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 126.96.36.199 to 188.8.131.52 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.