Merge pull request #639 from go-redis/fix/misses

Replace PoolStats.Requests with PoolStats.Misses

cluster.go

@@ -801,8 +801,8 @@ func (c *ClusterClient) PoolStats() *PoolStats {
 
 	for _, node := range state.masters {
 		s := node.Client.connPool.Stats()
-		acc.Requests += s.Requests
 		acc.Hits += s.Hits
+		acc.Misses += s.Misses
 		acc.Timeouts += s.Timeouts
 
 		acc.TotalConns += s.TotalConns
@@ -812,8 +812,8 @@ func (c *ClusterClient) PoolStats() *PoolStats {
 
 	for _, node := range state.slaves {
 		s := node.Client.connPool.Stats()
-		acc.Requests += s.Requests
 		acc.Hits += s.Hits
+		acc.Misses += s.Misses
 		acc.Timeouts += s.Timeouts
 
 		acc.TotalConns += s.TotalConns

commands_test.go

@@ -36,9 +36,9 @@ var _ = Describe("Commands", func() {
 			Expect(cmds[0].Err()).To(MatchError("ERR Client sent AUTH, but no password is set"))
 			Expect(cmds[1].Err()).To(MatchError("ERR Client sent AUTH, but no password is set"))
 
-			stats := client.Pool().Stats()
-			Expect(stats.Requests).To(Equal(uint32(2)))
+			stats := client.PoolStats()
 			Expect(stats.Hits).To(Equal(uint32(1)))
+			Expect(stats.Misses).To(Equal(uint32(1)))
 			Expect(stats.Timeouts).To(Equal(uint32(0)))
 			Expect(stats.TotalConns).To(Equal(uint32(1)))
 			Expect(stats.FreeConns).To(Equal(uint32(1)))
@@ -1391,8 +1391,8 @@ var _ = Describe("Commands", func() {
 			Expect(client.Ping().Err()).NotTo(HaveOccurred())
 
 			stats := client.PoolStats()
-			Expect(stats.Requests).To(Equal(uint32(3)))
 			Expect(stats.Hits).To(Equal(uint32(1)))
+			Expect(stats.Misses).To(Equal(uint32(2)))
 			Expect(stats.Timeouts).To(Equal(uint32(0)))
 		})
 

internal/pool/pool.go

@@ -23,8 +23,8 @@ var timers = sync.Pool{
 
 // Stats contains pool state information and accumulated stats.
 type Stats struct {
-	Requests uint32 // number of times a connection was requested by the pool
 	Hits     uint32 // number of times free connection was found in the pool
+	Misses   uint32 // number of times free connection was NOT found in the pool
 	Timeouts uint32 // number of times a wait timeout occurred
 
 	TotalConns uint32 // number of total connections in the pool
@@ -151,8 +151,6 @@ func (p *ConnPool) Get() (*Conn, bool, error) {
 		return nil, false, ErrClosed
 	}
 
-	atomic.AddUint32(&p.stats.Requests, 1)
-
 	select {
 	case p.queue <- struct{}{}:
 	default:
@@ -190,6 +188,8 @@ func (p *ConnPool) Get() (*Conn, bool, error) {
 		return cn, false, nil
 	}
 
+	atomic.AddUint32(&p.stats.Misses, 1)
+
 	newcn, err := p.NewConn()
 	if err != nil {
 		<-p.queue
@@ -266,8 +266,8 @@ func (p *ConnPool) FreeLen() int {
 
 func (p *ConnPool) Stats() *Stats {
 	return &Stats{
-		Requests: atomic.LoadUint32(&p.stats.Requests),
 		Hits:     atomic.LoadUint32(&p.stats.Hits),
+		Misses:   atomic.LoadUint32(&p.stats.Misses),
 		Timeouts: atomic.LoadUint32(&p.stats.Timeouts),
 
 		TotalConns: uint32(p.Len()),

pool_test.go

@@ -95,8 +95,8 @@ var _ = Describe("pool", func() {
 		Expect(pool.FreeLen()).To(Equal(1))
 
 		stats := pool.Stats()
-		Expect(stats.Requests).To(Equal(uint32(4)))
 		Expect(stats.Hits).To(Equal(uint32(2)))
+		Expect(stats.Misses).To(Equal(uint32(2)))
 		Expect(stats.Timeouts).To(Equal(uint32(0)))
 	})
 
@@ -112,16 +112,16 @@ var _ = Describe("pool", func() {
 		Expect(pool.FreeLen()).To(Equal(1))
 
 		stats := pool.Stats()
-		Expect(stats.Requests).To(Equal(uint32(101)))
 		Expect(stats.Hits).To(Equal(uint32(100)))
+		Expect(stats.Misses).To(Equal(uint32(1)))
 		Expect(stats.Timeouts).To(Equal(uint32(0)))
 	})
 
 	It("removes idle connections", func() {
 		stats := client.PoolStats()
 		Expect(stats).To(Equal(&redis.PoolStats{
-			Requests:   1,
 			Hits:       0,
+			Misses:     1,
 			Timeouts:   0,
 			TotalConns: 1,
 			FreeConns:  1,
@@ -132,8 +132,8 @@ var _ = Describe("pool", func() {
 
 		stats = client.PoolStats()
 		Expect(stats).To(Equal(&redis.PoolStats{
-			Requests:   1,
 			Hits:       0,
+			Misses:     1,
 			Timeouts:   0,
 			TotalConns: 0,
 			FreeConns:  0,

pubsub_test.go

@@ -68,7 +68,7 @@ var _ = Describe("PubSub", func() {
 		}
 
 		stats := client.PoolStats()
-		Expect(stats.Requests - stats.Hits).To(Equal(uint32(2)))
+		Expect(stats.Misses).To(Equal(uint32(2)))
 	})
 
 	It("should pub/sub channels", func() {
@@ -191,7 +191,7 @@ var _ = Describe("PubSub", func() {
 		}
 
 		stats := client.PoolStats()
-		Expect(stats.Requests - stats.Hits).To(Equal(uint32(2)))
+		Expect(stats.Misses).To(Equal(uint32(2)))
 	})
 
 	It("should ping/pong", func() {
@@ -290,8 +290,8 @@ var _ = Describe("PubSub", func() {
 		Eventually(done).Should(Receive())
 
 		stats := client.PoolStats()
-		Expect(stats.Requests).To(Equal(uint32(2)))
 		Expect(stats.Hits).To(Equal(uint32(1)))
+		Expect(stats.Misses).To(Equal(uint32(1)))
 	})
 
 	It("returns an error when subscribe fails", func() {

ring.go

@@ -148,6 +148,7 @@ type Ring struct {
 	mu         sync.RWMutex
 	hash       *consistenthash.Map
 	shards     map[string]*ringShard
+	shardsList []*ringShard
 
 	cmdsInfoOnce internal.Once
 	cmdsInfo     map[string]*CommandInfo
@@ -169,12 +170,21 @@ func NewRing(opt *RingOptions) *Ring {
 	for name, addr := range opt.Addrs {
 		clopt := opt.clientOptions()
 		clopt.Addr = addr
-		ring.addClient(name, NewClient(clopt))
+		ring.addShard(name, NewClient(clopt))
 	}
 	go ring.heartbeat()
 	return ring
 }
 
+func (c *Ring) addShard(name string, cl *Client) {
+	shard := &ringShard{Client: cl}
+	c.mu.Lock()
+	c.hash.Add(name)
+	c.shards[name] = shard
+	c.shardsList = append(c.shardsList, shard)
+	c.mu.Unlock()
+}
+
 // Options returns read-only Options that were used to create the client.
 func (c *Ring) Options() *RingOptions {
 	return c.opt
@@ -186,11 +196,15 @@ func (c *Ring) retryBackoff(attempt int) time.Duration {
 
 // PoolStats returns accumulated connection pool stats.
 func (c *Ring) PoolStats() *PoolStats {
+	c.mu.RLock()
+	shards := c.shardsList
+	c.mu.RUnlock()
+
 	var acc PoolStats
-	for _, shard := range c.shards {
+	for _, shard := range shards {
 		s := shard.Client.connPool.Stats()
-		acc.Requests += s.Requests
 		acc.Hits += s.Hits
+		acc.Misses += s.Misses
 		acc.Timeouts += s.Timeouts
 		acc.TotalConns += s.TotalConns
 		acc.FreeConns += s.FreeConns
@@ -229,9 +243,13 @@ func (c *Ring) PSubscribe(channels ...string) *PubSub {
 // ForEachShard concurrently calls the fn on each live shard in the ring.
 // It returns the first error if any.
 func (c *Ring) ForEachShard(fn func(client *Client) error) error {
+	c.mu.RLock()
+	shards := c.shardsList
+	c.mu.RUnlock()
+
 	var wg sync.WaitGroup
 	errCh := make(chan error, 1)
-	for _, shard := range c.shards {
+	for _, shard := range shards {
 		if shard.IsDown() {
 			continue
 		}
@@ -261,10 +279,11 @@ func (c *Ring) ForEachShard(fn func(client *Client) error) error {
 func (c *Ring) cmdInfo(name string) *CommandInfo {
 	err := c.cmdsInfoOnce.Do(func() error {
 		c.mu.RLock()
-		defer c.mu.RUnlock()
+		shards := c.shardsList
+		c.mu.RUnlock()
 
 		var firstErr error
-		for _, shard := range c.shards {
+		for _, shard := range shards {
 			cmdsInfo, err := shard.Client.Command().Result()
 			if err == nil {
 				c.cmdsInfo = cmdsInfo
@@ -286,13 +305,6 @@ func (c *Ring) cmdInfo(name string) *CommandInfo {
 	return info
 }
 
-func (c *Ring) addClient(name string, cl *Client) {
-	c.mu.Lock()
-	c.hash.Add(name)
-	c.shards[name] = &ringShard{Client: cl}
-	c.mu.Unlock()
-}
-
 func (c *Ring) shardByKey(key string) (*ringShard, error) {
 	key = hashtag.Key(key)
 
@@ -372,7 +384,10 @@ func (c *Ring) heartbeat() {
 			break
 		}
 
-		for _, shard := range c.shards {
+		shards := c.shardsList
+		c.mu.RUnlock()
+
+		for _, shard := range shards {
 			err := shard.Client.Ping().Err()
 			if shard.Vote(err == nil || err == pool.ErrPoolTimeout) {
 				internal.Logf("ring shard state changed: %s", shard)
@@ -380,8 +395,6 @@ func (c *Ring) heartbeat() {
 			}
 		}
 
-		c.mu.RUnlock()
-
 		if rebalance {
 			c.rebalance()
 		}
@@ -409,6 +422,7 @@ func (c *Ring) Close() error {
 	}
 	c.hash = nil
 	c.shards = nil
+	c.shardsList = nil
 
 	return firstErr
 }