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More on MySQL transaction descriptors optimization

April 26, 2013 By Alexey Kopytov Leave a Comment

Since my first post on MySQL transaction descriptors optimization introduced in Percona Server 5.5.30-30.2 and a followup by Dimitri Kravchuk, we have received a large number of questions on why the benchmark results in both posts look rather different. We were curious as well, so we tried to answer that question by retrying benchmarks on [...]

Filed Under: Benchmarks, MySQL Tagged With: MySQL transaction descriptors, Optimization

MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark

March 11, 2013 By Justin Swanhart 7 Comments

So far most of the benchmarks posted about MySQL 5.6 use the sysbench OLTP workload. I wanted to test a set of queries which, unlike sysbench, utilize joins. I also wanted an easily reproducible set of data which is more rich than the simple sysbench table. The Star Schema Benchmark (SSB) seems ideal for this. [...]

Filed Under: MySQL Tagged With: InnoDB plugin, Justin Swanhart, MySQL 5.5, MySQL 5.6, Star Schema Benchmark (SSB), sysbench

Sphinx search performance optimization: multi-threaded search

January 16, 2013 By Aurimas Mikalauskas 8 Comments

Queries in MySQL, Sphinx and many other database or search engines are typically single-threaded. That is when you issue a single query on your brand new r910 with 32 CPU cores and 16 disks, the maximum that is going to be used to process this query at any given point is 1 CPU core and [...]

Filed Under: MySQL Tagged With: FullText Search, Performance, Sphinx, Tips

Edge-case behavior of INSERT…ODKU

October 27, 2012 By Ernie Souhrada 6 Comments

A few weeks back, I was working on a customer issue wherein they were observing database performance that dropped through the floor (to the point of an outage) roughly every 4 weeks or so. Nothing special about the environment, the hardware, or the queries; really, the majority of the database was a single table with [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL

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

September 4, 2012 By Ernie Souhrada 5 Comments

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:

CREATE TABLE foo (
 id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
 uid INT UNSIGNED NOT NULL,
 update_time DATETIME NOT NULL,
 ....
 INDEX `uid` (uid, update_time),
 INDEX `bar` (some_other_columns)
 ....
) ENGINE=InnoDB;

CREATE TABLE foo (

id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,

uid INT UNSIGNED NOT NULL,

update_time DATETIME NOT NULL,

....

INDEX `uid` (uid, update_time),

INDEX `bar` (some_other_columns)

....

) ENGINE=InnoDB;

When he ran this query:

SELECT MIN(update_time) FROM foo WHERE update_time IS NOT NULL AND update_time <> '0000-00-00 00:00:00';

1	SELECT MIN(update_time) FROM foo WHERE update_time IS NOT NULL AND update_time <> '0000-00-00 00:00:00';

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

Filed Under: Insight for DBAs, Insight for Developers, MySQL

Wow. My 6 year old MySQL Bug is finally fixed in MySQL 5.6

August 30, 2012 By Peter Zaitsev 2 Comments

I got the message in the morning today about the bug being fixed in MySQL 5.6.6…. which I reported in Early 2006 (while still being with MySQL) and running MySQL 4.1 I honestly thought this issue was fixed long ago as it was indeed pretty annoying. I must say I’m very impressed with Oracle team [...]

Filed Under: Insight for DBAs, MySQL

A case for MariaDB’s Hash Joins

May 31, 2012 By Ovais Tariq Leave a Comment

MariaDB 5.3/5.5 has introduced a new join type “Hash Joins” which is an implementation of a Classic Block-based Hash Join Algorithm. In this post we will see what the Hash Join is, how it works and for what types of queries would it be the right choice. I will show the results of executing benchmarks [...]

Filed Under: Benchmarks, Insight for DBAs, MySQL Tagged With: batched key access, block nested loop, hash join, JOIN Performance, MariaDB, Performance

Testing Fusion-io ioDrive

May 3, 2012 By Vadim Tkachenko 2 Comments

Following my series of posts on testing different SSD, in my last post I mentioned that SATA SSD performance is getting closer to PCIe cards. It really makes sense to test it under MySQL workload, but before getting to that, let me review the same workload on Fusion-io ioDrive PCIe card. This is yet previous [...]

Filed Under: Benchmarks, Hardware and Storage, MySQL

Join Optimizations in MySQL 5.6 and MariaDB 5.5

April 4, 2012 By Ovais Tariq 4 Comments

This is the third blog post in the series of blog posts leading up to the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. This blog post is targeted at the join related optimizations introduced in the optimizer. These optimizations are available in both MySQL 5.6 and MariaDB 5.5, and MariaDB 5.5 [...]

Filed Under: Benchmarks, Insight for DBAs, MySQL Tagged With: batched key access, BKA, hash join, io, JOIN Performance, join_buffer, MariaDB, mrr_buffer, multi range read, MySQL Performance, nested loop join, Optimizer, random read, read_rnd_buffer, sequential read

Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5

March 21, 2012 By Ovais Tariq 10 Comments

This is the second blog post in the series of blog posts leading up to the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. This blog post is aimed at the optimizer enhancement Multi Range Read (MRR). Its available in both MySQL 5.6 and MariaDB 5.5 Now let’s take a look at [...]

Filed Under: Benchmarks, Insight for DBAs, MySQL Tagged With: InnoDB, MariaDB, mrr_buffer, multi range read, MySQL, MySQL Index Scan, MySQL Indexes, Optimization, Optimizer, query, random read, range lookup, read_rnd_buffer, secondary key lookup, sequential read

More on MySQL transaction descriptors optimization

MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark

Sphinx search performance optimization: multi-threaded search

Edge-case behavior of INSERT…ODKU

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

Wow. My 6 year old MySQL Bug is finally fixed in MySQL 5.6

A case for MariaDB’s Hash Joins

Testing Fusion-io ioDrive

Join Optimizations in MySQL 5.6 and MariaDB 5.5

Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5

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