… to create or drop a table, or the database itself. Likewise, if a system administrator leaves a …to shut down MySQL so that it is killed forcibly (i.e. crashed) instead of gracefully shutting down for a…. It is surprising how often a server crashes, perhaps even cycling through crashes, and is not …
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
…a trivial way to crash MySQL to the user with basic privileges and asking me what to do. My answer to them is – there is nothing new to…tables in MySQL 5.1 Disk Space For MyISAM tables hosting providers used to use disk quotas for MyISAM tables…
Post: How to estimate time it takes Innodb to Recover ?
May 9, 2007 By 7 Comments
…size and workload. If you have tables with short rows your log …have small buffer pool you will have a lot of pages being flushed …MySQL 5.0 these seems to be done in the background. In the future to…to handle and crash Innodb few times to see how long it takes Innodb to recover. I’d recommend to crash…
Post: What to tune in MySQL Server after installation
September 29, 2006 By 116 Comments
… surprised how many people fail to provide any reasonable answer to this question, and how … you can tune quite a lot of variables in MySQL Servers only few …MySQL Server crashes. Value 2 only cause data loss with full OS crash. table_cache – Opening tables can be expensive. For example MyISAM tables…
Post: How much memory can MySQL use in the worst case?
February 12, 2009 By 17 Comments
…a crash: “It is possible that mysqld could use up to…a lot of tables. We’re trying to fix that, but it’s unbounded in a…mysql> set @a := repeat(‘a‘, 1024 * 1024 * 100); Query OK, 0 rows affected (2.34 sec) mysql> select get_lock(@a, 1); +—————–+ | get_lock(@a…
Post: Verifying backup integrity with CHECK TABLES
February 1, 2012 By 4 Comments
An attendee to Espen’s recent webinar asked how to check tables for corruption. This kind of ties into my recent post … best way to check for corruption is with CHECK TABLES, but if a page is corrupt, InnoDB will crash the server to prevent access to the… backup somewhere, start a server instance on it, and run CHECK TABLES. You can use the mysqlcheck program to do this conveniently. You…
Post: Upgrading MySQL
January 5, 2010 By 23 Comments
…a lot safer upgrade path than 4.1 to 5.1 just because so much more people have followed that road. So how…version and made it to caught up you can use mk-table-checksum to ensure data is …a bit so if something happens (like MySQL crashes) you have only one/few shard to deal with. P.S Happy New Year to…
Post: Two Types of MySQL Users
May 10, 2010 By 5 Comments
… they may even hack on MySQL. So this fraction of MySQL Community looks a lot larger than it is…MyISAM tables but they would not actually roll back ? Replication which can get broken by Server Crash ? A lot…a lot of flexibility how to build them. Honda Civic is boring but it gets you where you need to…
Post: Recovering Innodb table Corruption
July 4, 2008 By 19 Comments
…: file read of page 7. InnoDB: You may have to recover from a backup. 080703 23:46:16 InnoDB: Page dump in… want to CHECK your MyISAM table you use for recovery after MySQL crashes to make sure indexes are not corrupted. So we looked at how to get your data back from simple Innodb Table Corruption…
Post: How innodb_open_files affects performance
November 18, 2009 By 4 Comments
… besides MySQL table_cache Innodb maintains its own (called data dictionary) which keeps all tables ever accessed since table start – there is no variable to… of course can change a lot depending on hardware log file size workload and even when crash happen (how many unflushed changes we…
