November 22, 2014

Innodb Table Locks

Innodb uses row level locks right ? So if you see locked tables reported in SHOW ENGINE INNODB STATUS you might be confused and rightfully so as Innodb table locking is a bit more complicated than traditional MyISAM table locks. Let me start with some examples. First lets run SELECT Query:

As you can […]

Shard-Query adds parallelism to queries

Preamble: On performance, workload and scalability: MySQL has always been focused on OLTP workloads. In fact, both Percona Server and MySQL 5.5.7rc have numerous performance improvements which benefit workloads that have high concurrency. Typical OLTP workloads feature numerous clients (perhaps hundreds or thousands) each reading and writing small chunks of data. The recent improvements to […]

What exactly is read_rnd_buffer_size

Looking for documentation for read_rnd_buffer_size you would find descriptions such as “The read_rnd_buffer_size is used after a sort, when reading rows in sorted order. If you use many queries with ORDER BY, upping this can improve performance” which is cool but it does not really tell you how exactly read_rnd_buffer_size works as well as which […]

PHP Large result sets and summary tables.

We’re working with web site preparing for massive growth. To make sure it handles large data sets as part of the process we work on generation test database of significant size as testing your application on table with 1000 rows may well give you very dangerous false sense of security. One of the process web […]

SHOW INNODB STATUS walk through

Many people asked me to publish a walk through SHOW INNODB STATUS output, showing what you can learn from SHOW INNODB STATUS output and how to use this info to improve MySQL Performance. To start with basics SHOW INNODB STATUS is command which prints out a lot of internal Innodb performance counters, statistics, information about […]

INSERT INTO … SELECT Performance with Innodb tables.

Everyone using Innodb tables probably got use to the fact Innodb tables perform non locking reads, meaning unless you use some modifiers such as LOCK IN SHARE MODE or FOR UPDATE, SELECT statements will not lock any rows while running. This is generally correct, however there a notable exception – INSERT INTO table1 SELECT * […]

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 a try and have a look for yourself. Percona Server is not officially supporting TokuDB as of today, though the […]

Announcing Percona Server for MySQL version 5.5.29-30.0

Percona is glad to announce the release of Percona Server for MySQL version 5.5.29-30.0 on February 26th, 2013 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.5.29, including all the bug fixes in it, Percona Server 5.5.29-30.0 is now the current stable release in the 5.5 series. All of Percona‘s software is open-source and free, all the details […]

Four ways to optimize paginated displays

A paginated display is one of the top optimization scenarios we see in the real world. Search results pages, leaderboards, and most-popular lists are good examples. You know the design pattern: display 20 results in some most-relevant order. Show a “next” and “previous” link. And usually, show how many items are in the whole list […]

Fighting MySQL Replication Lag

The problem of MySQL Replication unable to catch up is quite common in MySQL world and in fact I already wrote about it. There are many aspects of managing mysql replication lag such as using proper hardware and configuring it properly. In this post I will just look at couple of query design mistakes which […]