diff --git a/util/chunk/chunk.go b/util/chunk/chunk.go
index a4350bd9628e3..e91cff2559d79 100644
--- a/util/chunk/chunk.go
+++ b/util/chunk/chunk.go
@@ -505,8 +505,10 @@ func (c *Chunk) Append(other *Chunk, begin, end int) {
 		} else {
 			beginOffset, endOffset := src.offsets[begin], src.offsets[end]
 			dst.data = append(dst.data, src.data[beginOffset:endOffset]...)
+			lastOffset := dst.offsets[len(dst.offsets)-1]
 			for i := begin; i < end; i++ {
-				dst.offsets = append(dst.offsets, dst.offsets[len(dst.offsets)-1]+src.offsets[i+1]-src.offsets[i])
+				lastOffset += src.offsets[i+1] - src.offsets[i]
+				dst.offsets = append(dst.offsets, lastOffset)
 			}
 		}
 		for i := begin; i < end; i++ {
diff --git a/util/chunk/chunk_test.go b/util/chunk/chunk_test.go
index 67222328794db..22a6ac5b473dc 100644
--- a/util/chunk/chunk_test.go
+++ b/util/chunk/chunk_test.go
@@ -1179,3 +1179,80 @@ func BenchmarkBatchAppendRows(b *testing.B) {
 		})
 	}
 }
+
+func BenchmarkAppendRows(b *testing.B) {
+	b.ReportAllocs()
+	rowChk := newChunk(8, 8, 0, 0)
+
+	for i := 0; i < 4096; i++ {
+		rowChk.AppendNull(0)
+		rowChk.AppendInt64(1, 1)
+		rowChk.AppendString(2, "abcd")
+		rowChk.AppendBytes(3, []byte("abcd"))
+	}
+
+	type testCaseConf struct {
+		batchSize int
+	}
+	testCaseConfs := []testCaseConf{
+		{batchSize: 2},
+		{batchSize: 8},
+		{batchSize: 16},
+		{batchSize: 100},
+		{batchSize: 1000},
+		{batchSize: 4000},
+	}
+
+	chk := newChunk(8, 8, 0, 0)
+	for _, conf := range testCaseConfs {
+		b.ResetTimer()
+		b.Run(fmt.Sprintf("row-%d", conf.batchSize), func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				chk.Reset()
+				for j := 0; j < conf.batchSize; j++ {
+					chk.AppendRow(rowChk.GetRow(j))
+				}
+			}
+		})
+		b.ResetTimer()
+		b.Run(fmt.Sprintf("column-%d", conf.batchSize), func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				chk.Reset()
+				chk.Append(rowChk, 0, conf.batchSize)
+			}
+		})
+	}
+}
+
+func BenchmarkAppend(b *testing.B) {
+	b.ReportAllocs()
+	rowChk := newChunk(0, 0)
+
+	for i := 0; i < 4096; i++ {
+		rowChk.AppendString(0, "abcd")
+		rowChk.AppendBytes(1, []byte("abcd"))
+	}
+
+	type testCaseConf struct {
+		batchSize int
+	}
+	testCaseConfs := []testCaseConf{
+		{batchSize: 2},
+		{batchSize: 8},
+		{batchSize: 16},
+		{batchSize: 100},
+		{batchSize: 1000},
+		{batchSize: 4000},
+	}
+
+	chk := newChunk(0, 0)
+	for _, conf := range testCaseConfs {
+		b.ResetTimer()
+		b.Run(fmt.Sprintf("column-%d", conf.batchSize), func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				chk.Reset()
+				chk.Append(rowChk, 0, conf.batchSize)
+			}
+		})
+	}
+}