Innodb Locks, ActiveRecord and acts_as_ferret Problem
1 Dec2007

Last few days one of our customers (one of the largest Ruby on Rails sites on the Net) was struggling to solve some really strange problem – once upon a time they were getting an error from ActiveRecord on their site:

(ActiveRecord::StatementInvalid) "Mysql::Error: Lock wait timeout exceeded; try restarting transaction: UPDATE some_table.....

They have innodb_lock_wait_timeout set to 20 seconds. After a few hours of looking for strange transactions we were decided to create s script to dump SHOW INNODB STATUS and SHOW FULL PROCESSLIST commands output to a file every 10 seconds to catch one of those moments when this error occurred.

Today we’ve got next error and started digging in our logs…

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