struct CassCluster
A cluster object describes the configuration of the Cassandra cluster and is used to construct a session instance. Unlike other DataStax drivers the cluster object does not maintain the control connection.
Functions
CassCluster * cass_cluster_new_dse
( )Creates a new cluster with DSE specific settings.
CassError cass_cluster_set_dse_gssapi_authenticator
(CassCluster * cluster, const char * service, const char * principal )
Enables GSSAPI authentication for DSE clusters secured with the DseAuthenticator.
CassError cass_cluster_set_dse_gssapi_authenticator_n
(CassCluster * cluster, const char * service, size_t service_length, const char * principal, size_t principal_length )
Same as CassCluster::cass_cluster_set_dse_gssapi_authenticator, but with lengths for string parameters.
CassError cass_cluster_set_dse_gssapi_authenticator_proxy
(CassCluster * cluster, const char * service, const char * principal, const char * authorization_id )
Enables GSSAPI authentication with proxy authorization for DSE clusters secured with the DseAuthenticator.
CassError cass_cluster_set_dse_gssapi_authenticator_proxy_n
(CassCluster * cluster, const char * service, size_t service_length, const char * principal, size_t principal_length, const char * authorization_id, size_t authorization_id_length )
Same as CassCluster::cass_cluster_set_dse_gssapi_authenticator_proxy, but with lengths for string parameters.
CassError cass_cluster_set_dse_plaintext_authenticator
(CassCluster * cluster, const char * username, const char * password )
Enables plaintext authentication for DSE clusters secured with the DseAuthenticator.
CassError cass_cluster_set_dse_plaintext_authenticator_n
(CassCluster * cluster, const char * username, size_t username_length, const char * password, size_t password_length )
Same as CassCluster::cass_cluster_set_dse_plaintext_authenticator, but with lengths for string parameters.
CassError cass_cluster_set_dse_plaintext_authenticator_proxy
(CassCluster * cluster, const char * username, const char * password, const char * authorization_id )
Enables plaintext authentication with proxy authorization for DSE clusters secured with the DseAuthenticator.
CassError cass_cluster_set_dse_plaintext_authenticator_proxy_n
(CassCluster * cluster, const char * username, size_t username_length, const char * password, size_t password_length, const char * authorization_id, size_t authorization_id_length )
Same as CassCluster::cass_cluster_set_dse_plaintext_authenticator_proxy, but with lengths for string parameters.
Set the application name.
This is optional; however it provides the server with the application name that can aid in debugging issues with larger clusters where there are a lot of client (or application) connections.
void cass_cluster_set_application_name_n
(CassCluster * cluster, const char * application_name, size_t application_name_length, application_length )
Same as CassCluster::cass_cluster_set_application_name, but with lengths for string parameters.
void cass_cluster_set_application_version
(CassCluster * cluster, const char * application_version, application_name_version )
Set the application version.
This is optional; however it provides the server with the application version that can aid in debugging issues with large clusters where there are a lot of client (or application) connections that may have different versions in use.
void cass_cluster_set_application_version_n
(CassCluster * cluster, const char * application_version, size_t application_version_length )
Same as CassCluster::cass_cluster_set_application_version, but with lengths for string parameters.
Set the client id.
This is optional; however it provides the server with the client ID that can aid in debugging issues with large clusters where there are a lot of client connections.
Default: UUID v4 generated (
Sets the amount of time between monitor reporting event messages.
Default: 300 seconds.
CassCluster * cass_cluster_new
( )Creates a new cluster.
Frees a cluster instance.
Sets/Appends contact points. This MUST be set. The first call sets the contact points and any subsequent calls appends additional contact points. Passing an empty string will clear the contact points. White space is striped from the contact points.
Examples: “127.0.0.1” “127.0.0.1,127.0.0.2”, “server1.domain.com”
CassError cass_cluster_set_contact_points_n
(CassCluster * cluster, const char * contact_points, size_t contact_points_length )
Same as CassCluster::cass_cluster_set_contact_points, but with lengths for string parameters.
Sets the port.
Default: 9042
Sets the local address to bind when connecting to the cluster, if desired.
CassError cass_cluster_set_local_address_n
(CassCluster * cluster, const char * name, size_t name_length )
Same as CassCluster::cass_cluster_set_local_address, but with lengths for string parameters.
Sets the SSL context and enables SSL.
CassError cass_cluster_set_authenticator_callbacks
(CassCluster * cluster, const CassAuthenticatorCallbacks * exchange_callbacks, CassAuthenticatorDataCleanupCallback cleanup_callback, void * data )
Sets custom authenticator
Sets the protocol version. The driver will automatically downgrade to the lowest supported protocol version.
Default: CASS_PROTOCOL_VERSION_V4 or CASS_PROTOCOL_VERSION_DSEV1 when using the DSE driver with DataStax Enterprise.
Use the newest beta protocol version. This currently enables the use of protocol version v5 (CASS_PROTOCOL_VERSION_V5) or DSEv2 (CASS_PROTOCOL_VERSION_DSEV2) when using the DSE driver with DataStax Enterprise.
Default: cass_false
Sets default consistency level of statement.
Default: CASS_CONSISTENCY_LOCAL_ONE
CassError cass_cluster_set_serial_consistency
(CassCluster * cluster, CassConsistency consistency )
Sets default serial consistency level of statement.
Default: CASS_CONSISTENCY_ANY
Sets the number of IO threads. This is the number of threads that will handle query requests.
Default: 1
Sets the size of the fixed size queue that stores pending requests.
Default: 8192
Sets the size of the fixed size queue that stores events.
Default: 8192
Deprecated:
This is no longer useful and does nothing. Expect this to be removed in a future release.
CassError cass_cluster_set_core_connections_per_host
(CassCluster * cluster, unsigned num_connections )
Sets the number of connections made to each server in each IO thread.
Default: 1
CassError cass_cluster_set_max_connections_per_host
(CassCluster * cluster, unsigned num_connections )
Sets the maximum number of connections made to each server in each IO thread.
Default: 2
Deprecated:
This is no longer useful and does nothing. Expect this to be removed in a future release.
Sets the amount of time to wait before attempting to reconnect.
Default: 2000 milliseconds
Sets the amount of time, in microseconds, to wait for new requests to coalesce into a single system call. This should be set to a value around the latency SLA of your application’s requests while also considering the request’s roundtrip time. Larger values should be used for throughput bound workloads and lower values should be used for latency bound workloads.
Default: 200 us
Sets the ratio of time spent processing new requests versus handling the I/O and processing of outstanding requests. The range of this setting is 1 to 100, where larger values allocate more time to processing new requests and smaller values allocate more time to processing outstanding requests.
Default: 50
CassError cass_cluster_set_max_concurrent_creation
(CassCluster * cluster, unsigned num_connections )
Sets the maximum number of connections that will be created concurrently. Connections are created when the current connections are unable to keep up with request throughput.
Default: 1
Deprecated:
This is no longer useful and does nothing. Expect this to be removed in a future release.
CassError cass_cluster_set_max_concurrent_requests_threshold
(CassCluster * cluster, unsigned num_requests )
Sets the threshold for the maximum number of concurrent requests in-flight on a connection before creating a new connection. The number of new connections created will not exceed max_connections_per_host.
Default: 100
Deprecated:
This is no longer useful and does nothing. Expect this to be removed in a future release.
Sets the maximum number of requests processed by an IO worker per flush.
Default: 128
Deprecated:
This is no longer useful and does nothing. Expect this to be removed in a future release.
CassError cass_cluster_set_write_bytes_high_water_mark
(CassCluster * cluster, unsigned num_bytes )
Sets the high water mark for the number of bytes outstanding on a connection. Disables writes to a connection if the number of bytes queued exceed this value.
Default: 64 KB
Deprecated:
This is no longer useful and does nothing. Expect this to be removed in a future release.
Sets the low water mark for number of bytes outstanding on a connection. After exceeding high water mark bytes, writes will only resume once the number of bytes fall below this value.
Default: 32 KB
Deprecated:
This is no longer useful and does nothing. Expect this to be removed in a future release.
CassError cass_cluster_set_pending_requests_high_water_mark
(CassCluster * cluster, unsigned num_requests )
Sets the high water mark for the number of requests queued waiting for a connection in a connection pool. Disables writes to a host on an IO worker if the number of requests queued exceed this value.
Default: 256
Deprecated:
This is no longer useful and does nothing. Expect this to be removed in a future release.
CassError cass_cluster_set_pending_requests_low_water_mark
(CassCluster * cluster, unsigned num_requests )
Sets the low water mark for the number of requests queued waiting for a connection in a connection pool. After exceeding high water mark requests, writes to a host will only resume once the number of requests fall below this value.
Default: 128
Deprecated:
This is no longer useful and does nothing. Expect this to be removed in a future release.
Sets the timeout for connecting to a node.
Default: 5000 milliseconds
Sets the timeout for waiting for a response from a node.
Default: 12000 milliseconds
Sets the timeout for waiting for DNS name resolution.
Default: 2000 milliseconds
Sets the maximum time to wait for schema agreement after a schema change is made (e.g. creating, altering, dropping a table/keyspace/view/index etc).
Default: 10000 milliseconds
void cass_cluster_set_credentials
(CassCluster * cluster, const char * username, const char * password )
Sets credentials for plain text authentication.
void cass_cluster_set_credentials_n
(CassCluster * cluster, const char * username, size_t username_length, const char * password, size_t password_length )
Same as CassCluster::cass_cluster_set_credentials, but with lengths for string parameters.
Configures the cluster to use round-robin load balancing.
The driver discovers all nodes in a cluster and cycles through them per request. All are considered ‘local’.
CassError cass_cluster_set_load_balance_dc_aware
(CassCluster * cluster, const char * local_dc, unsigned used_hosts_per_remote_dc, cass_bool_t allow_remote_dcs_for_local_cl )
Configures the cluster to use DC-aware load balancing. For each query, all live nodes in a primary ‘local’ DC are tried first, followed by any node from other DCs.
Note: This is the default, and does not need to be called unless switching an existing from another policy or changing settings. Without further configuration, a default local_dc is chosen from the first connected contact point, and no remote hosts are considered in query plans. If relying on this mechanism, be sure to use only contact points from the local DC.
Deprecated:
The remote DC settings for DC-aware are not suitable for most scenarios that require DC failover. There is also unhandled gap between replication factor number of nodes failing and the full cluster failing. Only the remote DC settings are being deprecated.
CassError cass_cluster_set_load_balance_dc_aware_n
(CassCluster * cluster, const char * local_dc, size_t local_dc_length, unsigned used_hosts_per_remote_dc, cass_bool_t allow_remote_dcs_for_local_cl )
Same as CassCluster::cass_cluster_set_load_balance_dc_aware, but with lengths for string parameters.
Deprecated:
The remote DC settings for DC-aware are not suitable for most scenarios that require DC failover. There is also unhandled gap between replication factor number of nodes failing and the full cluster failing. Only the remote DC settings are being deprecated.
Configures the cluster to use token-aware request routing or not.
Important: Token-aware routing depends on keyspace metadata. For this reason enabling token-aware routing will also enable retrieving and updating keyspace schema metadata.
Default: cass_true (enabled).
This routing policy composes the base routing policy, routing requests first to replicas on nodes considered ‘local’ by the base load balancing policy.
void cass_cluster_set_token_aware_routing_shuffle_replicas
(CassCluster * cluster, cass_bool_t enabled )
Configures token-aware routing to randomly shuffle replicas. This can reduce the effectiveness of server-side caching, but it can better distribute load over replicas for a given partition key.
Note: Token-aware routing must be enabled for the setting to be applicable.
Default: cass_true (enabled).
Configures the cluster to use latency-aware request routing or not.
Default: cass_false (disabled).
This routing policy is a top-level routing policy. It uses the base routing policy to determine locality (dc-aware) and/or placement (token-aware) before considering the latency.
void cass_cluster_set_latency_aware_routing_settings
(CassCluster * cluster, cass_double_t exclusion_threshold, cass_uint64_t scale_ms, cass_uint64_t retry_period_ms, cass_uint64_t update_rate_ms, cass_uint64_t min_measured )
Configures the settings for latency-aware request routing.
Defaults:
- exclusion_threshold: 2.0
- scale_ms: 100 milliseconds
- retry_period_ms: 10,000 milliseconds (10 seconds)
- update_rate_ms: 100 milliseconds
- min_measured: 50
Sets/Appends whitelist hosts. The first call sets the whitelist hosts and any subsequent calls appends additional hosts. Passing an empty string will clear and disable the whitelist. White space is striped from the hosts.
This policy filters requests to all other policies, only allowing requests to the hosts contained in the whitelist. Any host not in the whitelist will be ignored and a connection will not be established. This policy is useful for ensuring that the driver will only connect to a predefined set of hosts.
Examples: “127.0.0.1” “127.0.0.1,127.0.0.2”
void cass_cluster_set_whitelist_filtering_n
(CassCluster * cluster, const char * hosts, size_t hosts_length )
Same as CassCluster::cass_cluster_set_whitelist_filtering, but with lengths for string parameters.
Sets/Appends blacklist hosts. The first call sets the blacklist hosts and any subsequent calls appends additional hosts. Passing an empty string will clear and disable the blacklist. White space is striped from the hosts.
This policy filters requests to all other policies, only allowing requests to the hosts not contained in the blacklist. Any host in the blacklist will be ignored and a connection will not be established. This policy is useful for ensuring that the driver will not connect to a predefined set of hosts.
Examples: “127.0.0.1” “127.0.0.1,127.0.0.2”
void cass_cluster_set_blacklist_filtering_n
(CassCluster * cluster, const char * hosts, size_t hosts_length )
Same as cass_cluster_set_blacklist_filtering_hosts(), but with lengths for string parameters.
Same as CassCluster::cass_cluster_set_whitelist_filtering, but whitelist all hosts of a dc
Examples: “dc1”, “dc1,dc2”
void cass_cluster_set_whitelist_dc_filtering_n
(CassCluster * cluster, const char * dcs, size_t dcs_length )
Same as CassCluster::cass_cluster_set_whitelist_dc_filtering, but with lengths for string parameters.
Same as CassCluster::cass_cluster_set_blacklist_filtering, but blacklist all hosts of a dc
Examples: “dc1”, “dc1,dc2”
void cass_cluster_set_blacklist_dc_filtering_n
(CassCluster * cluster, const char * dcs, size_t dcs_length )
Same as CassCluster::cass_cluster_set_blacklist_dc_filtering, but with lengths for string parameters.
Enable/Disable Nagle’s algorithm on connections.
Default: cass_true (disables Nagle’s algorithm).
void cass_cluster_set_tcp_keepalive
(CassCluster * cluster, cass_bool_t enabled, unsigned delay_secs )
Enable/Disable TCP keep-alive
Default: cass_false (disabled).
Sets the timestamp generator used to assign timestamps to all requests unless overridden by setting the timestamp on a statement or a batch.
Default: Monotonically increasing, client-side timestamp generator.
Requires Cassandra: 2.1+
void cass_cluster_set_connection_heartbeat_interval
(CassCluster * cluster, unsigned interval_secs )
Sets the amount of time between heartbeat messages and controls the amount of time the connection must be idle before sending heartbeat messages. This is useful for preventing intermediate network devices from dropping connections.
Default: 30 seconds
Sets the amount of time a connection is allowed to be without a successful heartbeat response before being terminated and scheduled for reconnection.
Default: 60 seconds
Sets the retry policy used for all requests unless overridden by setting a retry policy on a statement or a batch.
Default: The same policy as would be created by the function: CassRetryPolicy::cass_retry_policy_default_new. This policy will retry on a read timeout if there was enough replicas, but no data present, on a write timeout if a logged batch request failed to write the batch log, and on a unavailable error it retries using a new host. In all other cases the default policy will return an error.
Enable/Disable retrieving and updating schema metadata. If disabled this is allows the driver to skip over retrieving and updating schema metadata and CassSession::cass_session_get_schema_meta will always return an empty object. This can be useful for reducing the startup overhead of short-lived sessions.
Default: cass_true (enabled).
Enable/Disable retrieving hostnames for IP addresses using reverse IP lookup.
This is useful for authentication (Kerberos) or encryption (SSL) services that require a valid hostname for verification.
Default: cass_false (disabled).
CassError cass_cluster_set_use_randomized_contact_points
(CassCluster * cluster, cass_bool_t enabled )
Enable/Disable the randomization of the contact points list.
Default: cass_true (enabled).
Important: This setting should only be disabled for debugging or tests.
CassError cass_cluster_set_constant_speculative_execution_policy
(CassCluster * cluster, cass_int64_t constant_delay_ms, int max_speculative_executions )
Enable constant speculative executions with the supplied settings.
Disable speculative executions
Default: This is the default speculative execution policy.
CassError cass_cluster_set_max_reusable_write_objects
(CassCluster * cluster, unsigned num_objects )
Sets the maximum number of “pending write” objects that will be saved for re-use for marshalling new requests. These objects may hold on to a significant amount of memory and reducing the number of these objects may reduce memory usage of the application.
The cost of reducing the value of this setting is potentially slower marshalling of requests prior to sending.
Default: Max unsigned integer value
CassError cass_cluster_set_execution_profile
(CassCluster * cluster, const char * name, CassExecProfile * profile )
Associates a named execution profile which can be utilized during execution.
Note: Once the execution profile is added to a cluster, it is immutable and any changes made to the execution profile must be re-assigned to the cluster before a session connection is established in order for those settings to be utilized during query execution.
CassError cass_cluster_set_execution_profile_n
(CassCluster * cluster, const char * name, size_t name_length, CassExecProfile * profile )
Same as cass_cluster_add_execution_profile(), but with lengths for string parameters.
Prepare statements on all available hosts.
Default: cass_true
Enable the NO_COMPACT startup option.
This can help facilitate uninterrupted cluster upgrades where tables using COMPACT_STORAGE will operate in “compatibility mode” for BATCH, DELETE, SELECT, and UPDATE CQL operations.
Default: cass_false
Requires Cassandra: 3.0.16+ Requires Cassandra: 3.11.2+ Requires Cassandra: 4.0+