From cec25b3290b0bab28a19c9fc8bbb623a923cc3da Mon Sep 17 00:00:00 2001
From: Haibin Xie <lambdax.tyler@gmail.com>
Date: Wed, 9 Jan 2019 14:31:32 +0800
Subject: [PATCH] resolve schema column index instead

---
 executor/builder.go             | 1 -
 executor/window.go              | 5 ++---
 executor/window_test.go         | 2 ++
 planner/core/physical_plans.go  | 1 -
 planner/core/resolve_indices.go | 6 +++---
 5 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/executor/builder.go b/executor/builder.go
index 1893bab0ebf5f..7a245ca3ebd9d 100644
--- a/executor/builder.go
+++ b/executor/builder.go
@@ -1897,7 +1897,6 @@ func (b *executorBuilder) buildWindow(v *plannercore.PhysicalWindow) *WindowExec
 		windowFunc:    windowFunc,
 		partialResult: windowFunc.AllocPartialResult(),
 		groupChecker:  newGroupChecker(b.ctx.GetSessionVars().StmtCtx, groupByItems),
-		childCols:     v.ChildCols,
 	}
 	return e
 }
diff --git a/executor/window.go b/executor/window.go
index 7c0ddeb8309b1..de615f84a9f30 100644
--- a/executor/window.go
+++ b/executor/window.go
@@ -20,7 +20,6 @@ import (
 	"github.com/opentracing/opentracing-go"
 	"github.com/pingcap/errors"
 	"github.com/pingcap/tidb/executor/windowfuncs"
-	"github.com/pingcap/tidb/expression"
 	"github.com/pingcap/tidb/util/chunk"
 )
 
@@ -36,7 +35,6 @@ type WindowExec struct {
 	windowFunc    windowfuncs.WindowFunc
 	partialResult windowfuncs.PartialResult
 	executed      bool
-	childCols     []*expression.Column
 	meetNewGroup  bool
 }
 
@@ -155,7 +153,8 @@ func (e *WindowExec) copyChk(chk *chunk.Chunk) {
 	}
 	childResult := e.childResults[0]
 	e.childResults = e.childResults[1:]
-	for i, col := range e.childCols {
+	columns := e.Schema().Columns[:len(e.Schema().Columns)-1]
+	for i, col := range columns {
 		chk.CopyColumns(childResult, i, col.Index)
 	}
 }
diff --git a/executor/window_test.go b/executor/window_test.go
index b5a4ae647243a..0e966664add41 100644
--- a/executor/window_test.go
+++ b/executor/window_test.go
@@ -38,4 +38,6 @@ func (s *testSuite2) TestWindowFunctions(c *C) {
 	result.Check(testkit.Rows("8 3", "8 3", "8 3"))
 	result = tk.MustQuery("select sum(t1.a) over() from t t1, t t2")
 	result.Check(testkit.Rows("21", "21", "21", "21", "21", "21", "21", "21", "21"))
+	result = tk.MustQuery("select _tidb_rowid, sum(t.a) over() from t")
+	result.Check(testkit.Rows("1 7", "2 7", "3 7"))
 }
diff --git a/planner/core/physical_plans.go b/planner/core/physical_plans.go
index bb9f6188c2c33..12d829cf3f9d6 100644
--- a/planner/core/physical_plans.go
+++ b/planner/core/physical_plans.go
@@ -383,5 +383,4 @@ type PhysicalWindow struct {
 	WindowFuncDesc *aggregation.WindowFuncDesc
 	PartitionBy    []property.Item
 	OrderBy        []property.Item
-	ChildCols      []*expression.Column
 }
diff --git a/planner/core/resolve_indices.go b/planner/core/resolve_indices.go
index 23c0a3e07bb9f..3145c45f26cdb 100644
--- a/planner/core/resolve_indices.go
+++ b/planner/core/resolve_indices.go
@@ -187,10 +187,10 @@ func (p *PhysicalSort) ResolveIndices() {
 // ResolveIndices implements Plan interface.
 func (p *PhysicalWindow) ResolveIndices() {
 	p.physicalSchemaProducer.ResolveIndices()
-	p.ChildCols = p.Schema().Columns[:len(p.Schema().Columns)-1]
-	for i, col := range p.ChildCols {
+	for i := 0; i < len(p.Schema().Columns)-1; i++ {
+		col := p.Schema().Columns[i]
 		newCol := col.ResolveIndices(p.children[0].Schema())
-		p.ChildCols[i] = newCol.(*expression.Column)
+		p.Schema().Columns[i] = newCol.(*expression.Column)
 	}
 	for i, item := range p.PartitionBy {
 		newCol := item.Col.ResolveIndices(p.children[0].Schema())