MySQL

This post originally appeared over at Pythian. There are also some very smart comments over there that you shouldn’t miss, go take a look!

I spent some time last month getting up to speed on MySQL. One of the nice perks of working at Pythian is the ability to study during the workday. They could have easily said “You are an Oracle DBA, you don’t need to know MySQL. We have enough REAL MySQL experts”, but they didn’t, and I appreciate.

(This post originally appeared at the Pythian blog)

I’ve been following the discussion in various MySQL blogs regarding the sort_buffer_size parameters. As an Oracle DBA, I don’t have an opinion on the subject, but the discussion did remind me of many discussions I’ve been involved in. What’s the best size for SDU? What is the right value for OPEN_CURSORS? How big should the shared pool be?

All are good questions. Many DBAs ask them hoping for a clear cut answer – Do this, don’t do that! Some experts recognize the need for a clear cut answer, and if they are responsible experts, they will give the answer that does the least harm.

At the Percona Performance Conference in Santa Clara this week, the first question an audience member asked our panel was, "What is the most common performance problem you see in the field?"

I figured, being an Oracle guy at a MySQL conference, this might be my only chance to answer something, so I went for the mic. Here is my answer.

The most common performance problem I see is people who think there's a most-common performance problem that they should be looking for, instead of measuring to find out what their actual performance problem actually is.

It's a meta answer, but it's a meta problem. The biggest performance problems I see, and the ones I see most often, are not problems with machines or software. They're problems with people who don't have a reliable process of identifying the right thing to work on in the first place.

That's why the definition of Method R doesn't mention Oracle, or databases, or even computers. It's why Optimizing Oracle Performance spends the first 69 pages talking about red rocks and informed consent and Eli Goldratt instead of Oracle, or databases, or even computers.