So, I mentioned before that I found out about index_merge at the MySQL Conference. I was wondering why I had not heard more about it since it came out in 5.0.3. When talking with some MySQL people about it, I received mixed results. So, I decided to kind of run my own tests on some data and see what I could figure out.
I apologize for WordPress’ bad output. =(
The Data
I created a table with 5 million rows. Early tests with MySQL’s Harrison Fisk (HarrisonF) over my shoulder with small data sets showed MySQL would optimize out the indexes in favor of table scans. I wanted to avoid that. This is my table schema:
CREATE TABLE `test2` (
`id1` int(10) unsigned NOT NULL default ‘0′,
`id2` int(10) unsigned NOT NULL default ‘0′,
`id3` int(10) …