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 though the dataset was exactly the same.
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.
If you have performance problems after migrating your BI databases from 18.104.22.168 to 22.214.171.124 or any other performance issue, you should not underestimate SQL Plan Notes, which can point you to the right direction or just let you understand what exactly is going on with your queries. Please check below how SQL Plan Notes helped me to investigate problem I recently encountered.
Dealing with query performance degradation coming from suboptimal execution plans is a task every DBA knows. Thanks to very good Oracle instrumentation, we have several options to deal with the problem, both in terms of analysis, as well as introducing the correct solution. If you are able to get the proper plan for example from
DBA_HIST_SQL_PLAN or from different “versions” of the same database available in various types of environments (DEV, TEST, etc.), your life should be much easier.
Originally posted on “Databases at CERN” blog
In my previous blog post (Migrating to Oracle Database 12c – what to do with auditing?) I provided you with number of reasons why unified auditing looks very promising and should be seriously considered while migrating to 12c. Nonetheless, I was not talking at all about performance – which also seems to be greatly improved.