Comments on: Refactoring MySQL Applications: Part 1

By: Log Buffer #131: a Carnival of the Vanities for DBAs

Log Buffer #131: a Carnival of the Vanities for DBAs — Fri, 16 Jan 2009 17:22:42 +0000

[...] « Refactoring MySQL Applications: Part 1 [...]

By: Nicklas Westerlund

Nicklas Westerlund — Fri, 16 Jan 2009 14:04:58 +0000

@Dado, yes, it would, as in the index (manufacturer,category) doing a search on WHERE manufacturer=’Apple’ would form a prefix of the index, and it could be utilized. (however, not WHERE category=’Electronics’)

Depends on what you want to find, but in theory you should be able to catch queries not using indexes (although there may be valid reasons for not doing so) by using log-queries-not-using-indexes

By: Dado

Dado — Fri, 16 Jan 2009 09:00:56 +0000

Hi, just to check: if I rewrote WHERE category=’Electronics’ AND manufacturer=’Apple’) to WHERE manufacturer=’Apple’ AND category=’Electronics’) and redid the index as (manufacturer, category), it’d work with WHERE manufacturer=’Apple’ too?

Is there a way to automagically find these kind of stuff from the logs?