Search Results for: index date function

When is MIN(DATE) != MIN(DATE) ?

Inspiration for this post is courtesy of a friend and former colleague of mine, Greg Youngblood, who pinged me last week with an interesting MySQL puzzle. He was running Percona Server 5.5.21 with a table structure that looks something like this:

When he ran this query:

The result came back as 2012-06-22 10:28:16. […]

MySQL Performance – eliminating ORDER BY function

One of the first rules you would learn about MySQL Performance Optimization is to avoid using functions when comparing constants or order by. Ie use indexed_col=N is good. function(indexed_col)=N is bad because MySQL Typically will be unable to use index on the column even if function is very simple such as arithmetic operation. Same can […]

Google Compute Engine adds Percona XtraDB Cluster to click-to-deploy process

I’m happy to announce that Google has added Click-to-deploy functionality for Percona XtraDB Cluster (PXC) on Google Cloud Compute nodes. This gives you the ability to rapidly spin up a cluster for experimentation, performance testing, or even production use on Google Compute Engine virtual machines. What is Percona XtraDB Cluster? Percona XtraDB Cluster is a […]

Avoiding MySQL ALTER table downtime

MySQL table alterations can interrupt production traffic causing bad customer experience or in worst cases, loss of revenue. Not all DBAs, developers, syadmins know MySQL well enough to avoid this pitfall. DBAs usually encounter these kinds of production interruptions when working with upgrade scripts that touch both application and database or if an inexperienced admin/dev […]

How to deal with MySQL deadlocks

A deadlock in MySQL happens when two or more transactions mutually hold and request for locks, creating a cycle of dependencies. In a transaction system, deadlocks are a fact of life and not completely avoidable. InnoDB automatically detects transaction deadlocks, rollbacks a transaction immediately and returns an error. It uses a metric to pick the […]

MySQL upgrade best practices

MySQL upgrades are necessary tasks and we field a variety of questions here at Percona Support regarding MySQL upgrade best practices. This post highlights recommended ways to upgrade MySQL in different scenarios. Why are MySQL upgrades needed? The reasons are many and include: Access to new features, performance benefits, bug fixes…. However, MySQL upgrades can […]

Using sysbench 0.5 for performing MySQL benchmarks

Given the recent excitement & interest around OpenStack I wanted to make sure I was ready to conduct appropriate evaluations of system performance.  I generally turn to sysbench since it comes with a variety of different tests (accessed via –test= option interface), including: fileio – File I/O test cpu – CPU performance test memory – […]

Galera replication – how to recover a PXC cluster

Galera replication for MySQL brings not only the new, great features to our ecosystem, but also introduces completely new maintenance techniques. Are you concerned about adding such new complexity to your MySQL environment? Perhaps that concern is unnecessarily. I am going to present here some simple tips that hopefully will let fresh Galera users prevent […]