To configure an adapter service using the Query templateTo configure an adapter service using the Query templateField | Field Description/Action |
Keyspace Name | Specifies the keyspace which is auto-populated based on the created connection. |
Table Name | Specify the name of the table. |
icon to populate a single column in the table. You can use the 
icon to display all columns created in an existing table. Field | Description/Action |
Column Name | The column name in the table. |
Column Type | The column data type defined in the corresponding Column Name of the table. |
Type Definition | Specifies the string representation of Column Type. |
Output Field | The output field name. |
Output Field Type | The Java type that corresponds to the output field. |
Field | Description/Action |
Fetch Size | Limits the number of records for a table, if the records exceeds by the given size. The default value is -1. |
Allow Filtering | Provides the capability to query the clustering columns using any condition. |
Consistency Level | Defines to manage availability versus data accuracy. You can configure consistency for a session or per individual read or write operation. The write consistency levels in strongest-to-weakest order is given as follows:  ALL: Provides the highest consistency and the lowest availability of any other level.EACH QUORIUM: Maintains a strict consistency level at the same level, when used in multiple datacenter clusters.QUORIUM: Maintains a strong consistency across the cluster, when used in either single or multiple datacenter clusters. Use QUORIUM, if you can tolerate some level of failure.LOCAL QUORIUM: Maintains consistency locally. LOCAL QUORIUM is used in multiple datacenter clusters with a rack-aware replica placement strategy, such as (NetworkTopologyStatergy), and a properly configured snitch. Can be used with SimpleStrategy.LOCAL ONE: In a multiple datacenter clusters, the consistency level cross-DC traffic is not desirable when compared to the consistency level of ONE. LOCAL ONE accomplishes this. Use this consistency level in an offline datacenter to prevent automatic connection to online nodes in other datacenters if an offline node goes down.THREE: Satisfies the needs of most users because consistency requirements are not stringent.ANY: Provides low latency and a guarantee that a write never fails. Delivers the lowest consistency and highest availability.The read consistency levels in strongest-to-weakest order is given as follows: ALL: Provides the highest consistency of all levels and the lowest availability of all levels.QUORIUM: Maintains strong consistency across the cluster, when used in single or multiple datacenter clusters. Ensures strong consistency if you can tolerate some level of failure.LOCAL QUORIUM: Used in multiple datacenter clusters with a rack-aware replica placement strategy ( NetworkTopologyStrategy) and a properly configured snitch. Fails when used with SimpleStrategy.THREE: Provides the highest availability of all the levels if you can tolerate a comparatively high probability of stale data being read. The replicas contacted for reads may not always have the most recent write.LOCAL ONE: In a multiple datacenter clusters, the consistency level cross-DC traffic is not desirable when compared to the consistency level of ONE. LOCAL ONE accomplishes this. Use this consistency level in an offline datacenter to prevent automatic connection to online nodes in other datacenters if an offline node goes down.SERIAL: Use SERIAL to read the latest value of a column after a user has invoked a lightweight transaction to write to the column. Cassandra then checks the inflight lightweight transaction for updates and, if found, returns the latest data.LOCAL SERIAL: Used to achieve linearizable consistency for lightweight transactions. |
Limit | Limits the number of records to be retrieved by providing a definite value. |
Read Timeout in Millis | Specify the read time out value in milli seconds. This value is the amount of time Adapter for Apache Cassandra waits for the response from the Cassandra node to execute before stopping the Query service. |
Enabling Tracing | Define to enable and disable the tracing for transactions on all nodes in the cluster. Tracing is enabled to troubleshoot performance problems. |
icon to define the new WHERE clause fields. Name | Name Description/Action |
AND | The logical operator. |
Column | The name of the column you want to use in the WHERE clause. |
Operator | The following are the operators used: =<><=>=INCONTAINSCONTAINS KEY |
Input Field | The default value is ?, which acts as a placeholder for the variable so that you can set the input variable for that column at run time, or get input external to this adapter service. You can also type a fixed value in this field now or at run time. If you type a fixed value, be sure that it is valid, or an exception will be generated at run time. |
Field | Description/Action |
Parameter | The unique key for those rows in the above table which takes input at runtime. |
Column | The name of the column you need to use in the WHERE clause. |
CQL Type | The CQL data type defined in the corresponding Column Name of the table. |
Input Field Type | The corresponding data type of the Input Field. |
Input Field | The name of the input field. By default the name combines the values of Parameter and Column fields. However, you can also choose to specify any custom value. |
Field | Description/Action |
Column Name | Displays the columns which contains only the cluster key type. |
Sort Order | Displays the records in correct ascending or descending order. Select either ASC or DES. By default, ASC is selected. |