MySQL Troubleshooting

Testing Methods

Creating a minimal test case can confirm the problem, but you can do even more with it. The minimal test case makes it easy to pinpoint the reason for the problem. When you look at a JOIN that connects several tables with complicated WHERE conditions, it’s hard to say what exactly is wrong. But reducing the query to a couple of tables narrows the possibilities dramatically. Sometimes you fix the problem along the way when minimizing the query.

• Minimizing the test case usually reveals and fixes the problem.

In this section we’ll consider what to do if you create the test but can’t fix the issue on your own. There can be two reasons for this: a bug in the MySQL code or a misunderstanding of how some feature works. I’ll assume you already read the parts of the MySQL Reference Manual pertaining to the problem and found no answer. There are still some resources you can try.

Try the Query in a Newer Version

The reason for trying a newer version of MySQL is that, in case your problem was actually caused by a bug in the server, you may find that it’s already fixed. Installing and using a new version of MySQL might sound complicated. But if you followed my advice in Sandboxes and have a sandbox, it’s easy, especially if you use a minimal data set and combine the sandbox with your minimal test case.

Check for Known Bugs

If trying a newer version does not work, you can check the bug databases for known bugs. You could even consider searching for a bug report before you ...