May 21, 2013

Benchmarking Percona Server TokuDB vs InnoDB

May 7, 2013 By 29 Comments

After compiling Percona Server with TokuDB, of course I wanted to compare InnoDB performance vs TokuDB. I have a particular workload I’m interested in testing – it is an insert-intensive workload (which is TokuDB’s strong suit) with some roll-up aggregation, which should produce updates in-place (I will use INSERT .. ON DUPLICATE KEY UPDATE statements [...]

Filed Under: Benchmarks, MySQL, Percona Server Tagged With: , , ,

InnoDB Full-text Search in MySQL 5.6: Part 2, The Queries!

March 4, 2013 By 7 Comments

This is part 2 in a 3 part series. In part 1, we took a quick look at some initial configuration of InnoDB full-text search and discovered a little bit of quirky behavior; here, we are going to run some queries and compare the result sets. Our hope is that the one of two things [...]

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

MySQL optimizer: ANALYZE TABLE and Waiting for table flush

February 27, 2013 By 3 Comments

The MySQL optimizer makes the decision of what execution plan to use based on the information provided by the storage engines. That information is not accurate in some engines like InnoDB and they are based in statistics calculations therefore sometimes some tune is needed. In InnoDB these statistics are calculated automatically, check the following blog [...]

Filed Under: MySQL Tagged With: , , , ,

MySQL 5.5 and MySQL 5.6 default variable values differences

February 21, 2013 By 8 Comments

As the part of analyzing surprising MySQL 5.5 vs MySQL 5.6 performance results I’ve been looking at changes to default variable values. To do that I’ve loaded the values from MySQL 5.5.30 and MySQL 5.6.10 to the different tables and ran the query:

Lets go over to see what are the most important changes [...]

Filed Under: Insight for DBAs, MySQL Tagged With: , , ,

Innodb Table Locks

July 31, 2012 By 4 Comments

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 [...]

Filed Under: Insight for DBAs, MySQL

How FLUSH TABLES WITH READ LOCK works with Innodb Tables

March 23, 2012 By 20 Comments

Many backup tools including Percona Xtrabackup, MyLVMBackup and others use FLUSH TABLES WITH READ LOCK to temporary make MySQL read only. In many cases the period for which server has to be made read only is very short, just few seconds, yet the impact of FLUSH TABLES WITH READ LOCK can be quite large because [...]

Filed Under: Insight for DBAs, MySQL

Ultimate MySQL variable and status reference list

January 8, 2011 By 4 Comments

I am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just as frequently, I want to look up blog posts on variables, or look for content in the Percona documentation or forums. So I present to you what is now my newest Firefox toolbar bookmark: an option and [...]

Filed Under: Insight for DBAs, MySQL

How fast is FLUSH TABLES WITH READ LOCK?

April 24, 2010 By 30 Comments

A week or so ago at the MySQL conference, I visited one of the backup vendors in the Expo Hall. I started to chat with them about their MySQL backup product. One of the representatives told me that their backup product uses FLUSH TABLES WITH READ LOCK, which he admitted takes a global lock on [...]

Filed Under: Insight for Developers, MySQL Tagged With:

table_cache negative scalability

November 16, 2009 By 23 Comments

Couple of months ago there was a post by FreshBooks on getting great performance improvements by lowering table_cache variable. So I decided to investigate what is really happening here. The “common sense” approach to tuning caches is to get them as large as you can if you have enough resources (such as memory). With MySQL [...]

Filed Under: Benchmarks Tagged With:

Innodb performance gotcha w Larger queries.

August 28, 2009 By 7 Comments

Couple of days ago I was looking for a way to improve update performance for the application and I was replacing single value UPDATE with multiple value REPLACE (though I also saw the same problem with INSERT ON DUPLICATE KEY UPDATE) As I went from 1 value to 3 or 10 in the batch performance [...]

Filed Under: Insight for Developers Tagged With:
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