…size mrr_buffer_size. Both buffer sizes default to 256K in MySQL 5.6 and MariaDB 5.5 respectively, which might be low depending on…query times remain under a minute. So when the correct query execution plan is not used, there is no difference in query times between MySQL…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
…depending on system and table structure. Now if you data fully on…query runs as single thread (with exeption of MySQL Cluster) and MySQL issues IO requests one by one for query execution, which means if single query execution time…
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 22 Comments
…MySQL command line client was used to execute the a script file containing the 11 queries…ON (t.Year=t2.Year); The performance of the following queries depends on the size…
Post: How much overhead is caused by on disk temporary tables
August 16, 2007 By 26 Comments
…does not affect current session. A little gotcha which still catches me. For 1M rows we have mysql> set max_heap_table_size=1000000000; Query… table scales pretty well with query execution time being close to linear dependence of table size, and it can get 100 times faster than MyISAM on disk table …
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
…executed prepared statement. Innodb Table Cache Leak – Innodb never shrinks its internal table…query is internally presented using parse tree inside MySQL which of course depends on query size which is controlled by max_allowed_packet. However some MySQL…
Post: Innodb undo segment size and transaction isolation
January 12, 2011 By 2 Comments
…will prevent other transactions for execution, this however only applies …OS thread id 1630148928 MySQL thread id 188790, query id 14796224615 host.domain…space, depending on row size. Long blobs (the ones which are not stored on …table at that point in time. If you use READ-COMMITTED mode Innodb does…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…queries, in total execution time. By the way, the slow query logs in the stock MySQL…
Post: MySQL Server Variables - SQL layer or Storage Engine specific.
June 8, 2006 By 14 Comments
…size implicit temporary table (created during query execution automatically) will grow as MEMORY table before it will be converted to on disk MyISAM table. It does not limit size…
Post: Enum Fields VS Varchar VS Int + Joined table: What is Faster?
January 24, 2008 By 27 Comments
…size significantly. In many cases size difference will be significantly less. All tests are runned 1000 times and the result time…query executed basically on single table querying…MySQL to store Join result in temporary table…depends on your data and queries…
Post: MySQL caching methods and tips
April 4, 2011 By 4 Comments
…table, the query cache entries for every query which accessed that table must be invalidated. If a frequently executed or expensive query is invalidated, response time…time approaches the expiration time. This does not…the MySQL query cache are limited in size…. performance is dependent on your cache,…
