April 18, 2014

Percona XtraDB Cluster 5.5.33-23.7.6 is now available

Percona is glad to announce the release of Percona XtraDB Cluster 5.5.33-23.7.6 on September 18, 2013. Binaries are available from the downloads area or from our software repositories. New Features: Default State Snapshot Transfer method, defined in wsrep_sst_method variable has been changed from mysqldump to rsync. New wsrep_reject_queries variable has been implemented that can be […]

Getting Percona PAM to work with Percona Server & its client apps

Percona Server is bundled with the PAM plugin which opens a plethora of ways to authenticate to MySQL such as restricting time when users can connect to MySQL, authenticate via a USB key, authenticate to an external authentication system such as LDAP and many, many more PAM compatible mechanisms. If you want to use PAM […]

Can’t Create Thread: Errno 11 (A Tale of Two Ulimits)

Recently some of my fellow Perconians and I have noticed a bit of an uptick in customer cases featuring the following error message:

The canonical solution to this issue, if you do a bit of Googling, is to increase the number of processes / threads available to the MySQL user, typically by adding a […]

Get Me Some Query Logs!

One of my favorite tools in the Percona Toolkit is pt-query-digest.  This tool is indispensable for identifying your top SQL queries, and analyzing which queries are accounting for your database load. But the report you get from pt-query-digest is only as good as the log of queries you give it as input.  You need a large […]

Write contentions on the query cache

While doing a performance audit for a customer a few weeks ago, I tried to improve the response time of their top slow query according to pt-query-digest‘s report. This query was run very frequently and had very unstable performance: during the time data was collected, response time varied from 50µs to 1s. When I ran […]

Secure passwords being insecure

If you follow the general advices to create secure password the following ones seem to be secure, right? s11P$||!sh&2 pr0&!!ke0 3kj39|!381 The answer to the question is, “it depends on how you use them” Notice that these passwords all contain multiple exclamation points and ampersands which are normally special characters for your shell. The people […]

Fishing with dynamite, brought to you by the randgen and dbqp

I tend to speak highly of the random query generator as a testing tool and thought I would share a story that shows how it can really shine. At our recent dev team meeting, we spent approximately 30 minutes of hack time to produce test cases for 3 rather hard to duplicate bugs. Of course, […]

Shard-Query EC2 images available

Infobright and InnoDB AMI images are now available There are now demonstration AMI images for Shard-Query. Each image comes pre-loaded with the data used in the previous Shard-Query blog post. The data in the each image is split into 20 “shards”. This blog post will refer to an EC2 instances as a node from here […]

Shard-Query turbo charges Infobright community edition (ICE)

Shard-Query is an open source tool kit which helps improve the performance of queries against a MySQL database by distributing the work over multiple machines and/or multiple cores. This is similar to the divide and conquer approach that Hive takes in combination with Hadoop. Shard-Query applies a clever approach to parallelism which allows it to […]

EXPLAIN EXTENDED can tell you all kinds of interesting things

While many people are familiar with the MySQL EXPLAIN command, fewer people are familiar with “extended explain” which was added in MySQL 4.1 EXPLAIN EXTENDED can show you what the MySQL optimizer does to your query. You might not know this, but MySQL can dramatically change your query before it actually executes it. This process […]