planner: better coordination between the ignore_plan_cache() binding …

…and plan-cache (#40280) (#41444)

close #40225

planner/core/plan_cache.go

@@ -126,14 +126,19 @@ func GetPlanFromSessionPlanCache(ctx context.Context, sctx sessionctx.Context,
 	stmtCtx.UseCache = stmtAst.UseCache
 
 	var bindSQL string
-	var ignorePlanCache = false
+	if stmtCtx.UseCache {
+		var ignoreByBinding bool
+		bindSQL, ignoreByBinding = GetBindSQL4PlanCache(sctx, stmt)
+		if ignoreByBinding {
+			stmtCtx.SetSkipPlanCache(errors.Errorf("skip plan-cache: ignore plan cache by binding"))
+		}
+	}
 
 	// In rc or for update read, we need the latest schema version to decide whether we need to
 	// rebuild the plan. So we set this value in rc or for update read. In other cases, let it be 0.
 	var latestSchemaVersion int64
 
-	if stmtAst.UseCache {
-		bindSQL, ignorePlanCache = GetBindSQL4PlanCache(sctx, stmt)
+	if stmtCtx.UseCache {
 		if sctx.GetSessionVars().IsIsolation(ast.ReadCommitted) || stmt.ForUpdateRead {
 			// In Rc or ForUpdateRead, we should check if the information schema has been changed since
 			// last time. If it changed, we should rebuild the plan. Here, we use a different and more
@@ -148,21 +153,20 @@ func GetPlanFromSessionPlanCache(ctx context.Context, sctx sessionctx.Context,
 
 	paramNum, paramTypes := parseParamTypes(sctx, params)
 
-	if stmtAst.UseCache && stmtAst.CachedPlan != nil && !ignorePlanCache { // for point query plan
+	if stmtCtx.UseCache && stmtAst.CachedPlan != nil { // for point query plan
 		if plan, names, ok, err := getPointQueryPlan(stmtAst, sessVars, stmtCtx); ok {
 			return plan, names, err
 		}
 	}
 
-	if stmtAst.UseCache && !ignorePlanCache { // for general plans
+	if stmtCtx.UseCache { // for non-point plans
 		if plan, names, ok, err := getGeneralPlan(sctx, isGeneralPlanCache, cacheKey, bindSQL, is, stmt,
 			paramTypes); err != nil || ok {
 			return plan, names, err
 		}
 	}
 
-	return generateNewPlan(ctx, sctx, isGeneralPlanCache, is, stmt, ignorePlanCache, cacheKey,
-		latestSchemaVersion, paramNum, paramTypes, bindSQL)
+	return generateNewPlan(ctx, sctx, isGeneralPlanCache, is, stmt, cacheKey, latestSchemaVersion, paramNum, paramTypes, bindSQL)
 }
 
 // parseParamTypes get parameters' types in PREPARE statement
@@ -253,8 +257,7 @@ func getGeneralPlan(sctx sessionctx.Context, isGeneralPlanCache bool, cacheKey k
 
 // generateNewPlan call the optimizer to generate a new plan for current statement
 // and try to add it to cache
-func generateNewPlan(ctx context.Context, sctx sessionctx.Context, isGeneralPlanCache bool, is infoschema.InfoSchema, stmt *PlanCacheStmt,
-	ignorePlanCache bool, cacheKey kvcache.Key, latestSchemaVersion int64, paramNum int,
+func generateNewPlan(ctx context.Context, sctx sessionctx.Context, isGeneralPlanCache bool, is infoschema.InfoSchema, stmt *PlanCacheStmt, cacheKey kvcache.Key, latestSchemaVersion int64, paramNum int,
 	paramTypes []*types.FieldType, bindSQL string) (Plan, []*types.FieldName, error) {
 	stmtAst := stmt.PreparedAst
 	sessVars := sctx.GetSessionVars()
@@ -276,7 +279,7 @@ func generateNewPlan(ctx context.Context, sctx sessionctx.Context, isGeneralPlan
 	if containTableDual(p) && paramNum > 0 {
 		stmtCtx.SetSkipPlanCache(errors.New("skip plan-cache: get a TableDual plan"))
 	}
-	if stmtCtx.UseCache && !ignorePlanCache {
+	if stmtCtx.UseCache {
 		// rebuild key to exclude kv.TiFlash when stmt is not read only
 		if _, isolationReadContainTiFlash := sessVars.IsolationReadEngines[kv.TiFlash]; isolationReadContainTiFlash && !IsReadOnly(stmtAst.Stmt, sessVars) {
 			delete(sessVars.IsolationReadEngines, kv.TiFlash)

planner/core/plan_cache_test.go

@@ -314,6 +314,32 @@ func TestPlanCacheDiagInfo(t *testing.T) {
 	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1105 skip plan-cache: some parameters may be overwritten"))
 }
 
+func TestIssue40225(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("create table t (a int, key(a))")
+	tk.MustExec("prepare st from 'select * from t where a<?'")
+	tk.MustExec("set @a='1'")
+	tk.MustExec("execute st using @a")
+	tk.MustQuery("show warnings").Sort().Check(testkit.Rows("Warning 1105 skip plan-cache: '1' may be converted to INT")) // plan-cache limitation
+	tk.MustExec("create binding for select * from t where a<1 using select /*+ ignore_plan_cache() */ * from t where a<1")
+	tk.MustExec("execute st using @a")
+	tk.MustQuery("show warnings").Sort().Check(testkit.Rows("Warning 1105 skip plan-cache: ignore plan cache by binding"))
+	// no warning about plan-cache limitations('1' -> INT) since plan-cache is totally disabled.
+
+	tk.MustExec("prepare st from 'select * from t where a>?'")
+	tk.MustExec("set @a=1")
+	tk.MustExec("execute st using @a")
+	tk.MustExec("execute st using @a")
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
+	tk.MustExec("create binding for select * from t where a>1 using select /*+ ignore_plan_cache() */ * from t where a>1")
+	tk.MustExec("execute st using @a")
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
+	tk.MustExec("execute st using @a")
+	tk.MustQuery("select @@last_plan_from_binding").Check(testkit.Rows("1"))
+}
+
 func TestIssue40224(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)