remove iterator copy and use back to pre rows

util/chunk/chunk.go

@@ -165,9 +165,9 @@ func (c *Chunk) AppendPartialRows(colIdx int, rowIt Iterator, maxLen int) int {
 	columns := rowIt.Current().c.columns
 	for i, rowCol := range columns {
 		chkCol := c.columns[colIdx+i]
-		rower := rowIt.Copy()
-		if i == len(columns)-1 {
-			rower = rowIt
+		rower := rowIt
+		if i != 0 {
+			rower.PreRows(c.columns[colIdx+0].length - oldRowLen)
 		}
 
 		if rowCol.isFixed() {

util/chunk/chunk_copy_test.go

@@ -93,7 +93,7 @@ func TestCopyColumnByColumn(t *testing.T) {
 
 	dst.Reset()
 	for it1.Begin(); it1.Current() != it1.End(); {
-		dst.AppendRightMultiRows(it1, row, 1024)
+		dst.AppendRightMultiRows(it1, row, 128)
 	}
 	checkDstChk(t, dst)
 }
@@ -120,7 +120,7 @@ func BenchmarkCopyColumnByColumn(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		dst.Reset()
 		for it1.Begin(); it1.Current() != it1.End(); {
-			dst.AppendRightMultiRows(it1, row, 1024)
+			dst.AppendRightMultiRows(it1, row, 128)
 		}
 	}
 }

util/chunk/iterator.go

@@ -32,6 +32,8 @@ type Iterator interface {
 	// Next returns the next Row.
 	Next() Row
 
+	PreRows(i int)
+
 	// End returns the invalid end Row.
 	End() Row
 
@@ -43,8 +45,6 @@ type Iterator interface {
 
 	// ReachEnd reaches the end of iterator.
 	ReachEnd()
-
-	Copy() Iterator
 }
 
 // NewIterator4Slice returns a Iterator for Row slice.
@@ -77,6 +77,11 @@ func (it *iterator4Slice) Next() Row {
 	return row
 }
 
+// PreRows implements the Iterator interface.
+func (it *iterator4Slice) PreRows(i int) {
+
+}
+
 // Current implements the Iterator interface.
 func (it *iterator4Slice) Current() Row {
 	if it.cursor == 0 || it.cursor > it.Len() {
@@ -100,14 +105,6 @@ func (it *iterator4Slice) Len() int {
 	return len(it.rows)
 }
 
-// Copy implements the Iterator interface.
-func (it *iterator4Slice) Copy() Iterator {
-	return &iterator4Slice{
-		rows:   it.rows,
-		cursor: it.cursor,
-	}
-}
-
 // NewIterator4Chunk returns a iterator for Chunk.
 func NewIterator4Chunk(chk *Chunk) *Iterator4Chunk {
 	return &Iterator4Chunk{chk: chk}
@@ -139,6 +136,14 @@ func (it *Iterator4Chunk) Next() Row {
 	return row
 }
 
+// PreRows implements the Iterator interface.
+func (it *Iterator4Chunk) PreRows(i int) {
+	if it.cursor < i {
+		it.Begin()
+	}
+	it.cursor = it.cursor - i
+}
+
 // Current implements the Iterator interface.
 func (it *Iterator4Chunk) Current() Row {
 	if it.cursor == 0 || it.cursor > it.Len() {
@@ -162,14 +167,6 @@ func (it *Iterator4Chunk) Len() int {
 	return it.chk.NumRows()
 }
 
-// Copy implements the Iterator interface.
-func (it *Iterator4Chunk) Copy() Iterator {
-	return &Iterator4Chunk{
-		chk:    it.chk,
-		cursor: it.cursor,
-	}
-}
-
 // NewIterator4List returns a Iterator for List.
 func NewIterator4List(li *List) Iterator {
 	return &iterator4List{li: li}
@@ -214,6 +211,11 @@ func (it *iterator4List) Next() Row {
 	return row
 }
 
+// PreRows implements the Iterator interface.
+func (it *iterator4List) PreRows(i int) {
+
+}
+
 // Current implements the Iterator interface.
 func (it *iterator4List) Current() Row {
 	if (it.chkCursor == 0 && it.rowCursor == 0) || it.chkCursor > it.li.NumChunks() {
@@ -242,15 +244,6 @@ func (it *iterator4List) Len() int {
 	return it.li.Len()
 }
 
-// Copy implements the Iterator interface.
-func (it *iterator4List) Copy() Iterator {
-	return &iterator4List{
-		li:        it.li,
-		chkCursor: it.chkCursor,
-		rowCursor: it.rowCursor,
-	}
-}
-
 // NewIterator4RowPtr returns a Iterator for RowPtrs.
 func NewIterator4RowPtr(li *List, ptrs []RowPtr) Iterator {
 	return &iterator4RowPtr{li: li, ptrs: ptrs}
@@ -282,6 +275,11 @@ func (it *iterator4RowPtr) Next() Row {
 	return row
 }
 
+// PreRows implements the Iterator interface.
+func (it *iterator4RowPtr) PreRows(i int) {
+
+}
+
 // Current implements the Iterator interface.
 func (it *iterator4RowPtr) Current() Row {
 	if it.cursor == 0 || it.cursor > it.Len() {
@@ -304,12 +302,3 @@ func (it *iterator4RowPtr) ReachEnd() {
 func (it *iterator4RowPtr) Len() int {
 	return len(it.ptrs)
 }
-
-// Copy implements the Iterator interface.
-func (it *iterator4RowPtr) Copy() Iterator {
-	return &iterator4RowPtr{
-		li:     it.li,
-		ptrs:   it.ptrs,
-		cursor: it.cursor,
-	}
-}