Graph frequently executed SQL by FORCE_MATCHING_SIGNATURE

I made a new graph in my PythonDBAGraphs program. Here is an example with real data but the database name blanked out:

sql_matching_group_of_signatures_blog

My graphs are all sized for 1920 x 1080 monitors so I can see all the detail in the lines using my entire screen. The idea for this graph is to show how the performance of the queries that matter to the users changes as we add more load and data to this (more...)

Understanding query slowness after platform change

We are moving a production database from 10.2 Oracle on HP-UX 64 bit Itanium to 11.2 Oracle on Linux on 64 bit Intel x86. So, we are upgrading the database software from 10.2 to 11.2. We are also changing endianness from Itanium’s byte order to that of Intel’s x86-64 processors. Also, my tests have shown that the new processors are about twice as fast as the older Itanium CPUs.

Two SQL (more...)

Comparing Common Queries Between Test and Production

The developers complained that their test database was so much slower than production that they could not use it to really test whether their batch processes would run fast enough when migrated to production. They did not give me any particular queries to check. Instead they said that the system was generally too slow. So, I went through a process to find SQL statements that they had run in test and that normally run in production (more...)

Jonathan Lewis

I am finally getting around to finishing my four-part blog series on people who have had the most influence on my Oracle performance tuning work. The previous three people were Craig ShallahamerDon Burleson, and Cary Millsap. The last person is Jonathan Lewis. These four people, listed and blogged about in chronological order, had the most influence on my understanding of how to do Oracle database performance tuning. There are many other great (more...)

Log file parallel write wait graph

I got a chance to use my onewait Python based graph to help with a performance problem. I’m looking at slow write time from the log writer on Thursday mornings. Here is the graph with the database name erased:

log_file_parallel_write_waits

We are still trying to track down the source of the problem but there seems to be a backup on another system that runs at times that correspond to the spike in log file parallel write (more...)

Python DBA Graphs Github Repository

I decided to get rid of the Github repository that I had experimented with and to create a new one. The old one had a dump of all my SQL scripts but without any documentation. But, I have updated my Python graphing scripts a bit at a time and have had some recent value from these scripts in my Oracle database tuning work. So, I created a Github repository called PythonDBAGraphs. I think it will (more...)

Another SQL Profile to the rescue!

We have had problems with set of databases over the past few weeks. Our team does not support these databases, but my director asked me to help. These are 11.2.0.1 Windows 64 bit Oracle databases running on Windows 2008. The incident reports said that the systems stop working and that the main symptom was that the oracle.exe process uses all the CPU. They were bouncing the database server when they saw this behavior (more...)

Math Resources

I feel like I have not been posting very much on this blog lately. I have been focused on things outside of Oracle performance so I haven’t had a lot of new scripts to post.  I have been quietly updating my Python source code on GitHub so check that out. I have spent a lot of time educating myself in various ways including through the leadership and communication training program that comes from Toastmasters. My new (more...)

General troubleshooting lessons from recent Delphix issue

Delphix support helped me resolve an issue yesterday and the experience gave me the idea of writing this post about several general computer issue troubleshooting tips that I have learned down through the years. Never mind that I ignored these lessons during this particular problem. This is more of a “do as I say” and not a “do as I do” story.  Actually, some times I remember these lessons. I didn’t do so well this (more...)

Cloning 10.2.0.3 Oracle Home on fully patched 11.31 HP-UX hangs

I based this blog post on information that I learned from this Oracle Support document:

Runinstaller And Emctl Do Not Work After Upgrading HP-UX 11.31 To 11.31 Update3 (Sep 2008) (Doc ID 780102.1)

My situation was slightly different from what Oracle’s note describes so I thought it would be helpful to document what I found.

In my case I am cloning an Oracle 10.2.0.3 home on to a fully (more...)