QueryCassandra

Description:

Execute provided Cassandra Query Language (CQL) select query on a Cassandra 1.x, 2.x, or 3.0.x cluster. Query result may be converted to Avro or JSON format. Streaming is used so arbitrarily large result sets are supported. This processor can be scheduled to run on a timer, or cron expression, using the standard scheduling methods, or it can be triggered by an incoming FlowFile. If it is triggered by an incoming FlowFile, then attributes of that FlowFile will be available when evaluating the select query. FlowFile attribute 'executecql.row.count' indicates how many rows were selected.

Tags:

cassandra, cql, select

Properties:

In the list below, the names of required properties appear in bold. Any other properties (not in bold) are considered optional. The table also indicates any default values, whether a property supports the NiFi Expression Language, and whether a property is considered "sensitive", meaning that its value will be encrypted. Before entering a value in a sensitive property, ensure that the nifi.properties file has an entry for the property nifi.sensitive.props.key.

NameDefault ValueAllowable ValuesDescription
Cassandra Contact PointsContact points are addresses of Cassandra nodes. The list of contact points should be comma-separated and in hostname:port format. Example node1:port,node2:port,.... The default client port for Cassandra is 9042, but the port(s) must be explicitly specified.
Supports Expression Language: true (will be evaluated using variable registry only)
KeyspaceThe Cassandra Keyspace to connect to. If not set, the keyspace name has to be provided with the table name in the form of <KEYSPACE>.<TABLE>
Supports Expression Language: true (will be evaluated using variable registry only)
SSL Context ServiceController Service API:
SSLContextService
Implementations: StandardRestrictedSSLContextService
StandardSSLContextService
The SSL Context Service used to provide client certificate information for TLS/SSL connections.
Client AuthREQUIRED
  • WANT
  • REQUIRED
  • NONE
Client authentication policy when connecting to secure (TLS/SSL) cluster. Possible values are REQUIRED, WANT, NONE. This property is only used when an SSL Context has been defined and enabled.
UsernameUsername to access the Cassandra cluster
Supports Expression Language: true (will be evaluated using variable registry only)
PasswordPassword to access the Cassandra cluster
Sensitive Property: true
Supports Expression Language: true (will be evaluated using variable registry only)
Consistency LevelONE
  • ANY
  • ONE
  • TWO
  • THREE
  • QUORUM
  • ALL
  • LOCAL_QUORUM
  • EACH_QUORUM
  • SERIAL
  • LOCAL_SERIAL
  • LOCAL_ONE
The strategy for how many replicas must respond before results are returned.
Character SetUTF-8Specifies the character set of the record data.
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
CQL select queryCQL select query
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Max Wait Time0 secondsThe maximum amount of time allowed for a running CQL select query. Must be of format <duration> <TimeUnit> where <duration> is a non-negative integer and TimeUnit is a supported Time Unit, such as: nanos, millis, secs, mins, hrs, days. A value of zero means there is no limit.
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Fetch size0The number of result rows to be fetched from the result set at a time. Zero is the default and means there is no limit.
Supports Expression Language: true (will be evaluated using variable registry only)
Output FormatAvro
  • Avro
  • JSON
The format to which the result rows will be converted. If JSON is selected, the output will contain an object with field 'results' containing an array of result rows. Each row in the array is a map of the named column to its value. For example: { "results": [{"userid":1, "name":"Joe Smith"}]}

Relationships:

NameDescription
retryA FlowFile is transferred to this relationship if the operation cannot be completed but attempting it again may succeed.
successA FlowFile is transferred to this relationship if the operation completed successfully.
failureA FlowFile is transferred to this relationship if the operation failed.

Reads Attributes:

None specified.

Writes Attributes:

NameDescription
executecql.row.countThe number of rows returned by the CQL query

State management:

This component does not store state.

Restricted:

This component is not restricted.

Input requirement:

This component allows an incoming relationship.

System Resource Considerations:

None specified.