diff --git a/error.go b/error.go
index 6f47f7cf..8c811966 100644
--- a/error.go
+++ b/error.go
@@ -15,6 +15,13 @@ import (
 // ErrClosed performs any operation on the closed client will return this error.
 var ErrClosed = pool.ErrClosed
 
+// ErrPoolExhausted is returned from a pool connection method
+// when the maximum number of database connections in the pool has been reached.
+var ErrPoolExhausted = pool.ErrPoolExhausted
+
+// ErrPoolTimeout timed out waiting to get a connection from the connection pool.
+var ErrPoolTimeout = pool.ErrPoolTimeout
+
 // HasErrorPrefix checks if the err is a Redis error and the message contains a prefix.
 func HasErrorPrefix(err error, prefix string) bool {
 	var rErr Error
diff --git a/export_test.go b/export_test.go
index 10d8f23c..c1b77683 100644
--- a/export_test.go
+++ b/export_test.go
@@ -11,8 +11,6 @@ import (
 	"github.com/redis/go-redis/v9/internal/pool"
 )
 
-var ErrPoolTimeout = pool.ErrPoolTimeout
-
 func (c *baseClient) Pool() pool.Pooler {
 	return c.connPool
 }
diff --git a/internal/pool/pool_test.go b/internal/pool/pool_test.go
index d198ba54..0f366cc7 100644
--- a/internal/pool/pool_test.go
+++ b/internal/pool/pool_test.go
@@ -387,4 +387,33 @@ var _ = Describe("race", func() {
 		Expect(stats.WaitCount).To(Equal(uint32(1)))
 		Expect(stats.WaitDurationNs).To(BeNumerically("~", time.Second.Nanoseconds(), 100*time.Millisecond.Nanoseconds()))
 	})
+
+	It("timeout", func() {
+		testPoolTimeout := 1 * time.Second
+		opt := &pool.Options{
+			Dialer: func(ctx context.Context) (net.Conn, error) {
+				// Artificial delay to force pool timeout
+				time.Sleep(3 * testPoolTimeout)
+
+				return &net.TCPConn{}, nil
+			},
+			PoolSize:    1,
+			PoolTimeout: testPoolTimeout,
+		}
+		p := pool.NewConnPool(opt)
+
+		stats := p.Stats()
+		Expect(stats.Timeouts).To(Equal(uint32(0)))
+
+		conn, err := p.Get(ctx)
+		Expect(err).NotTo(HaveOccurred())
+		_, err = p.Get(ctx)
+		Expect(err).To(MatchError(pool.ErrPoolTimeout))
+		p.Put(ctx, conn)
+		conn, err = p.Get(ctx)
+		Expect(err).NotTo(HaveOccurred())
+
+		stats = p.Stats()
+		Expect(stats.Timeouts).To(Equal(uint32(1)))
+	})
 })
diff --git a/internal/util.go b/internal/util.go
index cc1bff24..f77775ff 100644
--- a/internal/util.go
+++ b/internal/util.go
@@ -49,22 +49,7 @@ func isLower(s string) bool {
 }
 
 func ReplaceSpaces(s string) string {
-	// Pre-allocate a builder with the same length as s to minimize allocations.
-	// This is a basic optimization; adjust the initial size based on your use case.
-	var builder strings.Builder
-	builder.Grow(len(s))
-
-	for _, char := range s {
-		if char == ' ' {
-			// Replace space with a hyphen.
-			builder.WriteRune('-')
-		} else {
-			// Copy the character as-is.
-			builder.WriteRune(char)
-		}
-	}
-
-	return builder.String()
+	return strings.ReplaceAll(s, " ", "-")
 }
 
 func GetAddr(addr string) string {
diff --git a/internal/util_test.go b/internal/util_test.go
index 57f7f9fa..0bc46646 100644
--- a/internal/util_test.go
+++ b/internal/util_test.go
@@ -1,6 +1,7 @@
 package internal
 
 import (
+	"runtime"
 	"strings"
 	"testing"
 
@@ -72,3 +73,36 @@ func TestGetAddr(t *testing.T) {
 		Expect(GetAddr("127")).To(Equal(""))
 	})
 }
+
+func BenchmarkReplaceSpaces(b *testing.B) {
+	version := runtime.Version()
+	for i := 0; i < b.N; i++ {
+		_ = ReplaceSpaces(version)
+	}
+}
+
+func ReplaceSpacesUseBuilder(s string) string {
+	// Pre-allocate a builder with the same length as s to minimize allocations.
+	// This is a basic optimization; adjust the initial size based on your use case.
+	var builder strings.Builder
+	builder.Grow(len(s))
+
+	for _, char := range s {
+		if char == ' ' {
+			// Replace space with a hyphen.
+			builder.WriteRune('-')
+		} else {
+			// Copy the character as-is.
+			builder.WriteRune(char)
+		}
+	}
+
+	return builder.String()
+}
+
+func BenchmarkReplaceSpacesUseBuilder(b *testing.B) {
+	version := runtime.Version()
+	for i := 0; i < b.N; i++ {
+		_ = ReplaceSpacesUseBuilder(version)
+	}
+}
diff --git a/internal_test.go b/internal_test.go
index a61b5c02..8f1f1f31 100644
--- a/internal_test.go
+++ b/internal_test.go
@@ -364,14 +364,14 @@ var _ = Describe("ClusterClient", func() {
 		It("select slot from args for GETKEYSINSLOT command", func() {
 			cmd := NewStringSliceCmd(ctx, "cluster", "getkeysinslot", 100, 200)
 
-			slot := client.cmdSlot(context.Background(), cmd)
+			slot := client.cmdSlot(cmd)
 			Expect(slot).To(Equal(100))
 		})
 
 		It("select slot from args for COUNTKEYSINSLOT command", func() {
 			cmd := NewStringSliceCmd(ctx, "cluster", "countkeysinslot", 100)
 
-			slot := client.cmdSlot(context.Background(), cmd)
+			slot := client.cmdSlot(cmd)
 			Expect(slot).To(Equal(100))
 		})
 	})
diff --git a/osscluster.go b/osscluster.go
index 0ccb087d..5dbcc936 100644
--- a/osscluster.go
+++ b/osscluster.go
@@ -984,7 +984,7 @@ func (c *ClusterClient) Process(ctx context.Context, cmd Cmder) error {
 }
 
 func (c *ClusterClient) process(ctx context.Context, cmd Cmder) error {
-	slot := c.cmdSlot(ctx, cmd)
+	slot := c.cmdSlot(cmd)
 	var node *clusterNode
 	var moved bool
 	var ask bool
@@ -1332,7 +1332,7 @@ func (c *ClusterClient) mapCmdsByNode(ctx context.Context, cmdsMap *cmdsMap, cmd
 
 	if c.opt.ReadOnly && c.cmdsAreReadOnly(ctx, cmds) {
 		for _, cmd := range cmds {
-			slot := c.cmdSlot(ctx, cmd)
+			slot := c.cmdSlot(cmd)
 			node, err := c.slotReadOnlyNode(state, slot)
 			if err != nil {
 				return err
@@ -1343,7 +1343,7 @@ func (c *ClusterClient) mapCmdsByNode(ctx context.Context, cmdsMap *cmdsMap, cmd
 	}
 
 	for _, cmd := range cmds {
-		slot := c.cmdSlot(ctx, cmd)
+		slot := c.cmdSlot(cmd)
 		node, err := state.slotMasterNode(slot)
 		if err != nil {
 			return err
@@ -1543,7 +1543,7 @@ func (c *ClusterClient) processTxPipeline(ctx context.Context, cmds []Cmder) err
 func (c *ClusterClient) mapCmdsBySlot(ctx context.Context, cmds []Cmder) map[int][]Cmder {
 	cmdsMap := make(map[int][]Cmder)
 	for _, cmd := range cmds {
-		slot := c.cmdSlot(ctx, cmd)
+		slot := c.cmdSlot(cmd)
 		cmdsMap[slot] = append(cmdsMap[slot], cmd)
 	}
 	return cmdsMap
@@ -1572,7 +1572,7 @@ func (c *ClusterClient) processTxPipelineNode(
 }
 
 func (c *ClusterClient) processTxPipelineNodeConn(
-	ctx context.Context, node *clusterNode, cn *pool.Conn, cmds []Cmder, failedCmds *cmdsMap,
+	ctx context.Context, _ *clusterNode, cn *pool.Conn, cmds []Cmder, failedCmds *cmdsMap,
 ) error {
 	if err := cn.WithWriter(c.context(ctx), c.opt.WriteTimeout, func(wr *proto.Writer) error {
 		return writeCmds(wr, cmds)
@@ -1861,7 +1861,7 @@ func (c *ClusterClient) cmdInfo(ctx context.Context, name string) *CommandInfo {
 	return info
 }
 
-func (c *ClusterClient) cmdSlot(ctx context.Context, cmd Cmder) int {
+func (c *ClusterClient) cmdSlot(cmd Cmder) int {
 	args := cmd.Args()
 	if args[0] == "cluster" && (args[1] == "getkeysinslot" || args[1] == "countkeysinslot") {
 		return args[2].(int)
diff --git a/ring.go b/ring.go
index 555ea2a1..ab3d0626 100644
--- a/ring.go
+++ b/ring.go
@@ -349,17 +349,16 @@ func (c *ringSharding) newRingShards(
 	return
 }
 
+// Warning: External exposure of `c.shards.list` may cause data races.
+// So keep internal or implement deep copy if exposed.
 func (c *ringSharding) List() []*ringShard {
-	var list []*ringShard
-
 	c.mu.RLock()
-	if !c.closed {
-		list = make([]*ringShard, len(c.shards.list))
-		copy(list, c.shards.list)
-	}
-	c.mu.RUnlock()
+	defer c.mu.RUnlock()
 
-	return list
+	if c.closed {
+		return nil
+	}
+	return c.shards.list
 }
 
 func (c *ringSharding) Hash(key string) string {
@@ -423,6 +422,7 @@ func (c *ringSharding) Heartbeat(ctx context.Context, frequency time.Duration) {
 		case <-ticker.C:
 			var rebalance bool
 
+			// note: `c.List()` return a shadow copy of `[]*ringShard`.
 			for _, shard := range c.List() {
 				err := shard.Client.Ping(ctx).Err()
 				isUp := err == nil || err == pool.ErrPoolTimeout
@@ -582,6 +582,7 @@ func (c *Ring) retryBackoff(attempt int) time.Duration {
 
 // PoolStats returns accumulated connection pool stats.
 func (c *Ring) PoolStats() *PoolStats {
+	// note: `c.List()` return a shadow copy of `[]*ringShard`.
 	shards := c.sharding.List()
 	var acc PoolStats
 	for _, shard := range shards {
@@ -651,6 +652,7 @@ func (c *Ring) ForEachShard(
 	ctx context.Context,
 	fn func(ctx context.Context, client *Client) error,
 ) error {
+	// note: `c.List()` return a shadow copy of `[]*ringShard`.
 	shards := c.sharding.List()
 	var wg sync.WaitGroup
 	errCh := make(chan error, 1)
@@ -682,6 +684,7 @@ func (c *Ring) ForEachShard(
 }
 
 func (c *Ring) cmdsInfo(ctx context.Context) (map[string]*CommandInfo, error) {
+	// note: `c.List()` return a shadow copy of `[]*ringShard`.
 	shards := c.sharding.List()
 	var firstErr error
 	for _, shard := range shards {
@@ -810,7 +813,7 @@ func (c *Ring) Watch(ctx context.Context, fn func(*Tx) error, keys ...string) er
 
 	for _, key := range keys {
 		if key != "" {
-			shard, err := c.sharding.GetByKey(hashtag.Key(key))
+			shard, err := c.sharding.GetByKey(key)
 			if err != nil {
 				return err
 			}