Java Persistence API (JPA) Extensions Reference for EclipseLink,
Release 2.4 |
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Use @RoundRobinPartitioning to send requests in a "round robin" fashion to the set of connection pools.
Annotation Elements
Table 2-62 describes this annotation's elements.
Table 2-62 @RoundRobinPartitioning Annotation Elements
| Annotation Element | Description | Default |
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(Required) Name of the partition policy. Names must be unique for the persistence unit. |
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(Optional) List of connection pool names to load balance across. |
All defined pools in the |
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(Optional) This allows for a set of database to be written to and kept in sync, and have reads load-balanced across the databases. |
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Usage
Use the @RoundRobinPartitioning annotation for load-balancing read queries across a cluster of database machines. Using @RoundRobinPartitioning requires that the full database be replicated on each machine.
The data should either be read-only, or writes should be replicated on the database.
The persistence unit properties support adding named connection pools in addition to the existing configuration for read/write/sequence. A named connection pool must be defined for each node in the database cluster.
If a transaction modifies data from multiple partitions, you should use JTA ensure proper two-phase commit of the data. You can also configure an exclusive connection in the EntityManager to ensure that only a single node is used for a single transaction.
Examples
See "@Partitioned" for an example of partitioning with EclipseLink.
See Also
For more information, see:
