# cassandra Exceptions and Enums ### cassandra.\_\_version_info_\_ The version of the driver in a tuple format ### cassandra.\_\_version_\_ The version of the driver in a string format ### *class* cassandra.ConsistencyLevel Spcifies how many replicas must respond for an operation to be considered a success. By default, `ONE` is used for all operations. #### ANY *= 0* Only requires that one replica receives the write *or* the coordinator stores a hint to replay later. Valid only for writes. #### ONE *= 1* Only one replica needs to respond to consider the operation a success #### TWO *= 2* Two replicas must respond to consider the operation a success #### THREE *= 3* Three replicas must respond to consider the operation a success #### QUORUM *= 4* `ceil(RF/2) + 1` replicas must respond to consider the operation a success #### ALL *= 5* All replicas must respond to consider the operation a success #### LOCAL_QUORUM *= 6* Requires a quorum of replicas in the local datacenter #### EACH_QUORUM *= 7* Requires a quorum of replicas in each datacenter #### SERIAL *= 8* For conditional inserts/updates that utilize Cassandra’s lightweight transactions, this requires consensus among all replicas for the modified data. #### LOCAL_SERIAL *= 9* Like [`SERIAL`](#cassandra.ConsistencyLevel.SERIAL), but only requires consensus among replicas in the local datacenter. #### LOCAL_ONE *= 10* Sends a request only to replicas in the local datacenter and waits for one response. ### *class* cassandra.ProtocolVersion Defines native protocol versions supported by this driver. #### V3 *= 3* v3, supported in Cassandra 2.1–>3.x+; added support for protocol-level client-side timestamps (see [`Session.use_client_timestamp`](https://python-driver.docs.scylladb.com/stable/api/cassandra/cluster.md#cassandra.cluster.Session.use_client_timestamp)), serial consistency levels for [`BatchStatement`](https://python-driver.docs.scylladb.com/stable/api/cassandra/query.md#cassandra.query.BatchStatement), and an improved connection pool. #### V4 *= 4* v4, supported in Cassandra 2.2–>3.x+; added a number of new types, server warnings, new failure messages, and custom payloads. Details in the [project docs](https://github.com/apache/cassandra/blob/trunk/doc/native_protocol_v4.spec) #### V5 *= 5* v5, in beta from 3.x+. Finalised in 4.0-beta5 #### V6 *= 6* v6, in beta from 4.0-beta5 #### DSE_V1 *= 65* DSE private protocol v1, supported in DSE 5.1+ #### DSE_V2 *= 66* DSE private protocol v2, supported in DSE 6.0+ #### SUPPORTED_VERSIONS *= (5, 4, 3)* A tuple of all supported protocol versions for ScyllaDB, including future v5 version. #### BETA_VERSIONS *= (6,)* A tuple of all beta protocol versions #### MIN_SUPPORTED *= 3* Minimum protocol version supported by this driver. #### MAX_SUPPORTED *= 5* Maximum protocol version supported by this driver. #### *classmethod* get_lower_supported(previous_version) Return the lower supported protocol version. Beta versions are omitted. ### *class* cassandra.UserFunctionDescriptor(name, argument_types) Describes a User function by name and argument signature #### name *= None* name of the function #### argument_types *= None* Ordered list of CQL argument type names comprising the type signature #### *property* signature function signature string in the form ‘name([type0[,type1[…]]])’ can be used to uniquely identify overloaded function names within a keyspace ### *class* cassandra.UserAggregateDescriptor(name, argument_types) Describes a User aggregate function by name and argument signature #### name *= None* name of the aggregate #### argument_types *= None* Ordered list of CQL argument type names comprising the type signature #### *property* signature function signature string in the form ‘name([type0[,type1[…]]])’ can be used to uniquely identify overloaded function names within a keyspace ### *exception* cassandra.DriverException Base for all exceptions explicitly raised by the driver. ### *exception* cassandra.RequestExecutionException Base for request execution exceptions returned from the server. ### *exception* cassandra.Unavailable There were not enough live replicas to satisfy the requested consistency level, so the coordinator node immediately failed the request without forwarding it to any replicas. #### consistency *= None* The requested [`ConsistencyLevel`](#cassandra.ConsistencyLevel) #### required_replicas *= None* The number of replicas that needed to be live to complete the operation #### alive_replicas *= None* The number of replicas that were actually alive ### *exception* cassandra.Timeout Replicas failed to respond to the coordinator node before timing out. #### consistency *= None* The requested [`ConsistencyLevel`](#cassandra.ConsistencyLevel) #### required_responses *= None* The number of required replica responses #### received_responses *= None* The number of replicas that responded before the coordinator timed out the operation ### *exception* cassandra.ReadTimeout A subclass of [`Timeout`](#cassandra.Timeout) for read operations. This indicates that the replicas failed to respond to the coordinator node before the configured timeout. This timeout is configured in `cassandra.yaml` with the `read_request_timeout_in_ms` and `range_request_timeout_in_ms` options. #### data_retrieved *= None* A boolean indicating whether the requested data was retrieved by the coordinator from any replicas before it timed out the operation ### *exception* cassandra.WriteTimeout A subclass of [`Timeout`](#cassandra.Timeout) for write operations. This indicates that the replicas failed to respond to the coordinator node before the configured timeout. This timeout is configured in `cassandra.yaml` with the `write_request_timeout_in_ms` option. #### write_type *= None* The type of write operation, enum on [`WriteType`](https://python-driver.docs.scylladb.com/stable/api/cassandra/policies.md#cassandra.policies.WriteType) ### *exception* cassandra.CoordinationFailure Replicas sent a failure to the coordinator. #### consistency *= None* The requested [`ConsistencyLevel`](#cassandra.ConsistencyLevel) #### required_responses *= None* The number of required replica responses #### received_responses *= None* The number of replicas that responded before the coordinator timed out the operation #### failures *= None* The number of replicas that sent a failure message #### error_code_map *= None* A map of inet addresses to error codes representing replicas that sent a failure message. Only set when protocol_version is 5 or higher. ### *exception* cassandra.ReadFailure A subclass of [`CoordinationFailure`](#cassandra.CoordinationFailure) for read operations. This indicates that the replicas sent a failure message to the coordinator. #### data_retrieved *= None* A boolean indicating whether the requested data was retrieved by the coordinator from any replicas before it timed out the operation ### *exception* cassandra.WriteFailure A subclass of [`CoordinationFailure`](#cassandra.CoordinationFailure) for write operations. This indicates that the replicas sent a failure message to the coordinator. #### write_type *= None* The type of write operation, enum on [`WriteType`](https://python-driver.docs.scylladb.com/stable/api/cassandra/policies.md#cassandra.policies.WriteType) ### *exception* cassandra.FunctionFailure User Defined Function failed during execution #### keyspace *= None* Keyspace of the function #### function *= None* Name of the function #### arg_types *= None* List of argument type names of the function ### *exception* cassandra.RequestValidationException Server request validation failed ### *exception* cassandra.ConfigurationException Server indicated request errro due to current configuration ### *exception* cassandra.AlreadyExists An attempt was made to create a keyspace or table that already exists. #### keyspace *= None* The name of the keyspace that already exists, or, if an attempt was made to create a new table, the keyspace that the table is in. #### table *= None* The name of the table that already exists, or, if an attempt was make to create a keyspace, `None`. ### *exception* cassandra.InvalidRequest A query was made that was invalid for some reason, such as trying to set the keyspace for a connection to a nonexistent keyspace. ### *exception* cassandra.Unauthorized The current user is not authorized to perform the requested operation. ### *exception* cassandra.AuthenticationFailed Failed to authenticate. ### *exception* cassandra.OperationTimedOut The operation took longer than the specified (client-side) timeout to complete. This is not an error generated by Cassandra, only the driver. #### errors *= None* A dict of errors keyed by the [`Host`](https://python-driver.docs.scylladb.com/stable/api/cassandra/pool.md#cassandra.pool.Host) against which they occurred. #### last_host *= None* The last [`Host`](https://python-driver.docs.scylladb.com/stable/api/cassandra/pool.md#cassandra.pool.Host) this operation was attempted against. #### timeout *= None* The timeout value (in seconds) that was in effect when the operation timed out, or `None` if not applicable. #### in_flight *= None* The number of in-flight requests on the connection at the time of the timeout (includes orphaned requests), or `None` if not applicable.