MySQL – No Index Used With ORDER BY + LIMIT and DISTINCT. This is actually a follow up on my previous post. Developers tried to rewrite all statements and even overdid it. As we say in Russia – “teach fool how to pray and he will break his forehead”.
Doug Burns posted photos with his new teammates on his blog, and I felt they deserved a mention here too.
Robert Treat has published the 27th edition of Log Buffer, the weekly review of database blogs, on zillablog.
Filesorts and temp tables are a necessary evil in MySQL, used when MySQL must sort the data before returning the output to the user. They are the most common issue with slow queries in MySQL, the main reason being that if the output is too large, you can kiss goodbye in-memory performance, and say hello to disk access.
Read Gary Krakow’s review of SanDisk’s 32GB, 1.8-inch solid-state drive (SSD)
Oracle 10.2.0.3 Patchset – Known Issues and Bugs. Oracle 10.2.0.3 patchset is not functional on Solaris SPARC 64bit platform with datafiles on Veritas VxFS.
Today is the first time I had to look at MySQL performance. Tiny database as web application back-end was having significant performance issues with spikes of CPU workload. After identifying problematic queries, I found a pile of statements using IN subqueries. I asked around and our MySQL experts assured me that this is one of the minor and not so disturbing issues, in fact. I can’t imagine what those disturbing issue are. I guess Oracle XE does have some advantages over MySQL for small installations.
Doug Burns is finally here in Ottawa. You must see his smile in the airport – somehow he managed to read my comment and already expected me while I thought it would be surprise.
Steve Karam, the Oracle Alchemist, has published the 26th edition of Log Buffer, the weekly review of database blogs.
To the subject at hand (psst, there will be some technical stuff in the end)… A few days ago I came across Twitter. I liked that idea very much and even tried it for one evening. I don’t think Twitter fits my lifestyle, but I recognized a very familiar concept. Indeed, it reminds me of one feature of our Pythian Support Track. Time for a bit of technical stuff…since we are mostly talking about databases on this blog, here is a view in Oracle I found very useful one day: SYSTEM_PRIVILEGE_MAP.