Merge pull request #644 from D3Hunter/reuse-buf

Reuse BytesBuffer in BinlogParser

Author: lance6716

replication/parser.go

@@ -11,6 +11,8 @@ import (
 	"time"
 
 	"github.com/pingcap/errors"
+
+	"github.com/go-mysql-org/go-mysql/utils"
 )
 
 var (
@@ -110,8 +112,11 @@ func (p *BinlogParser) parseSingleEvent(r io.Reader, onEvent OnEventFunc) (bool,
 	var err error
 	var n int64
 
-	var buf bytes.Buffer
-	if n, err = io.CopyN(&buf, r, EventHeaderSize); err == io.EOF {
+	// Here we use `sync.Pool` to avoid allocate/destroy buffers frequently.
+	buf := utils.BytesBufferGet()
+	defer utils.BytesBufferPut(buf)
+
+	if n, err = io.CopyN(buf, r, EventHeaderSize); err == io.EOF {
 		return true, nil
 	} else if err != nil {
 		return false, errors.Errorf("get event header err %v, need %d but got %d", err, EventHeaderSize, n)
@@ -126,14 +131,15 @@ func (p *BinlogParser) parseSingleEvent(r io.Reader, onEvent OnEventFunc) (bool,
 	if h.EventSize < uint32(EventHeaderSize) {
 		return false, errors.Errorf("invalid event header, event size is %d, too small", h.EventSize)
 	}
-	if n, err = io.CopyN(&buf, r, int64(h.EventSize-EventHeaderSize)); err != nil {
+	if n, err = io.CopyN(buf, r, int64(h.EventSize-EventHeaderSize)); err != nil {
 		return false, errors.Errorf("get event err %v, need %d but got %d", err, h.EventSize, n)
 	}
 	if buf.Len() != int(h.EventSize) {
 		return false, errors.Errorf("invalid raw data size in event %s, need %d but got %d", h.EventType, h.EventSize, buf.Len())
 	}
 
-	rawData := buf.Bytes()
+	var rawData []byte
+	rawData = append(rawData, buf.Bytes()...)
 	bodyLen := int(h.EventSize) - EventHeaderSize
 	body := rawData[EventHeaderSize:]
 	if len(body) != bodyLen {