July 25, 2014

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 […]

Best kept MySQLDump Secret

Many people use mysqldump –single-transaction to get consistent backup for their Innodb tables without making database read only. In most cases it works, but did you know there are some cases when you can get table entirely missing from the backup if you use this technique ? The problem comes from the fact how MySQL’s […]

Side load may massively impact your MySQL Performance

When we’re looking at benchmarks we typically run some stable workload and we run it in isolation – nothing else is happening on the system. This is not however how things happen in real world when we have significant variance in the load and many things can be happening concurrently. It is very typical to […]

Percona Server 5.5.11-20.2 Stable Release

Percona Server 5.5.11-20.2 is now available for download, including an experimental build for MacOS. Released on April 28, 2011, it is the current stable release in the the 5.5 series. New Features HandlerSocket, a NoSQL plugin for MySQL, has been updated to the latest stable version as April 11th, 2011. InnoDB fast index creation now […]

Replication of MEMORY (HEAP) Tables

Some Applications need to store some transient data which is frequently regenerated and MEMORY table look like a very good match for this sort of tasks. Unfortunately this will bite when you will be looking to add Replication to your environment as MEMORY tables do not play well with replication.

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 […]

Predicting how long data load would take

I had this question asked many times during last week, and there is really no easy answer. There are just way too many variables to consider especially while loading large schemas with a lot of different table structures. So which variables affect the load speed: Table Structure This one is tricky. The shorter rows you […]

Wishes for mysqldump

Dealing with dumping and recovery of large and partially corrupted database I’ve got couple of feature ideas for mysqldump or similar tool and appropriate import tool Dump in parallel single thread dump is not efficient of course especially on systems with multiple CPUs and disks. It is lesser issue in recovery case because import takes […]

Introducing backup locks in Percona Server

TL;DR version: The backup locks feature introduced in Percona Server 5.6.16-64.0 is a lightweight alternative to FLUSH TABLES WITH READ LOCK and can be used to take both physical and logical backups with less downtime on busy servers. To employ the feature with mysqldump, use mysqldump –lock-for-backup –single-transaction. The next release of Percona XtraBackup will […]

New mydumper 0.6.1 release offers performance and usability features

One of the tasks within Percona Remote DBA is to ensure we have reliable backups with minimal impact. To accomplish this, one of the tools our team uses is called mydumper. We use mydumper for logical backups because of several nice features. Some of them are: multithreaded, producing very fast backups compared to mysqldump almost […]