Emergency

Search Results for: mysql print comment

Helgrinding MySQL with InnoDB for Synchronisation Errors, Fun and Profit

It is no secret that bugs related to multithreading–deadlocks, data races, starvations etc–have a big impact on application’s stability and are at the same time hard to find due to their nondeterministic nature.  Any tool …

Read More
 

How to Identify Bad Queries in MySQL

Finding bad queries is a big part of optimization. A scientific optimization process can be simplified to “can anything be improved for less than it costs not to improve it? – if not, we’re done.” …

Read More
 

Ultimate MySQL variable and status reference list

I am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just as frequently, I want to look up blog posts on variables, or look for content in the …

Read More
 

How to pretty-print my.cnf with a one-liner

When I’m looking at a server, I often want to see the /etc/my.cnf file nicely formatted, and with comments stripped. This Perl one-liner will pretty-print the file:

Read More
 

Apache PHP MySQL and Runaway Scripts

Sometimes due to programming error or due to very complex query you can get your PHP script running too long, well after user stopped waiting for the page to render and went browsing other sites. …

Read More
 

Debugging sleeping connections with MySQL

Have you ever seen connection in the SHOW PROCESSLIST output which is in “Sleep” state for a long time and you have no idea why this would happen ? I see if frequently with web …

Read More
 

Testing backup locks during Xtrabackup SST on Percona XtraDB Cluster

Background on Backup Locks I was very excited to see Backup locks support in release notes for the latest Percona XtraDB Cluster 5.6.21 release. For those who are not aware, backup locks offer an alternative to FLUSH …

Read More
 

Percona Server with TokuDB (beta): Installation, configuration

My previous post was an introduction to the TokuDB storage engine and aimed at explaining the basics of its design and how it differentiates from InnoDB/XtraDB. This post is all about motivating you to give it …

Read More
 

Why TokuDB does not use the ‘uint3korr’ function

The ‘uint3korr’ function inside of the mysqld server extracts a 3 byte unsigned integer from a memory buffer. One use is for ‘mediumint’ columns which encode their value in 3 bytes. MySQL 5.6 and MariaDB …

Read More
 

Percona XtraBackup – A workaround to the failed assertion bug

I recently conducted a test backup of my “master-slave” setup in my VirtualBox as I was migrating from Percona Server 5.6.12 to version 5.6.13-rel61.0 with Percona XtraBackup v2.2.0 rev. 4885. However, doing the backup on …

Read More