…it helped:-). At the moment the server has around 21 GB of memory used for applications (of which Mysql is the main one…to automate it a bit. I also like to keep tables small enough, “sharding” to many tables before they become so large it would take days to do…
Post: Shard-Query adds parallelism to queries
November 15, 2010 By 18 Comments
…queries (or only one) to demonstrate how much improvement could be made to MySQL so that is could better utilize all available resources (that is…one big chunk of data in one query, it runs many smaller queries each requesting significantly less data. On the other hand, MySQL 5.5.7 does not do…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 28 Comments
…smaller ones. If you make some assumptions that are very hard to prove, there actually is…or two and it appears to work — so we turn into little Pavlovian DBAs and try to do that every time. It…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…to build for massive scalability, how to do read-write splitting without breaking the user experience, how to take online non-blocking backups, or…MySQL server’s limitation of one-second granularity makes it hide problem queries that are faster than one second (which in a high-performance system is…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
…MySQL is lack of advanced join methods at this point (the work is on a way) – MySQL can’t do hash join or sort merge join – it…MySQL Cluster) and MySQL issues IO requests one by one for query execution, which means if single query execution time is your concern many…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…to my surprise MySQL 5.6.10 did not get much faster during the repeat runs, compared to…queries to find an anomaly. I am going to focus on the first query, which uses only one join. Since it is practical for a query with only one…
Post: How to load large files safely into InnoDB with LOAD DATA INFILE
July 3, 2008 By 29 Comments
…it creates one big transaction with a lot of undo log entries. This has a lot of costs. To name a few: the big…it would be faster to just shut everything down and re-clone the machine from another, which takes about 10 or 12 hours. InnoDB is…
Post: How to calculate a good InnoDB log file size
November 21, 2008 By 38 Comments
…it or not. Run these queries at your server’s peak usage time: mysql> pager grep sequence PAGER set to ‘grep sequence’ mysql…faster than you might expect with a big…is just wrong. One final note: huge buffer pools or really unusual workloads may require bigger (or smaller!) log sizes. This is…
Post: Working with large data sets in MySQL
July 5, 2007 By 12 Comments
…to do careful process of ALTERing table on the slave and switching roles or some other techniques. You can’t run many simple reporting queries…it does not performance may drop performance order of magnitude. This is actually one of the reasons I try to keep data in smaller…
Post: New SpecJAppServer results at MySQL and Sun.
November 12, 2008 By Leave a Comment
…it mean the J2EE system got saturated before the database ? Or does it mean MySQL did not scale well to…do small sorts it is indeed better to have smaller sort buffer because allocating it will likely be faster. query_cache_size = 0M – query cache disabled. Not a big…
