Fix error result union scan with apply (#19245)

* fix union scan * fix fmt * Update union_scan.go Recursively close children. * Update union_scan.go Co-authored-by: ti-srebot <[email protected]>
pingcap · Aug 19, 2020 · c15a405 · c15a405
1 parent a113adf
commit c15a405
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diff --git a/executor/union_scan.go b/executor/union_scan.go
@@ -192,6 +192,15 @@ func (us *UnionScanExec) Next(ctx context.Context, req *chunk.Chunk) error {
 	return nil
 }
 
+// Close implements the Executor Close interface.
+func (us *UnionScanExec) Close() error {
+	us.cursor4AddRows = 0
+	us.cursor4SnapshotRows = 0
+	us.addedRows = us.addedRows[:0]
+	us.snapshotRows = us.snapshotRows[:0]
+	return us.children[0].Close()
+}
+
 // getOneRow gets one result row from dirty table or child.
 func (us *UnionScanExec) getOneRow(ctx context.Context) ([]types.Datum, error) {
 	snapshotRow, err := us.getSnapshotRow(ctx)

diff --git a/executor/union_scan_test.go b/executor/union_scan_test.go
@@ -328,3 +328,17 @@ func (s *testSuite7) TestForUpdateUntouchedIndex(c *C) {
 	tk.MustExec("commit")
 	tk.MustExec("admin check table t")
 }
+
+// See https://github.com/pingcap/tidb/issues/19136
+func (s *testSuite7) TestForApplyAndUnionScan(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t")
+
+	tk.MustExec("create table t ( c_int int, c_str varchar(40), primary key(c_int, c_str) )")
+	tk.MustExec("begin")
+	tk.MustExec("insert into t values (1, 'amazing almeida'), (2, 'boring bardeen'), (3, 'busy wescoff')")
+	tk.MustQuery("select c_int, (select t1.c_int from t t1 where t1.c_int = 3 and t1.c_int > t.c_int order by t1.c_int limit 1) x from t").Check(testkit.Rows("1 3", "2 3", "3 <nil>"))
+	tk.MustExec("commit")
+	tk.MustQuery("select c_int, (select t1.c_int from t t1 where t1.c_int = 3 and t1.c_int > t.c_int order by t1.c_int limit 1) x from t").Check(testkit.Rows("1 3", "2 3", "3 <nil>"))
+}