From 89a95dcf70c4309fdf4603e737a77b8812ad85d6 Mon Sep 17 00:00:00 2001
From: Yiding Cui <winoros@gmail.com>
Date: Wed, 15 Jul 2020 02:57:34 +0800
Subject: [PATCH] planner: don't put the handle column twice into the index
 column

---
 executor/join_test.go         | 11 +++++++++++
 planner/core/logical_plans.go | 13 +++++++++++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/executor/join_test.go b/executor/join_test.go
index 86577c42dc9e3..bedd4572d4ab4 100644
--- a/executor/join_test.go
+++ b/executor/join_test.go
@@ -2090,3 +2090,14 @@ func (s *testSuiteJoinSerial) TestIssue18070(c *C) {
 	err = tk.QueryToErr("select /*+ inl_merge_join(t1)*/ * from t1 join t2 on t1.a = t2.a;")
 	c.Assert(strings.Contains(err.Error(), "Out Of Memory Quota!"), IsTrue)
 }
+
+func (s *testSuiteJoin1) TestIssue18564(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t1, t2")
+	tk.MustExec("create table t1(a int, b int, primary key(a), index idx(b,a));")
+	tk.MustExec("create table t2(a int, b int, primary key(a), index idx(b,a));")
+	tk.MustExec("insert into t1 values(1, 1)")
+	tk.MustExec("insert into t2 values(1, 1)")
+	tk.MustQuery("select /*+ INL_JOIN(t1) */ * from t1 FORCE INDEX (idx) join t2 on t1.b=t2.b and t1.a = t2.a").Check(testkit.Rows("1 1 1 1"))
+}
diff --git a/planner/core/logical_plans.go b/planner/core/logical_plans.go
index 7a9e49ff4e999..cd77af26c8d7c 100644
--- a/planner/core/logical_plans.go
+++ b/planner/core/logical_plans.go
@@ -813,8 +813,17 @@ func (ds *DataSource) fillIndexPath(path *util.AccessPath, conds []expression.Ex
 	if !path.Index.Unique && !path.Index.Primary && len(path.Index.Columns) == len(path.IdxCols) {
 		handleCol := ds.getPKIsHandleCol()
 		if handleCol != nil && !mysql.HasUnsignedFlag(handleCol.RetType.Flag) {
-			path.IdxCols = append(path.IdxCols, handleCol)
-			path.IdxColLens = append(path.IdxColLens, types.UnspecifiedLength)
+			alreadyHandle := false
+			for _, col := range path.IdxCols {
+				if col.ID == model.ExtraHandleID || col.Equal(nil, handleCol) {
+					alreadyHandle = true
+				}
+			}
+			// Don't add one column twice to the index. May cause unexpected errors.
+			if !alreadyHandle {
+				path.IdxCols = append(path.IdxCols, handleCol)
+				path.IdxColLens = append(path.IdxColLens, types.UnspecifiedLength)
+			}
 		}
 	}
 	if len(path.IdxCols) != 0 {