…MySQL…myisam_recoverblogpercona.commanual myisam_recover_optionsblogpercona.commanual myisam_recover_optionsblogpercona.commanual myisam_repair_threadsblogpercona.commanual myisam_sort_buffer_sizeblogpercona.commanual myisam_stats_methodblogpercona.commanual myisam…
Post: Using CHAR keys for joins, how much is the overhead ?
June 18, 2007 By 18 Comments
… int(10) unsigned NOT NULL, KEY `i` (`i`), KEY `j` (`j`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 mysql> select sum(t1.i… I decided to check if using longer strings slows down things significantly and so I replaced …same ways but gave me much longer keys. The performance dropped down to 6.1 seconds which …
Post: MySQL 5.5 and MySQL 5.6 default variable values differences
February 21, 2013 By 8 Comments
…| 8 | | QUERY_CACHE_SIZE | 0 | 1048576 | | SLOW_QUERY_LOG_FILE | /mnt/data…MyISAM because Innodb was disabled for some reason was very error prone gotcha. Note this is as far as MySQL…if you do many create/drop of innodb tables. optimizer_…block_nested_loop=on,batched_key_access=off,materialization=on,…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…dropped packets). Starting to look at MySQL Assuming I don’t see anything noteworthy here, I’ll move on to the MySQL…’s time to convert MyISAM tables to InnoDB. (But then…users in the mysql.* tables, running mk-duplicate-key-checker to find…mysqlsla perl mysqlsla -lt slow /path/to/slow.log By default, …
Post: MySQL Server Memory Usage
May 17, 2006 By 21 Comments
…queries or make operation to swap seriously slowing down. On now legacy 32bit …queries. There can be mutiple key caches. Multiple key caches can be created …be able to run MySQL server out of memory MyISAM buffers. MyISAM may allocate buffer…quite sure I’ve missed something (drop me a note if you have…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
…drop in performance. This especially apples to index lookus and joins which we cover later. As everything usually slows…rows – quite possible scenario for MyISAM tables. Now if we …. There are also clustered keys in Innodb which combine index… slow. One of the reasons elevating this problem in MySQL …
Post: Working with large data sets in MySQL
July 5, 2007 By 12 Comments
… with large data things in MySQL is patience and careful planning. …slow down some queries considerably. You need to be planning for your handling of crashed MyISAM…MyISAM which builds “normal” indexes by sort builds primary key and unique indexes using keycache) If it does not performance may drop…
Comment: MySQL Server Memory Usage
September 1, 2006 By 21 Comments
…’Com_drop_db’, ’0′ ‘Com_drop_function’, ’0′ ‘Com_drop_index’, ’0′ ‘Com_drop_table’, ’0′ ‘Com_drop_…mysql/slow-queries.log max_connections=650 open_files_limit=6144 max_connect_errors=10000 interactive_timeout=3600 wait_timeout=3600 key_buffer_size=32M # Only for MyISAM which isnt…
Post: Innodb Recovery Update - The tricks what failed.
May 24, 2007 By 3 Comments
… should have been easy – dropping the table with corrupted … things: Versions later than MySQL 5.0.33 are … corrupted more seldom than MyISAM. Thanks to checksums and …Primary keys are typically simple integer keys in Innodb while secondary keys may…reload process can be so slow restoring even week old …
Comment: Should you move from MyISAM to Innodb ?
January 21, 2009 By 59 Comments
…is compressed (key-buffer-size=4). Total db content is only 15G. Our Inserts drop to …be the highest buffer allowed. if exeeded, mysql does not recognise the search engine (!) …slow too if we have partitions (indep. from compression). Without partitions, the innodb plugin was o.k., slower than MYISAM…
