executor: use deep copy for maxMin4JSON (#15242)

pingcap · Mar 11, 2020 · 34ff2b9 · 34ff2b9
1 parent fab1c60
commit 34ff2b9
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/executor/aggfuncs/func_max_min.go b/executor/aggfuncs/func_max_min.go
@@ -635,7 +635,7 @@ func (e *maxMin4JSON) UpdatePartialResult(sctx sessionctx.Context, rowsInGroup [
 		}
 		cmp := json.CompareBinary(input, p.val)
 		if e.isMax && cmp > 0 || !e.isMax && cmp < 0 {
-			p.val = input
+			p.val = input.Copy()
 		}
 	}
 	return nil

diff --git a/executor/aggregate_test.go b/executor/aggregate_test.go
@@ -830,3 +830,17 @@ func (s *testSuiteAgg) TestIssue12759HashAggCalledByApply(c *C) {
 		tk.MustQuery(tt).Check(testkit.Rows(output[i]...))
 	}
 }
+
+func (s *testSuiteAgg) TestPR15242ShallowCopy(c *C) {
+	tk := testkit.NewTestKitWithInit(c, s.store)
+	tk.MustExec(`drop table if exists t;`)
+	tk.MustExec(`create table t(a json);`)
+	tk.MustExec(`insert into t values ('{"id": 1,"score":23}');`)
+	tk.MustExec(`insert into t values ('{"id": 2,"score":23}');`)
+	tk.MustExec(`insert into t values ('{"id": 1,"score":233}');`)
+	tk.MustExec(`insert into t values ('{"id": 2,"score":233}');`)
+	tk.MustExec(`insert into t values ('{"id": 3,"score":233}');`)
+	tk.Se.GetSessionVars().MaxChunkSize = 2
+	tk.MustQuery(`select max(JSON_EXTRACT(a, '$.score')) as max_score,JSON_EXTRACT(a,'$.id') as id from t group by id order by id;`).Check(testkit.Rows("233 1", "233 2", "233 3"))
+
+}