… need to help it out with optimizer hints like straight_join to have it look at tables in the right order… alluding to lots of single column indexes generally aren’t a good idea, well MySQL forces this upon you if you actually… create the following indexes: unique index on order_id index on item_type_id index on locale_id index on currency_id index on operator_id…
Comment: MySQL VIEW as performance troublemaker
February 16, 2013 By 57 Comments
… as a macro? And can one dictate the view to force it to run as a macro then to use the… view worked fine. Joined one more table and all hell broke loose! The select statement was almightily indexed for instant execution. The… the db server. The view did nothing. Removed the newly joined table and created the view again. The view was meant…
Comment: Star Schema Bechmark: InfoBright, InfiniDB and LucidDB
January 10, 2010 By 48 Comments
… the conclusions. – MonetDB does *not* limit (hash) index sizes to the available memory. It will … to add an ALTER statement after a brute force quick load. A basic assumption for any …will be more disk space conservative, outer-memory-joins are based on sort-merge, increased intra-query parallelism…
Post: A micro-benchmark of stored routines in MySQL
August 16, 2009 By 7 Comments
…’m writing here are deliberately mis-optimized to force a bad execution plan. You should never use … select distinct co.Code from Country as co inner join CountryLanguage as cl on cl.CountryCode = co.Code…. The query can’t be optimized to use indexes, and the stored function is opaque to the optimizer…
Post: MySQL caching methods and tips
April 4, 2011 By 5 Comments
… a possible solution to the problem. This forces one query to do the computation while … bottleneck is eliminated, the sorting, aggregation and join operations are still CPU intensive and single threaded…be fast to access, since it can be indexed appropriately for your queries. Using INSERT .. SELECT …
Comment: How much overhead is caused by on disk temporary tables
August 17, 2007 By 26 Comments
…for making users writing bad SQL to suffer instead of forcing to use ORDER BY NULL if you want results …, e.id , sum(q.score) score FROM exam e INNER JOIN question q ON e.id = q.exam_id GROUP …unique). So ironically, although MySQL could in principle use the index on the id column to do a pretty fast …
