cluster: don't reload slots if address already changed.

Author: vmihailenco

cluster.go

@@ -97,6 +97,14 @@ func (c *ClusterClient) slotAddrs(slot int) []string {
 	return addrs
 }
 
+func (c *ClusterClient) slotMasterAddr(slot int) string {
+	addrs := c.slotAddrs(slot)
+	if len(addrs) > 0 {
+		return addrs[0]
+	}
+	return ""
+}
+
 // randomClient returns a Client for the first pingable node.
 func (c *ClusterClient) randomClient() (client *Client, err error) {
 	for i := 0; i < 10; i++ {
@@ -118,11 +126,7 @@ func (c *ClusterClient) process(cmd Cmder) {
 
 	slot := hashSlot(cmd.clusterKey())
 
-	var addr string
-	if addrs := c.slotAddrs(slot); len(addrs) > 0 {
-		addr = addrs[0] // First address is master.
-	}
-
+	addr := c.slotMasterAddr(slot)
 	client, err := c.getClient(addr)
 	if err != nil {
 		cmd.setErr(err)
@@ -160,7 +164,7 @@ func (c *ClusterClient) process(cmd Cmder) {
 		var addr string
 		moved, ask, addr = isMovedError(err)
 		if moved || ask {
-			if moved {
+			if moved && c.slotMasterAddr(slot) != addr {
 				c.lazyReloadSlots()
 			}
 			client, err = c.getClient(addr)

cluster_pipeline.go

@@ -53,13 +53,7 @@ func (c *ClusterPipeline) Exec() (cmds []Cmder, retErr error) {
 	cmdsMap := make(map[string][]Cmder)
 	for _, cmd := range cmds {
 		slot := hashSlot(cmd.clusterKey())
-		addrs := c.cluster.slotAddrs(slot)
-
-		var addr string
-		if len(addrs) > 0 {
-			addr = addrs[0] // First address is master.
-		}
-
+		addr := c.cluster.slotMasterAddr(slot)
 		cmdsMap[addr] = append(cmdsMap[addr], cmd)
 	}