Module org.eclipse.persistence.core
Package org.eclipse.persistence.annotations

Annotation Type HashPartitioning

@Target({TYPE,METHOD,FIELD}) @Retention(RUNTIME) public @interface HashPartitioning
HashPartitioning partitions access to a database cluster by the hash of a field value from the object, such as the object's location, or tenant. The hash indexes into the list of connection pools. All write or read request for object's with that hash value are sent to the server. If a query does not include the field as a parameter, then it can either be sent to all server's and unioned, or left to the sesion's default behavior.

Partitioning can be enabled on an Entity, relationship, query, or session/persistence unit. Partition policies are globally named to allow reuse, the partitioning policy must also be set using the @Partitioned annotation to be used.

Since:
EclipseLink 2.2
See Also:

  • Required Element Summary

    Required Elements
    Modifier and Type
    Required Element
    Description
    String
    name
    The name of the partition policy, names must be unique for the persistence unit.
    Column
    partitionColumn
    The database column or query parameter to partition queries by.

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    String[]
    connectionPools
    List of connection pool names to partition across.
    boolean
    unionUnpartitionableQueries
    Defines if queries that do not contain the partition field should be sent to every database and have the result unioned.

  • Element Details

    • name

      String name
      The name of the partition policy, names must be unique for the persistence unit.

    • partitionColumn

      Column partitionColumn
      The database column or query parameter to partition queries by. This is the table column name, not the class attribute name. The column value must be included in the query and should normally be part of the object's Id. This can also be the name of a query parameter. If a query does not contain the field the query will not be partitioned.

    • connectionPools

      String[] connectionPools
      List of connection pool names to partition across. Defaults to all defined pools in the ServerSession.
      Default:
      {}

    • unionUnpartitionableQueries

      boolean unionUnpartitionableQueries
      Defines if queries that do not contain the partition field should be sent to every database and have the result unioned.
      Default:
      false