April 23, 2014

How to reclaim space in InnoDB when innodb_file_per_table is ON

When innodb_file_per_table is OFF and all data is going to be stored in ibdata files. If you drop some tables of delete some data then there is no any other way to reclaim that unused disk space except dump/reload method. When Innodb_file_per_table is ON, each table stores data and indexes in it’s own tablespace file. […]

Percona Server 5.5.30-30.2 rerelease fixes non-restart issue

In our last 5.5 series release of Percona Server, we included a regression in the RPM packaging that prevented the server from restarting following an upgrade — instead, the server would remain stopped after the upgrade was completed regardless of its state before updating. This caused some problems for some users, especially if automatic upgrading was configured […]

On Character Sets and Disappearing Tables

The MySQL manual tells us that regardless of whether or not we use “SET FOREIGN_KEY_CHECKS=0″ before making schema changes, InnoDB will not allow a column referenced by a foreign key constraint to be modified in such a way that the foreign key will reference a column with a mismatched data type. For instance, if we […]

Beware the Innodb Table Monitor

As I stated in my last post, I decided to use the Innodb Table monitor to diagnose an Index count mismatch error a customers found in their mysqld.err log to verify if the problem still existed. The Innodb Table Monitor has existed for basically forever in Innodb (the MySQL manual discusses it back in the 4.1 […]

Converting Character Sets

The web is going the way of utf8. Drizzle has chosen it as the default character set, most back-ends to websites use it to store text data, and those who are still using latin1 have begun to migrate their databases to utf8. Googling for “mysql convert charset to utf8″ results in a plethora of sites, […]

Heikki Tuuri Innodb answers – Part I

Its almost a month since I promised Heikki Tuuri to answer Innodb Questions. Heikki is a busy man so I got answers to only some of the questions but as people still poking me about this I decided to publish the answers I have so far. Plus we may get some interesting follow up questions […]

InnoDB vs MyISAM vs Falcon benchmarks – part 1

Several days ago MySQL AB made new storage engine Falcon available for wide auditory. We cannot miss this event and executed several benchmarks to see how Falcon performs in comparison to InnoDB and MyISAM. The second goal of benchmark was a popular myth that MyISAM is faster than InnoDB in reads, as InnoDB is transactional, […]