Cache_scheme and OracleConnectionPoolDataSource

Question

Hi guys.
I am implementing Oracle's OracleConnectionPoolDataSource to provide Connection Pooling. So far, so good. However, I also wanted to introduce the use of cache_scheme for optimising once we reach the max connections limit. Do I need to use OracleConnectionCacheImpl instead of OracleConnectionPoolDataSource in order to utilise cache_scheme ? Or does OracleConnectionPoolDataSource make use of this within it's own implementation ?
Thanks.
Steve.

Answer 1

Hi Dmitry,
     The behavior of the near cache depends on the invalidation startegy used. You can choose invalidation strategy by adding <invalidation-strategy> element to your <near-scheme> definition, and choosing one of the following four options:
     none -- typically used with the size and/or time limited front cache. The cache will not use events to evict items from the front cache.
     present -- a separate cache listener will be registered for each item in the front cache. That way front cache only receives the events for the items it cares about.
     all -- a single cache listener is registered that notifies front cache of any changes to the back cache. That means that it receives the events for all cache items, including those it doesn't care about (i.e. does not contain). On the other hand it helps keep the number of cache listeners low.
     auto -- currently same as all and default value if <invalidation-strategy> element is not specified.
     What you have to keep in mind when working with the near cache is that the front cache is only updated on gets, not on puts, unless invalidation strategy is set to none. If that wasn't the case, bulk load through the near cache would be problematic from the performance standpoint because of the large number of listener registrations (present) or the large number of events received (all).
     So, if you use time/size based expiration you can set invalidation strategy to none and items will be cached on the client side (front cache) on inserts. Otherwise, you should simply keep this difference in behavior in mind when working with the near cache.
     Finally, you should also be aware that queries against the near cache are simply passed through to the back cache and the results of the queries are not cached on the client side -- only subsequent gets will cache individual items.
     HTH,
     Aleks
     Message was edited by: aseovic