April 24, 2014

Find unused indexes

I wrote one week ago about how to find duplicate indexes. This time we’ll learn how to find unused indexes to continue improving our schema and the overall performance. There are different possibilites and we’ll explore the two most common here. User Statistics from Percona Server and pt-index-usage. User Statistics User Statistics is an improvement […]

Percona Server 5.5.25-27.0 release delayed

Due to a bug in upstream MySQL ( http://bugs.mysql.com/bug.php?id=65745 ), we’ve decided to delay the release of the next Percona Server release until it is resolved. We had originally expected to release Percona Server 5.5.25-27.0 today and instead I’m informing you that we are not. Quoting Hartmut, who reported the bug: An UPDATE that should only modify […]

MySQL Upgrade Webinar Questions Followup

I did a Webinar about MySQL Upgrade – Best Practices Yesterday and there were some questions we could not answer during Webinar, following Jay’s Lead I decided to post them as a Blog Post. Q: Can you go directly MySQL 5.0 to 5.5 for MyISAM tables? MyISAM have not been getting any significant development since […]

ALTER TABLE: Creating Index by Sort and Buffer Pool Size

Today I was looking at the ALTER TABLE performance with fast index creation and without it with different buffer pool sizes. Results are pretty interesting. I used modified Sysbench table for these tests because original table as initially created only has index on column K which initially contains only zeros, which means index is very […]

Announcing Percona Live MySQL London

Looking for a great opportunity to share your MySQL knowledge with the MySQL community? Here is your chance. Percona is happy to announce that the dates of the Percona Live MySQL London Conference have been set for Dec. 3-4, 2012. Call for speakers is underway and will be open until August 17th, 2012. The conference […]

Announcing Percona XtraBackup 2.0.1

Percona is glad to announce the release of Percona XtraBackup 2.0.1 on June 25th, 2012. Downloads are available from our download site and Percona Software Repositories. This release is the current GA (Generally Available) stable release in the 2.0 series. This release contains over 20 fixed bugs, some of the more significant bugs fixed are: […]

Where Percona software goes before it’s released

Where does software go while it’s waiting for release? The answer is: our experimental repository! For anywhere from a few days to a week before we release them, we stage our software releases in the TESTING download area and in separate software repositories for Debian/Ubuntu and CentOS/RHEL. This is so that we can co-ordinate things such […]

DROP TABLE and stalls: Lazy Drop Table in Percona Server and the new fixes in MySQL

Suppose you have turned on innodb_file_per_table (which means that each table has its own tablespace), and you have to drop tables in a background every hour or every day. If its once every day then you can probably schedule the table dropping process to run during off-peak hours. But I have seen cases where the […]

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 […]

pt-online-schema-change and default values

When I’m doing conventional ALTER TABLE in MySQL I can ignore default value and it will be assigned based on the column type. For example this alter table sbtest add column v varchar(100) not null would work even though we do not specify default value. MySQL will assign empty string as default default value for […]