September 17, 2014

InnoDB scalability issues due to tables without primary keys

Each day there is probably work done to improve performance of the InnoDB storage engine and remove bottlenecks and scalability issues. Hence there was another one I wanted to highlight: Scalability issues due to tables without primary keys This scalability issue is caused by the usage of tables without primary keys. This issue typically shows […]

MySQL Optimizer and Innodb Primary Key

Innodb primary key is special in many senses and I was always wondering how well MySQL is integrated with Innodb to take advantage of these special features. Lets see which things work and which things do not:

Long PRIMARY KEY for Innodb tables

I’ve written and spoke a lot about using short PRIMARY KEYs with Innodb tables due to the fact all other key will refer to the rows by primary key. I also recommended to use sequential primary keys so you do not end up having random primary key BTREE updates which can be very expensive. Today […]

When (and how) to move an InnoDB table outside the shared tablespace

In my last post, “A closer look at the MySQL ibdata1 disk space issue and big tables,” I looked at the growing ibdata1 problem under the perspective of having big tables residing inside the so-called shared tablespace. In the particular case that motivated that post, we had a customer running out of disk space in his […]

Percona XtraDB Cluster 5.6.19-25.6 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on July 21st 2014. Binaries are available from downloads area or from our software repositories. We’re also happy to announce that Ubuntu 14.04 LTS users can now download, install, and upgrade Percona XtraDB Cluster 5.6 from Percona’s software repositories. Based on Percona […]

Percona XtraDB Cluster 5.5.37-25.10 is now available

Percona is glad to announce the release of Percona XtraDB Cluster 5.5.37-25.10 on May 8, 2014. Binaries are available from the downloads area or from our software repositories. Based on Percona Server 5.5.37-35.0 including all the bug fixes in it, Galera Replicator 2.10 (including fixes in 2.9 and 2.10 milestones) and on wsrep API 25.10 […]

Notes from the Newb

Notes from the Newb. I’m relatively new to MySQL having come from the world of embedded micro-databases, and though I’m pretty familiar with a number of database systems, I’ve discovered that I have a lot to learn about MySQL. As a new member to the Percona team, I thought I’d have an ongoing blog theme […]

Percona XtraDB Cluster 5.6.15-25.5 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on March 20th 2014. Binaries are available from downloads area or from our software repositories. Based on Percona Server 5.6.15-63.0 including all the bug fixes in it, Galera Replicator 3.4 and on Codership wsrep API 25.5 is now the current General Availability […]

One more InnoDB gap lock to avoid

While troubleshooting deadlocks for a customer, I came around an interesting situation involving InnoDB gap locks. For a non-INSERT write operation where the WHERE clause does not match any row, I expected there should’ve been no locks to be held by the transaction, but I was wrong. Let’s take a look at this table and […]

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. […]