Performance Improvement in tds and ucs2 parsing - V1-Candidate (#14)

* Perf improfement tds and decoding ucs2 strings

* Reduce pooled buffer size

* fix unit test expected value message

* fix typo in comment

* fix linting issues

buf.go

@@ -4,6 +4,7 @@ import (
 	"encoding/binary"
 	"errors"
 	"io"
+	"sync"
 )
 
 type packetType uint8
@@ -17,6 +18,16 @@ type header struct {
 	Pad        uint8
 }
 
+// bufpool provides buffers which are used for reading and writing in the tdsBuffer instances
+var bufpool = sync.Pool{
+	New: func() interface{} {
+		b := make([]byte, 1<<16)
+		// If the return value is not a pointer, any conversion from interface{} will
+		// involve an allocation.
+		return &b
+	},
+}
+
 // tdsBuffer reads and writes TDS packets of data to the transport.
 // The write and read buffers are separate to make sending attn signals
 // possible without locks. Currently attn signals are only sent during
@@ -26,6 +37,9 @@ type tdsBuffer struct {
 
 	packetSize int
 
+	// bufClose is responsible for returning the buffer back to the pool
+	bufClose func()
+
 	// Write fields.
 	wbuf        []byte
 	wpos        int
@@ -46,10 +60,15 @@ type tdsBuffer struct {
 }
 
 func newTdsBuffer(bufsize uint16, transport io.ReadWriteCloser) *tdsBuffer {
+
+	// pull an existing buf if one is available or get and add a new buf to the bufpool
+	buf := bufpool.Get().(*[]byte)
+
 	return &tdsBuffer{
 		packetSize: int(bufsize),
-		wbuf:       make([]byte, bufsize),
-		rbuf:       make([]byte, bufsize),
+		wbuf:       (*buf)[:1<<15],
+		rbuf:       (*buf)[1<<15:],
+		bufClose:   func() { bufpool.Put(buf) },
 		rpos:       8,
 		transport:  transport,
 	}
@@ -201,32 +220,57 @@ func (r *tdsBuffer) byte() byte {
 }
 
 func (r *tdsBuffer) ReadFull(buf []byte) {
-	_, err := io.ReadFull(r, buf[:])
+	_, err := io.ReadFull(r, buf)
 	if err != nil {
 		badStreamPanic(err)
 	}
 }
 
 func (r *tdsBuffer) uint64() uint64 {
-	var buf [8]byte
-	r.ReadFull(buf[:])
-	return binary.LittleEndian.Uint64(buf[:])
+	// have we got enough room in the buffer to read 8 bytes, if not, do a ReadFull, else read directly from r.rbuf
+	if r.rpos+7 >= r.rsize {
+		var buf [8]byte
+		r.ReadFull(buf[:])
+
+		return uint64(buf[0]) | uint64(buf[1])<<8 | uint64(buf[2])<<16 | uint64(buf[3])<<24 |
+			uint64(buf[4])<<32 | uint64(buf[5])<<40 | uint64(buf[6])<<48 | uint64(buf[7])<<56
+	}
+
+	res := uint64(r.rbuf[r.rpos]) | uint64(r.rbuf[r.rpos+1])<<8 | uint64(r.rbuf[r.rpos+2])<<16 | uint64(r.rbuf[r.rpos+3])<<24 |
+		uint64(r.rbuf[r.rpos+4])<<32 | uint64(r.rbuf[r.rpos+5])<<40 | uint64(r.rbuf[r.rpos+6])<<48 | uint64(r.rbuf[r.rpos+7])<<56
+
+	r.rpos += 8
+	return res
 }
 
 func (r *tdsBuffer) int32() int32 {
 	return int32(r.uint32())
 }
 
 func (r *tdsBuffer) uint32() uint32 {
-	var buf [4]byte
-	r.ReadFull(buf[:])
-	return binary.LittleEndian.Uint32(buf[:])
+	// have we got enough room in the buffer to read 4 bytes, if not, do a ReadFull, else read directly from r.rbuf
+	if r.rpos+3 >= r.rsize {
+		var buf [4]byte
+		r.ReadFull(buf[:])
+		return uint32(buf[0]) | uint32(buf[1])<<8 | uint32(buf[2])<<16 | uint32(buf[3])<<24
+	}
+
+	res := uint32(r.rbuf[r.rpos]) | uint32(r.rbuf[r.rpos+1])<<8 | uint32(r.rbuf[r.rpos+2])<<16 | uint32(r.rbuf[r.rpos+3])<<24
+	r.rpos += 4
+	return res
 }
 
 func (r *tdsBuffer) uint16() uint16 {
-	var buf [2]byte
-	r.ReadFull(buf[:])
-	return binary.LittleEndian.Uint16(buf[:])
+	// have we got enough room in the buffer to read 2 bytes, if not, do a ReadFull, else read directly from r.rbuf
+	if r.rpos+1 >= r.rsize {
+		var buf [2]byte
+		r.ReadFull(buf[:])
+		return uint16(buf[0]) | uint16(buf[1])<<8
+	}
+
+	res := uint16(r.rbuf[r.rpos]) | uint16(r.rbuf[r.rpos+1])<<8
+	r.rpos += 2
+	return res
 }
 
 func (r *tdsBuffer) BVarChar() string {

buf_test.go

@@ -2,8 +2,10 @@ package mssql
 
 import (
 	"bytes"
+	"encoding/binary"
 	"errors"
 	"testing"
+	"unicode/utf16"
 )
 
 type closableBuffer struct {
@@ -118,6 +120,165 @@ func TestBeginReadSucceeds(t *testing.T) {
 	}
 }
 
+func makeLargeDataBuffer() []byte {
+	data := make([]byte, 1<<15)
+
+	for i := 0; i < len(data); i += 4 {
+		data[i] = 0xFE
+		data[i+1] = 0xDC
+		data[i+2] = 0xBA
+		data[i+3] = 0x89
+	}
+
+	return data
+}
+
+func TestReadUint16Succeeds(t *testing.T) {
+
+	data := makeLargeDataBuffer()
+	size := 0x9 + (1 << 14)
+	buffer := makeBuf(uint16(size), append([]byte{0x01 /*id*/, 0xFF /*status*/, byte((size >> 8) & 0xFF), byte(size & 0xFF) /*size*/, 0xff, 0xff, 0xff, 0xff, 0xff /* byte pattern data to follow */}, data...))
+
+	id, err := buffer.BeginRead()
+	if err != nil {
+		t.Fatal("BeginRead failed:", err.Error())
+	}
+	if id != 1 {
+		t.Fatalf("Expected id to be 1 but it is %d", id)
+	}
+
+	buffer.byte()
+
+	iterations := 0
+
+	defer func() {
+
+		if iterations != (1<<14)/4 {
+			t.Fatalf("Expected to read all data, but only read %v", iterations*4)
+		}
+
+		v := recover()
+		if v == nil {
+			t.Fatalf("Expected EOF but got nil")
+		}
+
+		if err, ok := v.(error); ok {
+			if err.Error() != "Invalid TDS stream: EOF" {
+				t.Fatalf("Expected EOF but got %v", err)
+			}
+		} else {
+			t.Fatalf("Expected EOF but got %v", v)
+		}
+	}()
+
+	for {
+
+		a := buffer.uint16()
+		if a != 0xdcfe {
+			t.Fatalf("Expected read uint16 to be 0xfedc but it is %d", a)
+		}
+
+		b := buffer.uint16()
+		if b != 0x89ba {
+			t.Fatalf("Expected read uint16 to be 0x89ba but it is %d", a)
+		}
+
+		iterations++
+	}
+
+}
+
+func TestReadUint32Succeeds(t *testing.T) {
+
+	data := makeLargeDataBuffer()
+	size := 0x9 + (1 << 14)
+	buffer := makeBuf(uint16(size), append([]byte{0x01 /*id*/, 0xFF /*status*/, byte((size >> 8) & 0xFF), byte(size & 0xFF) /*size*/, 0xff, 0xff, 0xff, 0xff, 0xff /* byte pattern data to follow */}, data...))
+
+	id, err := buffer.BeginRead()
+	if err != nil {
+		t.Fatal("BeginRead failed:", err.Error())
+	}
+	if id != 1 {
+		t.Fatalf("Expected id to be 1 but it is %d", id)
+	}
+
+	buffer.byte()
+
+	iterations := 0
+	defer func() {
+		if iterations != (1<<14)/4 {
+			t.Fatalf("Expected to read all data, but only read %v", iterations*4)
+		}
+
+		v := recover()
+		if v == nil {
+			t.Fatalf("Expected EOF but got nil")
+		}
+
+		if err, ok := v.(error); ok {
+			if err.Error() != "Invalid TDS stream: EOF" {
+				t.Fatalf("Expected EOF but got %v", err)
+			}
+		} else {
+			t.Fatalf("Expected EOF but got %v", v)
+		}
+	}()
+	for {
+		a := buffer.uint32()
+		if a != 0x89badcfe {
+			t.Fatalf("Expected read uint16 to be 0x89badcfe but it is %d", a)
+		}
+
+		iterations++
+	}
+}
+
+func TestReadUint64Succeeds(t *testing.T) {
+
+	data := makeLargeDataBuffer()
+	size := 0x9 + (1 << 14)
+	buffer := makeBuf(uint16(size), append([]byte{0x01 /*id*/, 0xFF /*status*/, byte((size >> 8) & 0xFF), byte(size & 0xFF) /*size*/, 0xff, 0xff, 0xff, 0xff, 0xff /* byte pattern data to follow */}, data...))
+
+	id, err := buffer.BeginRead()
+	if err != nil {
+		t.Fatal("BeginRead failed:", err.Error())
+	}
+	if id != 1 {
+		t.Fatalf("Expected id to be 1 but it is %d", id)
+	}
+
+	buffer.byte()
+
+	iterations := 0
+	defer func() {
+		if iterations != (1<<14)/8 {
+			t.Fatalf("Expected to read all data, but only read %v", iterations*4)
+		}
+
+		v := recover()
+		if v == nil {
+			t.Fatalf("Expected EOF but got nil")
+		}
+
+		if err, ok := v.(error); ok {
+			if err.Error() != "Invalid TDS stream: EOF" {
+				t.Fatalf("Expected EOF but got %v", err)
+			}
+		} else {
+			t.Fatalf("Expected EOF but got %v", v)
+		}
+	}()
+
+	for {
+		a := buffer.uint64()
+		if a != 0x89badcfe89badcfe {
+			t.Fatalf("Expected read uint16 to be 0x89badcfe89badcfe but it is %d", a)
+		}
+
+		iterations++
+	}
+}
+
 func TestReadByteFailsOnSecondPacket(t *testing.T) {
 	buffer := makeBuf(9, []byte{
 		0x01 /*id*/, 0x0 /*not final*/, 0x0, 0x9 /*size*/, 0xff, 0xff, 0xff, 0xff, 0x02, /*test byte*/
@@ -299,6 +460,88 @@ func TestReadUsVarCharOrPanic(t *testing.T) {
 	t.Fatal("UsVarChar() should panic, but it didn't")
 }
 
+func TestReadUsVarCharOrPanicWideChars(t *testing.T) {
+	str := "百度一下，你就知道"
+	runes := utf16.Encode([]rune(str))
+	encodedBytes := make([]byte, len(runes)*2)
+
+	for i := 0; i < len(runes); i++ {
+		binary.LittleEndian.PutUint16(encodedBytes[i*2:], runes[i])
+	}
+
+	memBuf := bytes.NewBuffer(append([]byte{byte(len(runes)), 0}, encodedBytes...))
+
+	s := readUsVarCharOrPanic(memBuf)
+	if s != str {
+		t.Errorf("UsVarChar expected to return %s but it returned %s", str, s)
+	}
+}
+
+func TestReadBVarCharOrPanicWideChars(t *testing.T) {
+	str := "百度一下，你就知道"
+	runes := utf16.Encode([]rune(str))
+	encodedBytes := make([]byte, len(runes)*2)
+
+	for i := 0; i < len(runes); i++ {
+		binary.LittleEndian.PutUint16(encodedBytes[i*2:], runes[i])
+	}
+
+	memBuf := bytes.NewBuffer(append([]byte{byte(len(runes))}, encodedBytes...))
+
+	s := readBVarCharOrPanic(memBuf)
+	if s != str {
+		t.Errorf("UsVarChar expected to return %s but it returned %s", str, s)
+	}
+}
+
+var sideeffectstring string
+
+func BenchmarkReadBVarCharOrPanicWideChars(b *testing.B) {
+	str := "百度一下，你就知道"
+
+	runes := utf16.Encode([]rune(str))
+	encodedBytes := make([]byte, len(runes)*2)
+
+	for i := 0; i < len(runes); i++ {
+		binary.LittleEndian.PutUint16(encodedBytes[i*2:], runes[i])
+	}
+
+	encodedBytes = append([]byte{byte(len(runes))}, encodedBytes...)
+
+	memBuf := bytes.NewReader(encodedBytes)
+
+	for n := 0; n < b.N; n++ {
+
+		s := readBVarCharOrPanic(memBuf)
+		sideeffectstring = s
+
+		memBuf.Reset(encodedBytes)
+	}
+}
+
+func BenchmarkReadBVarCharOrPanicOnly1WideChar(b *testing.B) {
+	str := "abcdefghijklmno百p"
+
+	runes := utf16.Encode([]rune(str))
+	encodedBytes := make([]byte, len(runes)*2)
+
+	for i := 0; i < len(runes); i++ {
+		binary.LittleEndian.PutUint16(encodedBytes[i*2:], runes[i])
+	}
+
+	encodedBytes = append([]byte{byte(len(runes))}, encodedBytes...)
+
+	memBuf := bytes.NewReader(encodedBytes)
+
+	for n := 0; n < b.N; n++ {
+
+		s := readBVarCharOrPanic(memBuf)
+		sideeffectstring = s
+
+		memBuf.Reset(encodedBytes)
+	}
+}
+
 func TestReadBVarCharOrPanic(t *testing.T) {
 	memBuf := bytes.NewBuffer([]byte{3, 0x31, 0, 0x32, 0, 0x33, 0})
 	s := readBVarCharOrPanic(memBuf)

mssql.go

@@ -428,6 +428,7 @@ func (d *Driver) connect(ctx context.Context, c *Connector, params msdsn.Config)
 }
 
 func (c *Conn) Close() error {
+	c.sess.buf.bufClose()
 	return c.sess.buf.transport.Close()
 }