org.apache.cassandra.db

## Class SizeEstimatesRecorder

- java.lang.Object
- - org.apache.cassandra.service.MigrationListener
  - - org.apache.cassandra.db.SizeEstimatesRecorder

- All Implemented Interfaces:
    java.lang.Runnable

      public class SizeEstimatesRecorder
      extends MigrationListener
      implements java.lang.Runnable

  A very simplistic/crude partition count/size estimator. Exposing per-primary-range estimated partitions count and size in CQL form, as a direct CQL alternative to Thrift's describe_splits_ex(). Estimates (per primary range) are calculated and dumped into a system table (system.size_estimates) every 5 minutes. See CASSANDRA-7688.

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static SizeEstimatesRecorder` | `instance`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `onDropColumnFamily(java.lang.String keyspace, java.lang.String table)`
    `void` | `run()`

    - ### Methods inherited from class org.apache.cassandra.service.MigrationListener

      `onCreateAggregate, onCreateColumnFamily, onCreateFunction, onCreateKeyspace, onCreateUserType, onCreateView, onDropAggregate, onDropFunction, onDropKeyspace, onDropUserType, onDropView, onUpdateAggregate, onUpdateColumnFamily, onUpdateFunction, onUpdateKeyspace, onUpdateUserType, onUpdateView`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### instance

          public static final SizeEstimatesRecorder instance

  - ### Method Detail

    - #### run

          public void run()

      Specified by:
        `run` in interface `java.lang.Runnable`

    - #### onDropColumnFamily

          public void onDropColumnFamily(java.lang.String keyspace,
                                         java.lang.String table)

      Overrides:
        `onDropColumnFamily` in class `MigrationListener`

Copyright © 2018 The Apache Software Foundation