plan-cache: some parameters may be overwritten when constant propagation",
 	}
 
 	all := append(supported, unsupported...)
@@ -2280,6 +2292,30 @@ func TestNonPreparedPlanCacheAutoStmtRetry(t *testing.T) {
 	require.ErrorContains(t, tk2Err, "Duplicate entry")
 }
 
+func TestIssue43667Concurrency(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("create table cycle (pk int key, val int)")
+	var wg sync.WaitGroup
+	concurrency := 30
+	for i := 0; i < concurrency; i++ {
+		tk.MustExec(fmt.Sprintf("insert into cycle values (%v,%v)", i, i))
+		wg.Add(1)
+		go func(id int) {
+			defer wg.Done()
+			tk := testkit.NewTestKit(t, store)
+			tk.MustExec("use test")
+			tk.MustExec("set @@tidb_enable_non_prepared_plan_cache=1")
+			query := fmt.Sprintf("select (val) from cycle where pk = %v", id)
+			for j := 0; j < 5000; j++ {
+				tk.MustQuery(query).Check(testkit.Rows(fmt.Sprintf("%v", id)))
+			}
+		}(i)
+	}
+	wg.Wait()
+}
+
 func TestIssue43667(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)