One problem made me puzzled for couple hours, but it was really interesting to figure out what's going on.

So let me introduce problem at first. The table is

PLAIN TEXT CODE:

1. CREATE TABLE `c` (
2.   `tracker_id` int(10) unsigned NOT NULL,
3.   `username` char(20) character set latin1 collate latin1_bin NOT NULL,
4.   `time_id` date NOT NULL,
5.   `block_id` int(10) unsigned default NULL,
6.   PRIMARY KEY  (`tracker_id`,`username`,`time_id`),
7.   KEY `block_id` (`block_id`)
8. ) ENGINE=InnoDB

Table has 11864696 rows and takes Data_length: 698,351,616 bytes on disk

The problem is that after restoring table from mysqldump, the query that scans data by primary key was slow. How slow ? Let me show.

The query in …

Someone recently posted this to an email list as a sample of an interesting SHOW INNODB STATUS output:

mysql> SHOW ENGINE INNODB STATUS\G
          _______  _______
|\     /|(  ____ \(  ____ \
| )   ( || (    \/| (    \/
| |   | || (_____ | (__
| |   | |(_____  )|  __)
| |   | |      ) || (
| (___) |/\____) || (____/\
(_______)\_______)(_______/

 _______  _______  _______ _________ _______  _______  _______  _______
(  ____ )(  ___  )(  ____ \\__   __/(  ____ \(  ____ )(  ____ \(  ____ \
| (    )|| (   ) || (    \/   ) (   | (    \/| (    )|| (    \/| (    \/
| (____)|| |   | || (_____    | |   | |      | (____)|| (__    | (_____
|  _____)| |   | |(_____  )   | |   | | ____ |     __)|  __)   (_____  )
| (      | |   | |      ) |   | |   | | \_  )| (\ (   | (            ) |
| )      | (___) |/\____) |   | |   | (___) || ) \ \__| (____/\/\____) |
|/       (_______)\_______)   )_(   (_______)|/   \__/(_______/\_______) 

I thought it was worth …

A recent photo from Highload.ru

I said in my last post, that we're interested in speaking at MySQL meetups, and I'm happy to say that the Los Angeles MySQL Meetup has taken us up on the offer.

On November 18th, I'll be giving an introductory talk on InnoDB/XtraDB Performance Optimization.  I will be the second speaker, with Carl Gelbart first speaking on Infobright.

What brings me to LA?  On the same day (18th Nov) I'll be teaching a one day class on Performance Optimization for MySQL with InnoDB and XtraDB.  If you haven't signed up yet - spaces are still available.

Entry posted by Morgan Tocker | …

First time I heard about Galera on Percona Performance Conference 2009, Seppo Jaakola was presenting "Galera: Multi-Master Synchronous MySQL Replication Clusters". It was impressed as I personally always wanted it for InnoDB, but we had it in plans at the bottom of the list, as this is very hard to implement properly.
The idea by itself is not new, I remember synchronous replication was announced for SolidDB on MySQL UC 2007, but later the product was killed by IBM.

So long time after PPC 2009 there was available version mysql-galera-0.6, which had serious flow, to setup a new node you had to take down whole cluster. And all this time Codership ( company that develops Galera) was working on 0.7 release that introduces node propagation keeping cluster online. You can play with 0.7pre release by yourself …

I’ve released version 1.1.4 of my improved Cacti templates. Unlike the prior release, which was solely bug fixes, this one includes new graphs in the MySQL template. Some of the graphs are of data that’s exposed in standard MySQL versions, but some of it is available only in Percona’s high-performance builds of the MySQL database server. If you don’t have a Percona build, those graphs will just contain nothing, but there is no detrimental effect.

This template release is fully backwards compatible with the previous release. The upgrade process is to copy the new PHP file into place and import the new template file. You can then add the new graphs to your hosts.

I’ve also taken the opportunity to address many of the other open issues. Most of these were minor, such as a debug …

Ever seen this in SHOW INNODB STATUS and wondered what it means?

-------------------------------------
INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 4634, seg size 4636,

I’ve never been quite sure, and Peter didn’t really clarify things himself, so I took a look at the source. If I’m not mistaken, the seg size is really one more than the number of records the insert buffer can hold, the free list length is the number that aren’t in use, and the size is just seg_size - (1 + free_list_len). These seem to be kept in lockstep as records are inserted and merged.

Related posts:

1. How to …

I wanted to provide an update on two things:

• Firstly, we have opened registration for InnoDB/XtraDB training in Los Angeles (Nov 18th).
• The second is that while I am in New York City for training (Oct 29th), I'll be giving a (free) talk at the MySQL Meetup group there (Oct 28th).

We love to speak at Meetup groups.  If you are an organizer feel free to let us know you are interested.  There's no guarantee that we can get schedules to align - but there are a number of Percona consultants that travel regularly.

Entry posted by …

This presentation was be done by Sheeri Cabral of The Pythian Group and went into how to use SHOW ENGINE INNODB STATUS to get more information about your Innodb tables, foreign keys and transactions. This is a great presentation to learn how InnoDB works.

It also went through how to use SHOW ENGINE INNODB STATUS to tune several InnoDB variables:

innodb_adaptive_hash_index
innodb_commit_concurrency
innodb_concurrency_tickets
innodb_file_io_threads
innodb_log_buffer_size
innodb_max_purge_lag
innodb_sync_spin_loops
innodb_thread_concurrency
innodb_thread_sleep_delay

The slides can be downloaded from:

http://technocation.org/files/doc/ShowEngineInnoDBStatus.pdf

(Note that the slides open up to the middle section, which …

At Days of Wonder we are huge fans of MySQL (and since about a year of the various Open Query, Percona, Google or other community patches), up to the point we’re using MySQL for about everything in production.

But since we moved to 5.0, back 3 years ago our production databases which hold our website and online game systems has a unique issue: the mysqld process uses more and more RAM, up to the point where the kernel OOM decide to kill the process.

You’d certainly think we are complete morons because we didn’t do anything in the last 3 years to fix the issue

Unfortunately, I never couldn’t …

For the my previous post, there was comment to suggest to test db_STRESS benchmark on XtraDB by Dimitri. And I tested and tuned for the benchmark. I will show you the tunings. It should be also tuning procedure for general heavy writing workloads.

At first, <tuning peak performance>. The next, <tuning purge operation> to stabilize performance  and to avoid decreasing performance.

<test condition>

Server:
PowerEdge R900, Four Quad Core E7320 Xeon, 2.13GHz, 32GB Memory, 16X2GB, 667MHz

db_STRESS:
32 sessions, RW=1, dbsize = 1000000, no thinktime

XtraDB: (mysql-5.1.39 + XtraDB-1.0.4-current)
innodb_io_capacity = 4000
innodb_support_xa = false
innodb_file_per_table = …