April 19, 2014

10 MySQL settings to tune after installation

When we are hired for a MySQL performance audit, we are expected to review the MySQL configuration and to suggest improvements. Many people are surprised because in most cases, we only suggest to change a few settings even though hundreds of options are available. The goal of this post is to give you a list […]

Heartbleed: Separating FAQ From FUD

If you’ve been following this blog (my colleague, David Busby, posted about it yesterday) or any tech news outlet in the past few days, you’ve probably seen some mention of the “Heartbleed” vulnerability in certain versions of the OpenSSL library. So what is ‘Heartbleed’, really? In short, Heartbleed is an information-leak issue. An attacker can […]

Percona XtraDB Cluster – installation and setup webinar follow up Q&A

Thanks for all, who attended my webinar, I got many questions and I wanted to take this opportunity to answer them. Q: Even ntp has a delay of 0.3-0.4 between servers does that mean a 0.25 as from logs can be an issue ? A: My demo vms were running for a few hours before […]

Flexviews – part 3 – improving query performance using materialized views

Combating “data drift” In my first post in this series, I described materialized views (MVs). An MV is essentially a cached result set at one point in time. The contents of the MV will become incorrect (out of sync) when the underlying data changes. This loss of synchronization is sometimes called drift. This is conceptually […]

Recovering Innodb table Corruption

Assume you’re running MySQL with Innodb tables and you’ve got crappy hardware, driver bug, kernel bug, unlucky power failure or some rare MySQL bug and some pages in Innodb tablespace got corrupted. In such cases Innodb will typically print something like this: InnoDB: Database page corruption on disk or a failed InnoDB: file read of […]

Estimating Undo Space needed for LVM Snapshot

We know MySQL Backups using LVM are pretty cool (check out mylvmbackup) or MMM though it is quite typical LVM is not configurable properly to be usable for MySQL Backups. Quite frequently I find LVM installed on the system but no free space left to be used as snapshot undo space, which means LVM is […]