Integrating EclipseLlink with EhCache to cache ReadAll and Native Queries

The problem at hand is that EclipseLink (great project lead by James Sutherland) does not use a query cache when dealing with ReadAll queries, i.e: all calls to getResultList() go to the database.  Some object-level caching is performed by avoiding construction of new objects based on the primary key values the database call returns.  EclipseLink compares the PK values returned by the getResultList() query to that in its identity cache and if matches are found, the cached objects are returned.  After running JProfiler, I determined that the saving weren't really significant at all as the query was being executed every time and only entity creation was avoided.   I realize that caching calls from getResultList() can be dangerous as changes from other applications will not be reflected, and that is the argument I received on the mailing list.  The argument carries merit, but since the default behavior of EclipseLink is to maintain an identity cache as described in the previous paragraph, any outside changes to non-primary key values will not be reflected anyway, so I don't see what the big deal about caching ReadAll queries really is. EclipseLink can't cache native queries since they aren't mapped nicely to JPA @Entity objects.  Since I'm working on a legacy system with a database design that resembles spaghetti and meatballs which also happens to be heavily used, I desperately n...

Date: June, 01 2010
Url: http://www.java.net/blog/zarar/archive/2010/05/31/integrating-eclipsellink-ehcache-cache-readall-and-native-queries

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