query cache: Attention with configuring Update Timestamps Cache region: expired entries cause wrong result sets! ---------------------------------------------------------------------------------------------------------------- Key: HHH-4550 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-4550 Project: Hibernate Core Issue Type: Improvement Components: caching (L2) Affects Versions: 3.3.2 Environment: 3.3.2 GA Reporter: Guenther Demetz Priority: Trivial Attachments: TestCaseQuryCache.jar When using hibernate's query cache (hibernate.cache.use_query_cache), then it's of fundamental importance to configure the Update Timestamps cache region in a way that his entries survive longer than the cached result sets in the Query cache region. Otherwise queries could return wrong (obsolete) result sets (See attached testcase). This is because the current UpdateTimestampsCache#isUpToDate implementation considers a result-set also as up-to-date, if there are no update-timestamps cached for the interested spaces (tables) at all. It if therefore important to notice that: 1- The Update-Timestamps-Cache-Region elements max-size should be configured higher than the number of tables you have on the db-schema, in manner that he can remember/hold the last update-timestamp for each table. 2- If you use any other eviction policy in the Update-Timestamps-Cache-Region, then you must assure that cached result sets in the Query-cache-region are evicted before relevant update-timestamps are going to be evicted. This fact should be clearly documented somewhere. Thanks G.D. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://opensource.atlassian.com/projects/hibernate/secure/Administrators.... - For more information on JIRA, see: http://www.atlassian.com/software/jira