I was there in the meetup and my feeling was a mix about the same. It was nice to have Kaj here (for the first time) and listen to him about Sun's acquisition. On the other hand it was disheartening to see so few people from corporates turning up. It was almost negligible. I'm still positive on this and do expect many more people to turn up. There were a total of three talks in the meet and then we had some chit chat with people. In his first talk, Kaj first greeted everybody in Hindi, Tamil and Kannada and many were delighted. Kaj touched various aspects of Sun's acquisition and also their on-boarding struggle. He also mentioned about MySQL considering Sun's liberal SCA in place of their stricter CLA. (I haven't gone through SCA to actually comment on it's benefits) Second talk by Thava was on how to contribute code to MySQL. It was a nice talk and showed various resource points and steps of doing so in a right manner. Third talk, again by Kaj, was on the different ways of contributing to MySQL and MySQL community other than code. He showed screenshots of forums, forge, planetmysql, few blogs (he forgot mine ;) ), bugs.mysql and how to use them. Interestingly, my name appeared on the planetmysql page :) . Overall it was nice that it started and we need to find out ways for more participation.
Wednesday, July 30, 2008
Friday, May 30, 2008
Variable's Day Out #14: log_queries_not_using_indexes
Properties:
| Applicable To | MySQL Server |
| Server Startup Option | --log-queries-not-using-indexes |
| Scope | Global |
| Dynamic | Yes |
| Possible Values | Boolean |
| Default | False |
| Category | Performance, Monitoring, Best Practices |
Description:
If you have slow query logs enabled (with --log-slow-queries), this variable will help interpret all those queries that are not using indexes as slow queries.
Usage:
While designing a MySQL oriented application, I generally design my schema first without introducing any index (only exception being the PRIMARY ones). Get the application ready. Next enable log_queries_not_using_indexes and start index usage testing. Analyze all queries, introduce indexes one by one and you are all set to go. This helps a lot in rewriting queries, figuring out the best possible index etc. Many times I have seen the need for swapping WHERE clause CONDITIONS for making it possible for the query to use an existing index.
For already deployed systems' performance glitches and production outages, this flag do serve as a starting point.
Though as always, usage of a variable is subject to circumstances. For my conditions and usage pattern, this variable comes very handy.
Read more:
Hope you enjoyed reading this.
