Author Archives: Bobby

We had an application that created 500,000 tables and 500,000 sequences and the vendor sent us a cleanup script that we thought would drop the tables but not the sequences. It took us a few attempts to get a cleanup … Continue reading →

I have been working hard on an issue that happened after we patched an Oracle database to the 19.13 patch set which just came out in October. The application experienced a ton of latch: shared pool waits, and the patch … Continue reading →

I just finished another production tuning exercise that is like two recent posts: Two New ASH FORCE_MATCHING_SIGNATURE scripts Tuning Example With Outline Hints and SQL Profile The biggest new thing was that I ran the ashtopelapsed.sql script that I mentioned … Continue reading →

I was tuning a parallel query and was a little surprised to find that an outline hint from EXPLAIN PLAN and dbms_xplan.display did not contain a PARALLEL hint. So, a query I was testing did not run in parallel with … Continue reading →

I tuned a production query this week using outline hints and a SQL profile. This is like other examples I have posted but may have enough differences to be worth documenting here. A query in a batch job was taking … Continue reading →

I just put two new scripts on my OracleDatabaseTuningSQL GitHub repository. These came out of a PeopleSoft Financials performance problem I was working on that involved a lot of similar SQL statements that used constants instead of bind variables, so … Continue reading →

I want to document a bug I ran across in Oracle 11.2.0.3 on HP-UX Itanium and how it caused unexpected plan changes that would bring the database to its knees with many long running queries running the bad plan. I … Continue reading →

I use Oracle Enterprise Linux on VirtualBox running on my Windows 10 laptop for test servers (virtual machines) of various types of software. I just setup a MongoDB VM yesterday and thought I would document some of the things I … Continue reading →

This is a follow up to my previous post with a real world example of how much difference indexes can make on tables that do not have them. I looked at an AWR report of a peak hour on a … Continue reading →

There is a lot to be said about when to add indexes on Oracle tables, but I wanted to show a simple example. In this case we have a table with no indexes and a query with two equal conditions … Continue reading →