diff --git a/core/decoder.go b/core/decoder.go
index f0c83c5..c58c0ba 100644
--- a/core/decoder.go
+++ b/core/decoder.go
@@ -9,6 +9,8 @@ import (
 	"fmt"
 	"io"
 	"strconv"
+	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/hdt3213/rdb/memprofiler"
@@ -18,19 +20,31 @@ import (
 // Decoder is an instance of rdb parsing process
 type Decoder struct {
 	input     *bufio.Reader
-	readCount int
+	readCount int64
 	buffer    []byte
+	// to reduce disk IOPS
+	cache []byte
+	// Current Read Offset
+	cachePos atomic.Uint32
+	// Effective length of `cache`
+	cacheLen atomic.Uint32
+	// lock for real IO operations
+	refillMu sync.Mutex
 
 	withSpecialOpCode bool
 	withSpecialTypes  map[string]ModuleTypeHandleFunc
 }
 
+// cacheSize 1MB
+const cacheSize = 1024 * 1024
+
 // NewDecoder creates a new RDB decoder
 func NewDecoder(reader io.Reader) *Decoder {
 	parser := new(Decoder)
 	parser.input = bufio.NewReader(reader)
 	parser.buffer = make([]byte, 8)
 	parser.withSpecialTypes = make(map[string]ModuleTypeHandleFunc)
+	parser.cache = make([]byte, cacheSize)
 	return parser
 }
 
@@ -54,7 +68,8 @@ const (
 )
 
 const (
-	opCodeFunction     = 245
+	opCodeSlotInfo     = 244 /* Individual slot info, such as slot id and size (cluster mode only). */
+	opCodeFunction     = 245 /* function library data */
 	opCodeModuleAux    = 247 /* Module auxiliary data. */
 	opCodeIdle         = 248 /* LRU idle time. */
 	opCodeFreq         = 249 /* LFU frequency. */
@@ -466,6 +481,23 @@ func (dec *Decoder) parse(cb func(object model.RedisObject) bool) error {
 				}
 			}
 			continue
+		} else if b == opCodeSlotInfo {
+			// slot id
+			_, _, err = dec.readLength()
+			if err != nil {
+				return err
+			}
+			// slot size
+			_, _, err = dec.readLength()
+			if err != nil {
+				return err
+			}
+			// expires slot size
+			_, _, err = dec.readLength()
+			if err != nil {
+				return err
+			}
+			continue
 		}
 		key, err := dec.readString()
 		if err != nil {
@@ -511,6 +543,6 @@ func (dec *Decoder) Parse(cb func(object model.RedisObject) bool) (err error) {
 	return dec.parse(cb)
 }
 
-func (dec *Decoder) GetReadCount() int {
+func (dec *Decoder) GetReadCount() int64 {
 	return dec.readCount
 }
diff --git a/core/utils.go b/core/utils.go
index f16af08..c0f8206 100644
--- a/core/utils.go
+++ b/core/utils.go
@@ -5,6 +5,7 @@ import (
 	"errors"
 	"io"
 	"math/rand"
+	"sync/atomic"
 	"unsafe"
 )
 
@@ -42,7 +43,8 @@ func readZipListLength(buf []byte, cursor *int) int {
 	return size
 }
 
-func (dec *Decoder) readByte() (byte, error) {
+// original code
+/*func (dec *Decoder) readByte() (byte, error) {
 	b, err := dec.input.ReadByte()
 	if err != nil {
 		return 0, err
@@ -58,6 +60,92 @@ func (dec *Decoder) readFull(buf []byte) error {
 	}
 	dec.readCount += n
 	return nil
+}*/
+
+// readByte get 1 Byte from Decoder.cache
+func (dec *Decoder) readByte() (byte, error) {
+	for {
+		pos := dec.cachePos.Load()
+		length := dec.cacheLen.Load()
+
+		if pos >= length {
+			dec.refillMu.Lock()
+			if dec.cachePos.Load() < dec.cacheLen.Load() {
+				dec.refillMu.Unlock()
+				continue
+			}
+			err := dec.refillCache()
+			dec.refillMu.Unlock()
+			if err != nil {
+				return 0, err
+			}
+			continue
+		}
+
+		if dec.cachePos.CompareAndSwap(pos, pos+1) {
+			atomic.AddInt64(&dec.readCount, 1)
+			return dec.cache[pos], nil
+		}
+	}
+}
+
+// readFull get len(buf) Bytes from Decoder.cache
+func (dec *Decoder) readFull(buf []byte) error {
+	need := len(buf)
+	copied := 0
+
+	for copied < need {
+		pos := dec.cachePos.Load()
+		length := dec.cacheLen.Load()
+
+		if pos >= length {
+			dec.refillMu.Lock()
+			if dec.cachePos.Load() < dec.cacheLen.Load() {
+				dec.refillMu.Unlock()
+				continue
+			}
+			err := dec.refillCache()
+			dec.refillMu.Unlock()
+			if err != nil {
+				if copied > 0 && err == io.EOF {
+					return io.ErrUnexpectedEOF
+				}
+				return err
+			}
+			continue
+		}
+
+		available := int(length - pos)
+		toCopy := need - copied
+		if toCopy > available {
+			toCopy = available
+		}
+
+		if dec.cachePos.CompareAndSwap(pos, pos+uint32(toCopy)) {
+			copy(buf[copied:copied+toCopy], dec.cache[pos:pos+uint32(toCopy)])
+			copied += toCopy
+			atomic.AddInt64(&dec.readCount, int64(toCopy))
+		}
+	}
+	return nil
+}
+
+// refillCache read 1MiB from disk
+func (dec *Decoder) refillCache() error {
+	n, err := dec.input.Read(dec.cache)
+
+	// eof
+	if n == 0 && err == nil {
+		return io.EOF
+	}
+
+	if n > 0 {
+		dec.cachePos.Store(0)
+		dec.cacheLen.Store(uint32(n))
+		return nil
+	}
+
+	return err
 }
 
 var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")