From 01f72bf91a13190a9bad062f46c4853c2adb1755 Mon Sep 17 00:00:00 2001
From: ti-srebot <66930949+ti-srebot@users.noreply.github.com>
Date: Tue, 22 Feb 2022 20:33:45 +0800
Subject: [PATCH] executor: fix pipelined window invalid memory address
 (#30418) (#30460)

close pingcap/tidb#30326
---
 executor/pipelined_window.go   |  2 +-
 expression/integration_test.go | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/executor/pipelined_window.go b/executor/pipelined_window.go
index 8e120376402be..7e8f6a0ed5c5e 100644
--- a/executor/pipelined_window.go
+++ b/executor/pipelined_window.go
@@ -179,7 +179,7 @@ func (e *PipelinedWindowExec) getRowsInPartition(ctx context.Context) (err error
 		var drained, samePartition bool
 		drained, err = e.fetchChild(ctx)
 		if err != nil {
-			err = errors.Trace(err)
+			return errors.Trace(err)
 		}
 		// we return immediately to use a combination of true newPartition but 0 in e.rowToConsume to indicate the data source is drained,
 		if drained {
diff --git a/expression/integration_test.go b/expression/integration_test.go
index 278da84826f52..acfefb2095748 100644
--- a/expression/integration_test.go
+++ b/expression/integration_test.go
@@ -10548,3 +10548,15 @@ func (s *testIntegrationSuite) TestIssue29513(c *C) {
 	tk.MustQuery("select '123' union select cast(a as char) from t;").Sort().Check(testkit.Rows("123", "45678"))
 	tk.MustQuery("select '123' union select cast(a as char(2)) from t;").Sort().Check(testkit.Rows("123", "45"))
 }
+
+func (s *testIntegrationSuite) TestIssue30326(c *C) {
+	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 values(1),(1),(2),(2);")
+	tk.MustExec("set tidb_window_concurrency = 1;")
+	err := tk.QueryToErr("select (FIRST_VALUE(1) over (partition by v.a)) as c3 from (select a from t where t.a = (select a from t t2 where t.a = t2.a)) as v;")
+	c.Assert(err, NotNil)
+	c.Assert(err.Error(), Equals, "[executor:1242]Subquery returns more than 1 row")
+}