May 22, 2013

Unexpected problem with triggers and mysqldump

Some time ago, I had to convert all tables of a database from MyISAM to InnoDB on a new server. The plan was to take a logical dump on the master, exporting separately the schema and the data, then edit the CREATE TABLE statements to ensure all tables are created with InnoDB, and reload everything [...]

MySQL 5.6: Improvements in the Nutshell

Preparing for my talk for Percona MySQL University in Raleigh,NC, Tuesday 29th of January I have created the outline of improvements available in MySQL 5.6 which I thought was worth sharing to give a feel for how massive work have been done for this release in variety of areas. I’m sure the list is not [...]

Read/Write Splitting with PHP Webinar Questions Followup

Today I gave a presentation on “Read/Write Splitting with PHP” for Percona Webinars.  If you missed it, you can still register to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions.  I answered as many as I could during the session, but here are [...]

Sphinx search performance optimization: multi-threaded search

Queries in MySQL, Sphinx and many other database or search engines are typically single-threaded. That is when you issue a single query on your brand new r910 with 32 CPU cores and 16 disks, the maximum that is going to be used to process this query at any given point is 1 CPU core and [...]

Quickly finding unused indexes (and estimating their size)

I had a customer recently who needed to reduce their database size on disk quickly without a lot of messy schema redesign and application recoding.  They didn’t want to drop any actual data, and their index usage was fairly high, so we decided to look for unused indexes that could be removed. Collecting data It’s [...]

Announcing Percona XtraDB Cluster 5.5.28-23.7

Percona is glad to announce the release of Percona XtraDB Cluster on November 15th, 2012. Binaries are available from downloads area or from our software repositories. Features: Percona XtraDB Cluster has ported Twitter’s MySQL NUMA patch. This patch implements improved NUMA support as it prevents imbalanced memory allocation across NUMA nodes. Number of binlog files [...]

Minimizing Downtime from Lengthy AWS Outages

Well, it happened again…  Another lengthy EBS outage in the US-East region impacted several sites across the net.  While failures like this are rare, they can be quite costly and translate into headaches for the operations team when impact production systems for any length of time.  At Percona, we routinely help clients architect and deploy [...]

Testing Intel® SSD 910

Intel came on PCI-e SSD market with their Intel SSD 910 card. With a slogan “The ultimate data center SSD” I assume Intel targets rather a server grade hardware, not consumer level. I’ve got one of this card into our lab. I should say it is very price competitive, comparing with other enterprise level PCIe [...]

Innodb Table Locks

Innodb uses row level locks right ? So if you see locked tables reported in SHOW ENGINE INNODB STATUS you might be confused and rightfully so as Innodb table locking is a bit more complicated than traditional MyISAM table locks. Let me start with some examples. First lets run SELECT Query:

As you can [...]

SQL Injection Questions Followup

I presented a webinar today about SQL Injection, to try to clear up some of the misconceptions that many other blogs and articles have about this security risk.  You can register for the webinar even now that I’ve presented it, and you’ll be emailed a link to the recording, which will be available soon. During [...]