Space Persistency

The SpaceClosed Where GigaSpaces data is stored. It is the logical cache that holds data objects in memory and might also hold them in layered in tiering. Data is hosted from multiple SoRs, consolidated as a unified data model. Persistency is provided via a component called External Data Source. This component provides persistency capabilities for the space architecture to interact with a persistency layer:

GigaSpaces Space Persistency provides the AbstractExternalDataSource class, which can be extended and then used to load and store data into an existing data source. Data is loaded from the data source during Space initialization, and from then onwards the application works directly with the Space.


Persistency can be configured to run in Synchronous or Asynchronous mode:

Synchronous persistency mode is deprecated and will be removed in a future GigaSpaces product release. Use Asynchronous Persistency mode instead.

The difference between Synchronous and Asynchronous persistency mode is the way that data is persisted back to the database. In Synchronous mode, data is persisted immediately after the operation is conducted where the client application waits for the ExternalDataSource to confirm the write. In Asynchronous mode (mirror Service), data is persisted in a reliable asynchronous manner using the mirror Service as a write-behind activity. This mode provides maximum performance.

Space Persistency API

The Space Persistency API contains an abstract class that should be extended in order to customize the Space persistency functionality. The ability to customize the Space persistency functionality allows GigaSpaces to interact with any external application or data source.

Client Call External Data Source Call Cache Policy Mode EDS Usage Mode
Write, Change, Take, WriteMultiple, TakeMultiple, Clear ExecuteBulk ALL_IN_CACHE, LRU read-write
Transaction Commit ExecuteBulk ALL_IN_CACHE, LRU read-write
Read, ReadMultiple, ReadById, ReadByIds, Count GetEnumerator LRU read-write,read-only
TakeMultiple GetEnumerator ALL_IN_CACHE, LRU read-write

For detailed API information, see the External Data Source API page.

GigaSpaces comes with a built-in implementation of AbstractExternalDataSource called NHibernate Space Persistency.

Refer to Space Persistency Initial Load for information on how to allow the Space to pre-load its data.