go: Remove Select command from cluster clients

- Remove Select method from ClusterClient and related interfaces
- Delete comprehensive database_id integration tests
- Remove Select command from batch operations
- Remove Select examples and tests
- Add example for cluster client with database_id configuration

The Select command is being removed in favor of using the database_id
configuration parameter, which provides persistent database selection
across reconnections.

Signed-off-by: affonsov <67347924+affonsov@users.noreply.github.com>

Author: affonsov

go/create_client_test.go

@@ -54,3 +54,27 @@ func ExampleNewClusterClient() {
 	// Output:
 	// Client created and connected: *glide.ClusterClient
 }
+
+func ExampleNewClusterClient_withDatabaseId() {
+	// This WithDatabaseId for cluster requires Valkey 9.0+
+	clientConf := config.NewClusterClientConfiguration().
+		WithAddress(&getClusterAddresses()[0]).
+		WithRequestTimeout(5 * time.Second).
+		WithUseTLS(false).
+		WithDatabaseId(1).
+		WithSubscriptionConfig(
+			config.NewClusterSubscriptionConfig().
+				WithSubscription(config.PatternClusterChannelMode, "news.*").
+				WithCallback(func(message *models.PubSubMessage, ctx any) {
+					fmt.Printf("Received message on '%s': %s", message.Channel, message.Message)
+				}, nil),
+		)
+	client, err := NewClusterClient(clientConf)
+	if err != nil {
+		fmt.Println("Failed to create a client and connect: ", err)
+	}
+	fmt.Printf("Client created and connected: %T", client)
+
+	// Output:
+	// Client created and connected: *glide.ClusterClient
+}

go/glide_cluster_client.go

@@ -335,47 +335,6 @@ func (client *ClusterClient) CustomCommandWithRoute(ctx context.Context,
 	return models.CreateClusterValue[any](data), nil
 }
 
-// Select changes the currently selected database on cluster nodes.
-// The command will be routed to all primary nodes by default.
-//
-// WARNING: This command is NOT RECOMMENDED for production use.
-// Upon reconnection, nodes will revert to the database_id specified
-// in the client configuration (default: 0), NOT the database selected
-// via this command.
-//
-// RECOMMENDED APPROACH: Use the database_id parameter in client
-// configuration instead:
-//
-//	config := &config.ClusterClientConfiguration{
-//		Addresses: []config.NodeAddress{{Host: "localhost", Port: 6379}},
-//		DatabaseId: &databaseId, // Recommended: persists across reconnections
-//	}
-//	client, err := NewClusterClient(config)
-//
-// CLUSTER BEHAVIOR: This command routes to all nodes by default
-// to maintain consistency across the cluster.
-//
-// See [valkey.io] for details.
-//
-// Parameters:
-//
-//	ctx - The context for controlling the command execution.
-//	index - The index of the database to select.
-//
-// Return value:
-//
-//	A simple `"OK"` response.
-//
-// [valkey.io]: https://valkey.io/commands/select/
-func (client *ClusterClient) Select(ctx context.Context, index int64) (string, error) {
-	result, err := client.executeCommand(ctx, C.Select, []string{utils.IntToString(index)})
-	if err != nil {
-		return models.DefaultStringResponse, err
-	}
-
-	return handleOkResponse(result)
-}
-
 // Pings the server.
 // The command will be routed to all primary nodes.
 //

go/integTest/cluster_commands_test.go

@@ -2677,33 +2677,3 @@ func (suite *GlideTestSuite) TestBatchWithSingleNodeRoute() {
 		assert.Contains(suite.T(), res[0], "# Replication", "isAtomic = %v", isAtomic)
 	}
 }
-
-func (suite *GlideTestSuite) TestClusterSelect_WithValidIndex() {
-	suite.SkipIfServerVersionLowerThan("9.0.0", suite.T())
-
-	client := suite.defaultClusterClient()
-	index := int64(1)
-	suite.verifyOK(client.Select(context.Background(), index))
-
-	key := uuid.New().String()
-	value := uuid.New().String()
-	suite.verifyOK(client.Set(context.Background(), key, value))
-
-	res, err := client.Get(context.Background(), key)
-	suite.NoError(err)
-	assert.Equal(suite.T(), value, res.Value())
-}
-
-func (suite *GlideTestSuite) TestClusterSelect_InvalidIndex_OutOfBounds() {
-	suite.SkipIfServerVersionLowerThan("9.0.0", suite.T())
-
-	client := suite.defaultClusterClient()
-
-	result, err := client.Select(context.Background(), -1)
-	assert.NotNil(suite.T(), err)
-	assert.Equal(suite.T(), "", result)
-
-	result, err = client.Select(context.Background(), 1000)
-	assert.NotNil(suite.T(), err)
-	assert.Equal(suite.T(), "", result)
-}