If you’re running an operation on a large number of rows within a table that uses the InnoDB storage engine, you might see this error: ERROR 1206 (HY000): The total number of locks exceeds the lock table size MySQL is trying to tell you that it doesn’t have enough room to store all of the row locks that it would need to execute your query. The only way to fix it for sure is to adjust innodb_buffer_pool_size and restart MySQL.
This problem has cropped up for me a few times, but I’ve always forgotten to make a post about it. If you’re working with a large InnoDB table and you’re updating, inserting, or deleting a large volume of rows, you may stumble upon this error: InnoDB stores its lock tables in the main buffer pool. This means that the number of locks you can have at the same time is limited by the innodb_buffer_pool_size variable that was set when MySQL was started.
When I tried to do an automatic upgrade from WordPress 2.7.1 to 2.8 yesterday, it failed miserably. The files were all put in place, but when I tried to load /wp-admin/upgrade.php, this error popped up: I was perplexed at the error, so I restored from a backup and began upgrading manually. The manual upgrades have always worked well for me in the past, so I figured this would probably fix the problem.
Users of PHPMyAdmin 3.x may find that the table indexes are automatically hidden at the bottom of the page. I find this to be a huge annoyance since table indexes are tremendously important to the structure of the table. If you don’t want to downgrade to PHPMyAdmin 2.x, just add the following line to the top of your config.inc.php file: This will cause the indexes to be displayed when you click Structure for a certain table.
Some of you may be wondering “why would you want to use Rails without a database?” There are several situations why a database would not be needed, and I’ve run into quite a few of them. One of the specific cases was when I wanted to write a web interface for an application that only had a REST interface available to the public. If you find yourself needing to write a Rails application without a database, just do the following: