…time reads when you want to have 100% guaranty you’re reading latest data. Second…cache Memory is much faster than disk and you generally want to have data you’re accessing to be cached in memory by MySQL cache…running queries. That is all for today but far from being all what can be said about MySQL…
Post: Getting real life query speeds with MySQL
January 10, 2007 By 10 Comments
…second and further runs, especially when it comes to disk IO workloads. The attempt to fix it is often using SELECT SQL_NO_CACHE or disabling QueryCache for the test. This works by blocking query cache but still repeated runs execute much faster…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 28 Comments
…running silly queries that do nothing but cause buffer hits, skewing the result towards “this ratio looks great!” The second kind of time…cache hit to be faster than a miss. Hard-to-prove assumption #2: A key cache…
Post: To SQL_CALC_FOUND_ROWS or not to SQL_CALC_FOUND_ROWS?
August 28, 2007 By 57 Comments
…runs. And now – we need too check how long our COUNT query would take: mysql> SELECT SQL_NO_CACHE…seconds for SQL_CALC_FOUND_ROWS. 7+7 seconds in case when two queries used. Filesort: 1.8 seconds…
Post: How much overhead is caused by on disk temporary tables
August 16, 2007 By 26 Comments
…time which takes fraction of second to do, but it is not how it happens in practice. mysql…query runs) which does not make sense as there no…times faster than disk based MyISAM tables Hopefully MySQL will implement support of dynamic rows for MEMORY tables some time…
Post: InnoDB vs MyISAM vs Falcon benchmarks - part 1
January 8, 2007 By 117 Comments
…second goal of benchmark was a popular myth that MyISAM is faster…cache size : 4096 KB 16GB of RAM MySQL version We used MySQL 5.1.14-beta sources for MyISAM / InnoDB and MySQL…queries. InnoDB is better than MyISAM by 2-26 times and than Falcon by 1.64 – 3.85 times. READ_PK_RANGE_INDEX Query…
Post: The MySQL optimizer, the OS cache, and sequential versus random I/O
April 28, 2008 By 17 Comments
…query completion time, I wrote…faster one? That’s what this post is about. Let’s start with the MySQL query… the operating system cache, or whether it’ll …query will run for days and never complete. No one ever let it finish to see how long it would run… second, and then divide that by 86400 seconds in…
Post: Goal driven performance optimization
December 22, 2008 By Leave a Comment
…times – mysql, memcache, sphinx, web services etc. For web applications doing processing in a single thread the following simple formula applies wall_time…queries, cache them, tune them so they are faster (often at the same time…
Post: Faster MySQL failover with SELECT mirroring
February 1, 2009 By 9 Comments
… directions. Aside from MySQL Cluster, which is …queries. It just sits there replicating and doing nothing else. The problem is that the passive server’s caches… of the time taken to run the queries against the…second is the insert buffer. Notice the pages with no database or table name — the second…
Post: Are larger buffers always better ?
June 6, 2006 By 9 Comments
… better” so if “large” MySQL sample configuration is …with case which was running much faster with 32K sort_buffer_… was 9 seconds vs 8 minutes – 50 times. I … ENGINE=MyISAM DEFAULT CHARSET=utf8 select sql_no_cache count(*) from t1 where …cache may slow your opens and closes down, too large query_cache…
