…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: How much overhead is caused by on disk temporary tables
August 16, 2007 By 26 Comments
… IO. Clearly OS write caching is not effective for relatively large area (which still fits in memory) which is getting a… linear dependence of table size, and it can get 100 times faster than MyISAM on disk table even in case temporary table is small… Performance of Disk MyISAM tables may not scale proportionally with table size, even when all data fits in memory MEMORY temporary tables can be…
Post: Using MyISAM in production
June 17, 2006 By 36 Comments
… view on using MyISAM in production. For me it is not only about table locks. Table locks is only one of MyISAM limitations you… to check recover our tables. If this happened make sure you have decent myisam_sort_buffer_size and large myisam_max_sort_file_size… many tables which are being repaired, each may allocate myisam_sort_buffer_size and MySQL could crash or go swapping. Second – table will…
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: 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: Enum Fields VS Varchar VS Int + Joined table: What is Faster?
January 24, 2008 By 30 Comments
… NULL, PRIMARY KEY (id), KEY state (state) ) ENGINE=MyISAM; 2) Table with VARCHAR: CREATE TABLE cities_varchar ( id int(10) unsigned NOT NULL… NULL, PRIMARY KEY (id), KEY state (state) ) ENGINE=MyISAM; 3) Table with INT: CREATE TABLE cities_join ( id int(10) unsigned NOT NULL… we can see that performance hit may not be as large as you expect. Though again a lot depends on your…
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…
