add configurable buffer sizes for Redis connections

Author: ofekshenawa

README.md

@@ -297,6 +297,18 @@ func main() {
 ```
 
 
+### Buffer Size Configuration
+
+go-redis uses 0.5MiB read and write buffers by default for optimal performance. For high-throughput applications or large pipelines, you can customize buffer sizes:
+
+```go
+rdb := redis.NewClient(&redis.Options{
+    Addr:            "localhost:6379",
+    ReadBufferSize:  1024 * 1024, // 1MiB read buffer
+    WriteBufferSize: 1024 * 1024, // 1MiB write buffer
+})
+```
+
 ### Advanced Configuration
 
 go-redis supports extending the client identification phase to allow projects to send their own custom client identification.

internal/pool/buffer_size_test.go

@@ -0,0 +1,183 @@
+package pool_test
+
+import (
+	"bufio"
+	"context"
+	"net"
+	"unsafe"
+
+	. "github.com/bsm/ginkgo/v2"
+	. "github.com/bsm/gomega"
+
+	"github.com/redis/go-redis/v9/internal/pool"
+	"github.com/redis/go-redis/v9/internal/proto"
+)
+
+var _ = Describe("Buffer Size Configuration", func() {
+	var connPool *pool.ConnPool
+	ctx := context.Background()
+
+	AfterEach(func() {
+		if connPool != nil {
+			connPool.Close()
+		}
+	})
+
+	It("should use default buffer sizes when not specified", func() {
+		connPool = pool.NewConnPool(&pool.Options{
+			Dialer:      dummyDialer,
+			PoolSize:    1,
+			PoolTimeout: 1000,
+		})
+
+		cn, err := connPool.NewConn(ctx)
+		Expect(err).NotTo(HaveOccurred())
+		defer connPool.CloseConn(cn)
+
+		// Check that default buffer sizes are used (0.5MiB)
+		writerBufSize := getWriterBufSizeUnsafe(cn)
+		readerBufSize := getReaderBufSizeUnsafe(cn)
+
+		Expect(writerBufSize).To(Equal(proto.DefaultBufferSize)) // Default 0.5MiB buffer size
+		Expect(readerBufSize).To(Equal(proto.DefaultBufferSize)) // Default 0.5MiB buffer size
+	})
+
+	It("should use custom buffer sizes when specified", func() {
+		customReadSize := 32 * 1024  // 32KB
+		customWriteSize := 64 * 1024 // 64KB
+
+		connPool = pool.NewConnPool(&pool.Options{
+			Dialer:          dummyDialer,
+			PoolSize:        1,
+			PoolTimeout:     1000,
+			ReadBufferSize:  customReadSize,
+			WriteBufferSize: customWriteSize,
+		})
+
+		cn, err := connPool.NewConn(ctx)
+		Expect(err).NotTo(HaveOccurred())
+		defer connPool.CloseConn(cn)
+
+		// Check that custom buffer sizes are used
+		writerBufSize := getWriterBufSizeUnsafe(cn)
+		readerBufSize := getReaderBufSizeUnsafe(cn)
+
+		Expect(writerBufSize).To(Equal(customWriteSize))
+		Expect(readerBufSize).To(Equal(customReadSize))
+	})
+
+	It("should handle zero buffer sizes by using defaults", func() {
+		connPool = pool.NewConnPool(&pool.Options{
+			Dialer:          dummyDialer,
+			PoolSize:        1,
+			PoolTimeout:     1000,
+			ReadBufferSize:  0, // Should use default
+			WriteBufferSize: 0, // Should use default
+		})
+
+		cn, err := connPool.NewConn(ctx)
+		Expect(err).NotTo(HaveOccurred())
+		defer connPool.CloseConn(cn)
+
+		// Check that default buffer sizes are used (0.5MiB)
+		writerBufSize := getWriterBufSizeUnsafe(cn)
+		readerBufSize := getReaderBufSizeUnsafe(cn)
+
+		Expect(writerBufSize).To(Equal(proto.DefaultBufferSize)) // Default 0.5MiB buffer size
+		Expect(readerBufSize).To(Equal(proto.DefaultBufferSize)) // Default 0.5MiB buffer size
+	})
+
+	It("should use 0.5MiB default buffer sizes for standalone NewConn", func() {
+		// Test that NewConn (without pool) also uses 0.5MiB defaults
+		netConn := newDummyConn()
+		cn := pool.NewConn(netConn)
+		defer cn.Close()
+
+		writerBufSize := getWriterBufSizeUnsafe(cn)
+		readerBufSize := getReaderBufSizeUnsafe(cn)
+
+		Expect(writerBufSize).To(Equal(proto.DefaultBufferSize)) // Default 0.5MiB buffer size
+		Expect(readerBufSize).To(Equal(proto.DefaultBufferSize)) // Default 0.5MiB buffer size
+	})
+
+	It("should use 0.5MiB defaults even when pool is created directly without buffer sizes", func() {
+		// Test the scenario where someone creates a pool directly (like in tests)
+		// without setting ReadBufferSize and WriteBufferSize
+		connPool = pool.NewConnPool(&pool.Options{
+			Dialer:      dummyDialer,
+			PoolSize:    1,
+			PoolTimeout: 1000,
+			// ReadBufferSize and WriteBufferSize are not set (will be 0)
+		})
+
+		cn, err := connPool.NewConn(ctx)
+		Expect(err).NotTo(HaveOccurred())
+		defer connPool.CloseConn(cn)
+
+		// Should still get 0.5MiB defaults because NewConnPool sets them
+		writerBufSize := getWriterBufSizeUnsafe(cn)
+		readerBufSize := getReaderBufSizeUnsafe(cn)
+
+		Expect(writerBufSize).To(Equal(proto.DefaultBufferSize)) // Default 0.5MiB buffer size
+		Expect(readerBufSize).To(Equal(proto.DefaultBufferSize)) // Default 0.5MiB buffer size
+	})
+})
+
+// Helper functions to extract buffer sizes using unsafe pointers
+func getWriterBufSizeUnsafe(cn *pool.Conn) int {
+	cnPtr := (*struct {
+		usedAt  int64
+		netConn net.Conn
+		rd      *proto.Reader
+		bw      *bufio.Writer
+		wr      *proto.Writer
+		// ... other fields
+	})(unsafe.Pointer(cn))
+
+	if cnPtr.bw == nil {
+		return -1
+	}
+
+	bwPtr := (*struct {
+		err error
+		buf []byte
+		n   int
+		wr  interface{}
+	})(unsafe.Pointer(cnPtr.bw))
+
+	return len(bwPtr.buf)
+}
+
+func getReaderBufSizeUnsafe(cn *pool.Conn) int {
+	cnPtr := (*struct {
+		usedAt  int64
+		netConn net.Conn
+		rd      *proto.Reader
+		bw      *bufio.Writer
+		wr      *proto.Writer
+		// ... other fields
+	})(unsafe.Pointer(cn))
+
+	if cnPtr.rd == nil {
+		return -1
+	}
+
+	rdPtr := (*struct {
+		rd *bufio.Reader
+	})(unsafe.Pointer(cnPtr.rd))
+
+	if rdPtr.rd == nil {
+		return -1
+	}
+
+	bufReaderPtr := (*struct {
+		buf          []byte
+		rd           interface{}
+		r, w         int
+		err          error
+		lastByte     int
+		lastRuneSize int
+	})(unsafe.Pointer(rdPtr.rd))
+
+	return len(bufReaderPtr.buf)
+}

internal/pool/conn.go

@@ -28,12 +28,28 @@ type Conn struct {
 }
 
 func NewConn(netConn net.Conn) *Conn {
+	return NewConnWithBufferSize(netConn, proto.DefaultBufferSize, proto.DefaultBufferSize)
+}
+
+func NewConnWithBufferSize(netConn net.Conn, readBufSize, writeBufSize int) *Conn {
 	cn := &Conn{
 		netConn:   netConn,
 		createdAt: time.Now(),
 	}
-	cn.rd = proto.NewReader(netConn)
-	cn.bw = bufio.NewWriter(netConn)
+
+	// Use specified buffer sizes, or fall back to 0.5MiB defaults if 0
+	if readBufSize > 0 {
+		cn.rd = proto.NewReaderSize(netConn, readBufSize)
+	} else {
+		cn.rd = proto.NewReader(netConn) // Uses 0.5MiB default
+	}
+
+	if writeBufSize > 0 {
+		cn.bw = bufio.NewWriterSize(netConn, writeBufSize)
+	} else {
+		cn.bw = bufio.NewWriterSize(netConn, proto.DefaultBufferSize)
+	}
+
 	cn.wr = proto.NewWriter(cn.bw)
 	cn.SetUsedAt(time.Now())
 	return cn

internal/pool/pool.go

@@ -71,6 +71,9 @@ type Options struct {
 	MaxActiveConns  int
 	ConnMaxIdleTime time.Duration
 	ConnMaxLifetime time.Duration
+
+	ReadBufferSize  int
+	WriteBufferSize int
 }
 
 type lastDialErrorWrap struct {
@@ -226,7 +229,7 @@ func (p *ConnPool) dialConn(ctx context.Context, pooled bool) (*Conn, error) {
 		return nil, err
 	}
 
-	cn := NewConn(netConn)
+	cn := NewConnWithBufferSize(netConn, p.cfg.ReadBufferSize, p.cfg.WriteBufferSize)
 	cn.pooled = pooled
 	return cn, nil
 }

internal/proto/reader.go

@@ -12,6 +12,9 @@ import (
 	"github.com/redis/go-redis/v9/internal/util"
 )
 
+// DefaultBufferSize is the default size for read/write buffers (0.5MiB)
+const DefaultBufferSize = 512 * 1024
+
 // redis resp protocol data type.
 const (
 	RespStatus    = '+' // +<string>\r\n
@@ -58,7 +61,13 @@ type Reader struct {
 
 func NewReader(rd io.Reader) *Reader {
 	return &Reader{
-		rd: bufio.NewReader(rd),
+		rd: bufio.NewReaderSize(rd, DefaultBufferSize),
+	}
+}
+
+func NewReaderSize(rd io.Reader, size int) *Reader {
+	return &Reader{
+		rd: bufio.NewReaderSize(rd, size),
 	}
 }
 

options.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/redis/go-redis/v9/auth"
 	"github.com/redis/go-redis/v9/internal/pool"
+	"github.com/redis/go-redis/v9/internal/proto"
 )
 
 // Limiter is the interface of a rate limiter or a circuit breaker.
@@ -130,6 +131,18 @@ type Options struct {
 	// See https://redis.uptrace.dev/guide/go-redis-debugging.html#timeouts
 	ContextTimeoutEnabled bool
 
+	// ReadBufferSize is the size of the bufio.Reader buffer for each connection.
+	// Larger buffers can improve performance for commands that return large responses.
+	//
+	// default: 0.5MiB (524288 bytes)
+	ReadBufferSize int
+
+	// WriteBufferSize is the size of the bufio.Writer buffer for each connection.
+	// Larger buffers can improve performance for large pipelines and commands with many arguments.
+	//
+	// default: 0.5MiB (524288 bytes)
+	WriteBufferSize int
+
 	// PoolFIFO type of connection pool.
 	//
 	//	- true for FIFO pool
@@ -241,6 +254,12 @@ func (opt *Options) init() {
 	if opt.PoolSize == 0 {
 		opt.PoolSize = 10 * runtime.GOMAXPROCS(0)
 	}
+	if opt.ReadBufferSize == 0 {
+		opt.ReadBufferSize = proto.DefaultBufferSize
+	}
+	if opt.WriteBufferSize == 0 {
+		opt.WriteBufferSize = proto.DefaultBufferSize
+	}
 	switch opt.ReadTimeout {
 	case -2:
 		opt.ReadTimeout = -1
@@ -592,5 +611,7 @@ func newConnPool(
 		MaxActiveConns:  opt.MaxActiveConns,
 		ConnMaxIdleTime: opt.ConnMaxIdleTime,
 		ConnMaxLifetime: opt.ConnMaxLifetime,
+		ReadBufferSize:  opt.ReadBufferSize,
+		WriteBufferSize: opt.WriteBufferSize,
 	})
 }

osscluster.go

@@ -92,6 +92,18 @@ type ClusterOptions struct {
 	ConnMaxIdleTime time.Duration
 	ConnMaxLifetime time.Duration
 
+	// ReadBufferSize is the size of the bufio.Reader buffer for each connection.
+	// Larger buffers can improve performance for commands that return large responses.
+	//
+	// default: 0.5MiB (524288 bytes)
+	ReadBufferSize int
+
+	// WriteBufferSize is the size of the bufio.Writer buffer for each connection.
+	// Larger buffers can improve performance for large pipelines and commands with many arguments.
+	//
+	// default: 0.5MiB (524288 bytes)
+	WriteBufferSize int
+
 	TLSConfig *tls.Config
 
 	// DisableIndentity - Disable set-lib on connect.
@@ -127,6 +139,12 @@ func (opt *ClusterOptions) init() {
 	if opt.PoolSize == 0 {
 		opt.PoolSize = 5 * runtime.GOMAXPROCS(0)
 	}
+	if opt.ReadBufferSize == 0 {
+		opt.ReadBufferSize = proto.DefaultBufferSize
+	}
+	if opt.WriteBufferSize == 0 {
+		opt.WriteBufferSize = proto.DefaultBufferSize
+	}
 
 	switch opt.ReadTimeout {
 	case -1:
@@ -318,6 +336,8 @@ func (opt *ClusterOptions) clientOptions() *Options {
 		MaxActiveConns:   opt.MaxActiveConns,
 		ConnMaxIdleTime:  opt.ConnMaxIdleTime,
 		ConnMaxLifetime:  opt.ConnMaxLifetime,
+		ReadBufferSize:   opt.ReadBufferSize,
+		WriteBufferSize:  opt.WriteBufferSize,
 		DisableIdentity:  opt.DisableIdentity,
 		DisableIndentity: opt.DisableIdentity,
 		IdentitySuffix:   opt.IdentitySuffix,