This is an automated cherry-pick of pingcap#49357

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>

planner/core/plan_cache_utils.go

@@ -88,9 +88,18 @@ func GeneratePlanCacheStmtWithAST(ctx context.Context, sctx sessionctx.Context,
 		return nil, nil, 0, ErrPrepareDDL
 	}
 
+<<<<<<< HEAD:planner/core/plan_cache_utils.go
 	switch paramStmt.(type) {
 	case *ast.LoadDataStmt, *ast.PrepareStmt, *ast.ExecuteStmt, *ast.DeallocateStmt, *ast.NonTransactionalDMLStmt:
+=======
+	switch stmt := paramStmt.(type) {
+	case *ast.ImportIntoStmt, *ast.LoadDataStmt, *ast.PrepareStmt, *ast.ExecuteStmt, *ast.DeallocateStmt, *ast.NonTransactionalDMLStmt:
+>>>>>>> cf23666766d (planner: return an error when using prepared protocol with select-into statement (#49357)):pkg/planner/core/plan_cache_utils.go
 		return nil, nil, 0, ErrUnsupportedPs
+	case *ast.SelectStmt:
+		if stmt.SelectIntoOpt != nil {
+			return nil, nil, 0, ErrUnsupportedPs
+		}
 	}
 
 	// Prepare parameters should NOT over 2 bytes(MaxUint16)

planner/core/plan_cacheable_checker_test.go

@@ -345,6 +345,14 @@ func TestCacheable(t *testing.T) {
 	require.True(t, core.Cacheable(stmt, is))
 }
 
+func TestIssue49166(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec(`create table t (c int)`)
+	tk.MustContainErrMsg(`prepare stmt from "select c from t limit 1 into outfile 'text'"`, "This command is not supported in the prepared statement protocol yet")
+}
+
 func TestNonPreparedPlanCacheable(t *testing.T) {
 	store := testkit.CreateMockStore(t)