Re: [PHP] Best practices for using MySQL index
[email protected] (Aschwin Wesselius)
| Newsgroups | php.db,php.general |
|---|---|
| Message-ID | <[email protected]> |
Shelley wrote: >> Don't index just all integer fields. Keep track of the cardinality of a >> column. If you expect a field to have 100.000 records, but with only 500 >> distinct values it has no use to put an index on that column. A full record >> search is quicker. >> > > Hmmm... That's new. :) Well, to give you a good measure: keep the cardinality between 30 to 70-80 percent of your total records in a column. But sometimes your field is NULL or empty, so it really depends. You can't just put it into a standard configuration. And it also really depends on how many records a table contains etc. Besides that, benchmarking your development environment (you do have one do you?) can gives you a good idea on how your hardware and setup performs. Aschwin Wesselius