From 97a9bf8f94b58f204d854af2d6629c094150b0ea Mon Sep 17 00:00:00 2001
From: Ti Chi Robot <ti-community-prow-bot@tidb.io>
Date: Thu, 25 Jan 2024 12:30:21 +0800
Subject: [PATCH] *: memory is not allocated first if the user does not use
 some information from the table. (#50062) (#50171)

close pingcap/tidb#50077
---
 table/tables/tables.go      | 35 +++++++++++++++--------------------
 table/tables/tables_test.go |  6 ------
 tablecodec/tablecodec.go    |  2 +-
 3 files changed, 16 insertions(+), 27 deletions(-)

diff --git a/table/tables/tables.go b/table/tables/tables.go
index a18896ce07f94..082715d571b1c 100644
--- a/table/tables/tables.go
+++ b/table/tables/tables.go
@@ -61,11 +61,11 @@ type TableCommon struct {
 	// physicalTableID is a unique int64 to identify a physical table.
 	physicalTableID                 int64
 	Columns                         []*table.Column
-	PublicColumns                   []*table.Column
-	VisibleColumns                  []*table.Column
-	HiddenColumns                   []*table.Column
-	WritableColumns                 []*table.Column
-	FullHiddenColsAndVisibleColumns []*table.Column
+	publicColumns                   []*table.Column
+	visibleColumns                  []*table.Column
+	hiddenColumns                   []*table.Column
+	writableColumns                 []*table.Column
+	fullHiddenColsAndVisibleColumns []*table.Column
 	indices                         []table.Index
 	meta                            *model.TableInfo
 	allocs                          autoid.Allocators
@@ -169,11 +169,6 @@ func initTableCommon(t *TableCommon, tblInfo *model.TableInfo, physicalTableID i
 	t.allocs = allocs
 	t.meta = tblInfo
 	t.Columns = cols
-	t.PublicColumns = t.Cols()
-	t.VisibleColumns = t.VisibleCols()
-	t.HiddenColumns = t.HiddenCols()
-	t.WritableColumns = t.WritableCols()
-	t.FullHiddenColsAndVisibleColumns = t.FullHiddenColsAndVisibleCols()
 	t.recordPrefix = tablecodec.GenTableRecordPrefix(physicalTableID)
 	t.indexPrefix = tablecodec.GenTableIndexPrefix(physicalTableID)
 	if tblInfo.IsSequence() {
@@ -260,32 +255,32 @@ func (t *TableCommon) getCols(mode getColsMode) []*table.Column {
 
 // Cols implements table.Table Cols interface.
 func (t *TableCommon) Cols() []*table.Column {
-	if len(t.PublicColumns) > 0 {
-		return t.PublicColumns
+	if len(t.publicColumns) > 0 {
+		return t.publicColumns
 	}
 	return t.getCols(full)
 }
 
 // VisibleCols implements table.Table VisibleCols interface.
 func (t *TableCommon) VisibleCols() []*table.Column {
-	if len(t.VisibleColumns) > 0 {
-		return t.VisibleColumns
+	if len(t.visibleColumns) > 0 {
+		return t.visibleColumns
 	}
 	return t.getCols(visible)
 }
 
 // HiddenCols implements table.Table HiddenCols interface.
 func (t *TableCommon) HiddenCols() []*table.Column {
-	if len(t.HiddenColumns) > 0 {
-		return t.HiddenColumns
+	if len(t.hiddenColumns) > 0 {
+		return t.hiddenColumns
 	}
 	return t.getCols(hidden)
 }
 
 // WritableCols implements table WritableCols interface.
 func (t *TableCommon) WritableCols() []*table.Column {
-	if len(t.WritableColumns) > 0 {
-		return t.WritableColumns
+	if len(t.writableColumns) > 0 {
+		return t.writableColumns
 	}
 	writableColumns := make([]*table.Column, 0, len(t.Columns))
 	for _, col := range t.Columns {
@@ -304,8 +299,8 @@ func (t *TableCommon) DeletableCols() []*table.Column {
 
 // FullHiddenColsAndVisibleCols implements table FullHiddenColsAndVisibleCols interface.
 func (t *TableCommon) FullHiddenColsAndVisibleCols() []*table.Column {
-	if len(t.FullHiddenColsAndVisibleColumns) > 0 {
-		return t.FullHiddenColsAndVisibleColumns
+	if len(t.fullHiddenColsAndVisibleColumns) > 0 {
+		return t.fullHiddenColsAndVisibleColumns
 	}
 
 	cols := make([]*table.Column, 0, len(t.Columns))
diff --git a/table/tables/tables_test.go b/table/tables/tables_test.go
index 661770b868383..28502e75e57e8 100644
--- a/table/tables/tables_test.go
+++ b/table/tables/tables_test.go
@@ -449,12 +449,6 @@ func TestHiddenColumn(t *testing.T) {
 	colInfo[1].Hidden = true
 	colInfo[3].Hidden = true
 	colInfo[5].Hidden = true
-	tc := tb.(*tables.TableCommon)
-	// Reset related caches
-	tc.VisibleColumns = nil
-	tc.WritableColumns = nil
-	tc.HiddenColumns = nil
-	tc.FullHiddenColsAndVisibleColumns = nil
 
 	// Basic test
 	cols := tb.VisibleCols()
diff --git a/tablecodec/tablecodec.go b/tablecodec/tablecodec.go
index 022caefaa9ec4..8766b188d9164 100644
--- a/tablecodec/tablecodec.go
+++ b/tablecodec/tablecodec.go
@@ -958,7 +958,7 @@ func decodeIntHandleInIndexValue(data []byte) kv.Handle {
 
 // EncodeTableIndexPrefix encodes index prefix with tableID and idxID.
 func EncodeTableIndexPrefix(tableID, idxID int64) kv.Key {
-	key := make([]byte, 0, prefixLen)
+	key := make([]byte, 0, prefixLen+idLen)
 	key = appendTableIndexPrefix(key, tableID)
 	key = codec.EncodeInt(key, idxID)
 	return key