allow packet.Conn buffersize to be adjustable (#892)

client/auth.go

@@ -304,7 +304,7 @@ func (c *Conn) writeAuthHandshake() error {
 		}
 
 		currentSequence := c.Sequence
-		c.Conn = packet.NewConn(tlsConn)
+		c.Conn = packet.NewBufferedConn(tlsConn, c.BufferSize)
 		c.Sequence = currentSequence
 	}
 

client/conn.go

@@ -18,6 +18,8 @@ import (
 	"github.com/go-mysql-org/go-mysql/utils"
 )
 
+const defaultBufferSize = 65536 // 64kb
+
 type Option func(*Conn) error
 
 type Conn struct {
@@ -33,6 +35,9 @@ type Conn struct {
 	ReadTimeout  time.Duration
 	WriteTimeout time.Duration
 
+	// The buffer size to use in the packet connection
+	BufferSize int
+
 	serverVersion string
 	// server capabilities
 	capability uint32
@@ -94,6 +99,7 @@ type Dialer func(ctx context.Context, network, address string) (net.Conn, error)
 func ConnectWithDialer(ctx context.Context, network, addr, user, password, dbName string, dialer Dialer, options ...Option) (*Conn, error) {
 	c := new(Conn)
 
+	c.BufferSize = defaultBufferSize
 	c.attributes = map[string]string{
 		"_client_name": "go-mysql",
 		// "_client_version": "0.1",
@@ -129,7 +135,7 @@ func ConnectWithDialer(ctx context.Context, network, addr, user, password, dbNam
 		}
 	}
 
-	c.Conn = packet.NewConnWithTimeout(conn, c.ReadTimeout, c.WriteTimeout)
+	c.Conn = packet.NewConnWithTimeout(conn, c.ReadTimeout, c.WriteTimeout, c.BufferSize)
 	if c.tlsConfig != nil {
 		seq := c.Conn.Sequence
 		c.Conn = packet.NewTLSConnWithTimeout(conn, c.ReadTimeout, c.WriteTimeout)

driver/driver_options_test.go

@@ -8,6 +8,7 @@ import (
 	"math"
 	"net"
 	"reflect"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
@@ -73,6 +74,29 @@ func TestDriverOptions_ConnectTimeout(t *testing.T) {
 	conn.Close()
 }
 
+func TestDriverOptions_BufferSize(t *testing.T) {
+	log.SetLevel(log.LevelDebug)
+	srv := CreateMockServer(t)
+	defer srv.Stop()
+
+	SetDSNOptions(map[string]DriverOption{
+		"bufferSize": func(c *client.Conn, value string) error {
+			var err error
+			c.BufferSize, err = strconv.Atoi(value)
+			return err
+		},
+	})
+
+	conn, err := sql.Open("mysql", "[email protected]:3307/test?bufferSize=4096")
+	require.NoError(t, err)
+
+	rows, err := conn.QueryContext(context.TODO(), "select * from table;")
+	require.NotNil(t, rows)
+	require.NoError(t, err)
+
+	conn.Close()
+}
+
 func TestDriverOptions_ReadTimeout(t *testing.T) {
 	log.SetLevel(log.LevelDebug)
 	srv := CreateMockServer(t)

packet/conn.go

@@ -53,19 +53,23 @@ type Conn struct {
 }
 
 func NewConn(conn net.Conn) *Conn {
+	return NewBufferedConn(conn, 65536) // 64kb
+}
+
+func NewBufferedConn(conn net.Conn, bufferSize int) *Conn {
 	c := new(Conn)
 	c.Conn = conn
 
-	c.br = bufio.NewReaderSize(c, 65536) // 64kb
+	c.br = bufio.NewReaderSize(c, bufferSize)
 	c.reader = c.br
 
 	c.copyNBuf = make([]byte, DefaultBufferSize)
 
 	return c
 }
 
-func NewConnWithTimeout(conn net.Conn, readTimeout, writeTimeout time.Duration) *Conn {
-	c := NewConn(conn)
+func NewConnWithTimeout(conn net.Conn, readTimeout, writeTimeout time.Duration, bufferSize int) *Conn {
+	c := NewBufferedConn(conn, bufferSize)
 	c.readTimeout = readTimeout
 	c.writeTimeout = writeTimeout
 	return c