Bloom filters and parallel execution
Today I want to share with you another interesting example of solving performance problem which happened in the database used for Business Intelligence purposes. Users were complaining that the performance in kind of staging database (STGDB) was much better than the production one (PRDDB), even…
Playing with statistics modification hints
How often did you have the situation when performance problem disappeared just after refreshing object statistics? Of course it is nice to solve the problem quickly and simply, but is always better to understand what has exactly happened. Recently I had such a problem and…
BP and Patch 22652097: set optimizer_adaptive_statistics to FALSE explicitly or it might not work!
Update 14.03.2018: After some exchanges with Nigel Bayliss, the behaviour described here has been filed as unpublished bug 27626925: OPTIMIZER ADAPTIVE STATS DEFAULT FALSE NOT HONORED WHEN ENABLED IN OCT OR JAN BP. It will be fixed starting with April’s bundle patch. According to…
Working with stateless session in hibernate and jpa
When doing heavy read-only operations in with the database it can be a good idea to take advantage of using Hibernate’s Stateless Session As it name indicates this session does not keep state of the entities that it retrieves from the database and so it…