…a specific database, a set of databases, or specific tables; you can also configure the slave to replicate … it occurs. For example, if you see a large number of long-running queries in the output …quite like that in the MySQL world, except maybe MyISAM files on top of a clustered filesystem with …
Post: ZFS on Linux and MySQL
May 24, 2013 By 17 Comments
I am currently working with a large customer and I am involved with servers located in two … drops to 33% after the first snapshot so keeping a large number of snapshots running is simply not an option. With… work best with InnoDB, with MyISAM you’ll have to start the snapshot while holding a “flush tables with read lock” and…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
… fully sequential access, jam packed rows – quite possible scenario for MyISAM tables. Now if we take the same hard drive for fully…% or rows or less full table scan may be faster. Avoid joins to large tables Joining of large data sets using nested loops is very expensive. Try to avoid it. Joins to smaller tables is…
Post: Should you move from MyISAM to Innodb ?
January 12, 2009 By 59 Comments
…, background flushes while on the drawbacks side we see significantly large table size (especially if data size is close to memory size…) and when use other tables when it really gives substantial gains. I would not switch table to MyISAM because it gives 5% performance improvement but I can perfectly use MyISAM (or Archive) for logging…
Post: MySQL MyISAM Active Active Clustering - looking for trouble ?
March 15, 2007 By 4 Comments
… saying you can use MySQL with Active Active Clustering and MyISAM tables if you follow certain rules like enabling external locking, disabling… long time for large tables. Furthermore as I remember MySQL simply was not repairing corrupted tables in this configuration even if myisam_repair is… large you can’t afford multiple copies ? Well in this case you’re risking more in terms of downtime while repairing large tables…
Post: Efficient Boolean value storage for Innodb Tables
April 23, 2008 By 6 Comments
… this table – myisam_data_pointer_size is 6 default plus we need space for delete flag which makes 7 minimum row size MyISAM…% smaller. This is modest space savings of course but considering large per row overhead Innodb has this will transform to much… how things look for MyISAM for same tables: mysql> show table status like “%bool%” \G *************************** 1. row *************************** Name: bbool Engine: MyISAM Version: 10 Row…
Post: Slow DROP TABLE
June 16, 2009 By 21 Comments
… table files are deleted: | 3 | root | localhost | test | Query | 7 | rename result table | ALTER TABLE large_table ENGINE=MyISAM | | 679 | root | localhost | test | Query | 6 | Opening tables | select * from other_table limit 1 | The only…
Post: More on table_cache
November 26, 2009 By 7 Comments
… – note this is basically best case scenario for opening tables as MyISAM table headers which are being modified were fully cached in this…) table cache misses it is best to size table_cache large enough – even in the best case scenario for misses hit from large table_cache is faster. There are also possible optimization for “hit” path with large table cache though this should…
Post: table_cache negative scalability
November 16, 2009 By 23 Comments
… read-only benchmark. Why ? Because for MyISAM tables table header has to be modified each time the table is opened. In this case the… (opened_tables) to 10/sec or less by using large table_cache you should do so. However if you have so many tables you… Performance focused MySQL 5.4. As we can see large table_cache (or table_open_cache_ values indeed can cause significant performance problems…
Post: Finding out largest tables on MySQL Server
February 4, 2008 By 27 Comments
… the data which is mainly for informational purposes but for MyISAM can also help you to size your key buffer compared… also use it to see which tables may be worth to review in terms of indexes. Large index size compared to data… have a lot of large tables. On this instance it took 2.5 minutes to run for 450 tables. UPDATE: To make things…
