Python Practice Produced Pretty Pictures

I wrote a Python program that made some fun pictures so I thought I would share them even though this is not really a database post.

I practice Python programming by doing Rosetta Code programming tasks that no one has implemented in Python. This is a fun way of keeping up my Python skills. My most recent contribution made pretty pictures so I thought I would show them here. The code takes a cube and (more...)

Speed of Light

Looking at cloud databases has me thinking about the speed of light. Wikipedia says that the speed of light is about 186,000 miles per second. If my calculations are correct that is 5.37 microseconds per mile. The United States is about 2680 miles wide so it would take light about 14.4 milliseconds to cross the US. If I ping one of my favorite web sites it takes tens of milliseconds to ping so (more...)

New utility Python scripts for DBAs

I pushed out three new Python scripts that might be helpful to Oracle DBAs. They are in my miscpython repository.

Might be helpful to some people.


Slides from March AZORA meeting

Here are the slides from our March Arizona Oracle User Group (AZORA) meeting:

Daniel Morgan Security Master Class

We really appreciate Daniel Morgan taking the time to share this information about the increasingly important topic of database security.

Also, AZORA is always looking for people to present at future meetings. We have one more meeting in May before the blazing hot Arizona summer and then we start up again in September. Email be at bobby@bobbydurrettdba. (more...)

Oracle Database Security Master Class AZORA Meetup Thursday

Next Thursday Daniel Morgan from TidalScale will be giving a free Oracle Database Security Master Class for our March Arizona Oracle User Group meeting. See the details in our Meetup link:

ORA-30926 on MERGE statement

I was on call last week and I got a ticket about a batch job that was failing on a MERGE statement with an ORA-30926 error. Our support team worked around it by deleting some duplicate rows in a table that was feeding into the MERGE. This week I wanted to go back and try to understand what would cause ORA-30926 errors on MERGE statements.

I read through some blog posts and Oracle support documents (more...)

One query in MySQL Performance Schema

I am learning about MySQL performance tuning. I read the Performance Schema chapter of the MySQL 5.7 manual and I have a MySQL 5.7.20 database running under Linux. I have a test table and I am running a simple query that does a full scan of the table and returns the sum of a couple of columns. The goal was to look at some Performance Schema tables to see what they would (more...)

SQL Profile not used on slightly different query

Last week I was asked to help with a performance problem that looked a lot like a problem I fixed in July with a SQL Profile. The query whose plan I fixed back in July was modified by a minor application change over the weekend. A single column that was already in the select clause was added to another part of the select clause. As a result, the SQL_ID for the new query was different (more...)

Slides From January 2019 AZORA Meeting

Here are slides from the January 2019 AZORA Meeting with Charles Kim and Viscosity:

Oracle Database 12.2 New Features

Oracle Database 18c New Features

Thank you to Charles and Viscosity for making our meeting a big success, and thanks for sharing these slides.


MIT’s Free Algorithms Track

MIT, the Massachusetts Institute of Technology, has published a free set of three undergraduate level Algorithms classes that I recommend to the readers of this blog. These are links to the three classes in the order that they should be taken.

Mathematics for Computer Science (Spring 2015)

Introduction to Algorithms (Fall 2011)

Design and Analysis of Algorithms (Spring 2015)

I took the 2010 version of the Mathematics for Computer Science class and I am (more...)