By Franck Pachot . In a previous post about Result Cache, I was using ‘set autotrace on’ in my session to see when the result cache hit saves the logical reads. I got a comment, by e-mail and with full test case, mentioning that the invalidation I had when doing some DML does not occur when autotrace is set to…
By Franck Pachot . I encountered recently a case where result cache was incorrectly used, leading to high contention when the application encountered a peak of load. It was not a surprise when I’ve seen that the function was called with an ‘ID’ as argument, which may have thousands of values in this system. I mentioned to the software vendor…
By Franck Pachot . During the execution of a SQL statement, you cannot guess how many times an operation, a predicate, or a function will be executed. This depends on the execution plan, on some caching at execution, and some other execution time decisions. Here is an example where result cache may bring some overhead by calling a function multiple…
By Franck Pachot . At our bi-annual dbiXchange I was talking with Nicolas Jardot about his presentation on Result Cache (don’t forget Jérome witt session about RC at DOAG) where he has shown an unexpected behavior on ‘fetch first n rows queries’. That behavior – if it is not a bug – can also be a good thing when using…
Oracle has introduced three new caching features in its Oracle 11g release:
In this posting, I will present the query result cache feature.
