perf: pooled connection`s instantiation

- pooled connection: reduce the pressure on the GC to process heap memory objects with high concurrent "connection"

database/replication.go

@@ -383,6 +383,7 @@ func (mdb *MultiDB) receiveAOF(ctx context.Context, configVersion int32) error {
 				n, mdb.replication.replOffset, strconv.Quote(string(cmdLine.ToBytes()))))
 			mdb.replication.mutex.Unlock()
 		case <-ctx.Done():
+			conn.GetConnPool().Put(conn)
 			return nil
 		}
 	}
@@ -420,7 +421,7 @@ func (repl *slaveStatus) sendAck2Master() error {
 		strconv.FormatInt(repl.replOffset, 10))
 	psyncReq := protocol.MakeMultiBulkReply(psyncCmdLine)
 	_, err := repl.masterConn.Write(psyncReq.ToBytes())
-	//logger.Info("send ack to master")
+	// logger.Info("send ack to master")
 	return err
 }
 

redis/connection/conn.go

@@ -2,6 +2,7 @@ package connection
 
 import (
 	"bytes"
+	"github.com/hdt3213/godis/lib/logger"
 	"github.com/hdt3213/godis/lib/sync/wait"
 	"net"
 	"sync"
@@ -42,6 +43,17 @@ type Connection struct {
 	role       int32
 }
 
+var connPool = sync.Pool{
+	New: func() interface{} {
+		return &Connection{}
+	},
+}
+
+// GetConnPool returns the connection pool pointer for putting and getting connection
+func (c *Connection) GetConnPool() *sync.Pool {
+	return &connPool
+}
+
 // RemoteAddr returns the remote network address
 func (c *Connection) RemoteAddr() net.Addr {
 	return c.conn.RemoteAddr()
@@ -56,9 +68,15 @@ func (c *Connection) Close() error {
 
 // NewConn creates Connection instance
 func NewConn(conn net.Conn) *Connection {
-	return &Connection{
+	c, ok := connPool.Get().(*Connection)
-		conn: conn,
+	if !ok {
+		logger.Error("connection pool make wrong type")
+		return &Connection{
+			conn: conn,
+		}
 	}
+	c.conn = conn
+	return c
 }
 
 // Write sends response to client over tcp connection

redis/server/server.go

@@ -50,6 +50,8 @@ func (h *Handler) closeClient(client *connection.Connection) {
 	_ = client.Close()
 	h.db.AfterClientClose(client)
 	h.activeConn.Delete(client)
+
+	client.GetConnPool().Put(client)
 }
 
 // Handle receives and executes redis commands