Category Archives: Uncategorized

Tweaked script to show top SQL by force matching signature

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

Posted in Uncategorized | 2 Comments

Outline Hint from dbms_xplan does not contain PARALLEL hint

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

Posted in Uncategorized | Leave a comment

Tuning Example With Outline Hints and SQL Profile

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

Posted in Uncategorized | Leave a comment

Two New ASH FORCE_MATCHING_SIGNATURE scripts

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

Posted in Uncategorized | 1 Comment

Plan Change Due to Index Partition Names Mismatch

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

Posted in Uncategorized | Leave a comment

MongoDB test server on Oracle Linux

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

Posted in Uncategorized | Leave a comment

Real World Index Example

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

Posted in Uncategorized | Leave a comment

Simple Index Example

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

Posted in Uncategorized | 1 Comment

Fixed Broken Links

I had a couple of new comments on older blog pages and I noticed that some links pointed to things which no longer exist. I fixed a few things that I knew were wrong. Finally, this week I decided to … Continue reading

Posted in Uncategorized | Leave a comment

SymPy Tutorial Repository

I have been playing with the Python SymPy package and created a repository with my test scripts and notes: https://github.com/bobbydurrett/sympytutorial Might be helpful to someone. I just got started. I had used Maxima before. SymPy and Maxima are both what … Continue reading

Posted in Uncategorized | Leave a comment