Author Archives

SQL Developer: Viewing Trace Files

Just a quick plug for looking at raw sql trace files via SQL Developer.
There is a nice Tree View:

Which can be expanded:

Also summary view of statistics, filterable:

And a list view, filterable and orderable:

Some sort of right click summary for b…

Real time sql monitoring – bulk bound statement

Moving through some observations of an ongoing investigation tackling the easiest ones first.
Previously I observed the slow execution of a recursive delete of statistics history but coming not from MMON but from a number of application processes which…

COUNT STOPKEY – NVL

Yesterday I mentioned issues with a recursive delete operation on statistics history.
This is a quick illustration of the last points I made on that post regarding the lack of a COUNT STOPKEY optimisation because of the use of NVL.
COUNT STOPKEY is an …

Understanding vs Resolution – Statistics History Cleanup

Today I helped resolve a problem quickly but to the detriment of my understanding of exactly what was going on and why.
And as part of the quicker resolution, I had to destroy the evidence which would have helped understand better.
So… now need t…

DBMS_STATS.PURGE_STATS

Prior to 11.2.0.4, DBMS_STATS.PURGE_STATS does a slow delete of stats before the parameterised input timestamp.
Why might you be purging? Here’s one such illustration:
https://jhdba.wordpress.com/tag/dbms_stats-purge_stats/
This delete can be slo…