I was researching some JDBC Oracle Connection Pooling items and came across a new(er) Oracle Pool implementation called Universal Connection Pool (UCP). Now this uses a new class, PoolDataSource, for connection pooling rather then the OracleDataSource [with the cache option enabled]. I am debating whether to switch to this new implementation but can't find any good documentation of what (if any) fixes/upgrades this would buy me. Anyone have an experience with both? Pluses/Minuses? Thanks.
8 Answers
I did an extensive evaluation of UCP and decided to NOT use UCP - please have a look at this post for details.
I tested the UCP and deployed it to production in a Spring 3.0.5 Hibernate app using Spring JMS listener containers and Spring-managed sessions and transactions using the @Transactional annotation. The data sometimes causes SQL constraint errors, due to separate listener threads trying to update the same record. When that happens, the exception is thrown by one method annotated by @Transactional and the error is logged into the database using another method annotated by @Transactional. For whatever reason, this process seems to result in a cursor leak, that eventually adds up and triggers the ORA-01000 open cursor limit exceeded error, causing the thread to cease processing anything.
OracleDataSource running in the same code doesn't seem to leak cursors, so it doesn't cause this problem.
This is a pretty weird scenario, but it indicates to me that it's a little too early to be using the UCP in an application with this kind of structure.
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