Planet MySQL Planet MySQL: Meta Deutsch Español Français Italiano 日本語 Русский Português 中文
Showing entries 1 to 2

Displaying posts with tag: problem (reset)

MySQL Indexing Considerations Of Implementing A Priority Field In Your Application
+0 Vote Up -0Vote Down

Introduction

If you, like me, are building or thinking of implementing a MySQL-powered application that has any need for prioritizing selecting certain data over other data, this article is for you.

Example

As a real world example, consider a queue-like video processing system. Your application receives new videos and processes them. The volume of incoming videos can at times be higher than the processing rate because the process is CPU bound, so occasionally a pretty long queue may form. You will try to process them as fast as you can but…

Note that I am using a queue here, so the the next item to be processed is a result of sorting by some sort of field in a ascending order, for example ORDER BY id or ORDER BY upload_date. I’ll pick the id sort here.

  [Read more...]
Innodb Locks, ActiveRecord and acts_as_ferret Problem
+0 Vote Up -0Vote Down

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:

1
(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…

After a couple of hours of looking in logs, parsing binary logs from MySQL


  [Read more...]
Showing entries 1 to 2

Planet MySQL © 1995, 2014, Oracle Corporation and/or its affiliates   Legal Policies | Your Privacy Rights | Terms of Use

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.