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Re: Query that returns indexed fields involves FILESORT, why?
Posted by: Rick James
Date: March 01, 2010 01:16PM

Before you fall into the usual trap of poor performance by pagination via LIMIT, please read some of these (especially my responses):

Especially...,286632 (How do deletes and updates affect fetching of rows?),302536 (Slow inner join help!),260632 (3 Table Join (indexed) results in where-temp-filesort),239876,239913,291646 (Very Slow Simple Query)

Also...,355015 (Replication Delays in MySQL 5.1),291131 (Sorting with limit across a join. How to make it fast?),287643 (Data Modelling for an email table),286146 (Very high CPU utilisation with 40-50 concurrent connection on Innodb table),283204 (Best practices for multiple joins?),280159 (Load Balancing Database Server),280358 (Paged reading -- how? (LIMIT is slow)),261069 (MySql 4.1 optimization search poor performance)

Some discussion of pitfalls of SQL_CALC_FOUND_ROWS:,240838,241970,300253 (Query Pagination with LIMIT and total results),295760,296739,269950,270146

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Re: Query that returns indexed fields involves FILESORT, why?
March 01, 2010 01:16PM

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