by Peter Zaitsev | Mar 13, 2007 | Insight for Developers
I get a lot of mail and I prefer to store it for long time if not forever. With modern hard disk sizes it should not be problem at all, but because of how mailing programs are written it causes a lot of problems. I’ve tried a lot of programs – Kmail,...
by Peter Zaitsev | Mar 7, 2007 | Insight for DBAs
Today I was cloning the master using LVM Snapshot and found it was taking quite a while to catch up, which highlighted replication could be the limiting factor for this system quite soon, so I decided to check what is limiting MySQL Replication speed. My first idea...
by Peter Zaitsev | Mar 6, 2007 | Insight for Developers
Last few days I had a lot of a lot of questions at MySQL Performance Forum as well as from our customers regarding query optimization… which had one thing in common – It is not query which needed to be optimized. Way too frequently people design schema...
by Peter Zaitsev | Mar 5, 2007 | Insight for DBAs
Where does real power of MySQL Storage Engines, and pluggable storage engines as MySQL 5.1 lays ? It is very much advertised this allows third parties to create their own storage engines and we can see solutions as Solid and PBXT . Plus there is Falcon storage engine...
by Peter Zaitsev | Feb 27, 2007 | Insight for Developers
Performance optimization is never ending story, you can virtually always find something else to optimize but while on generic system, not tuned by expert you often can get significant performance increase in the matter of hours further performance improvements become...
by Vadim Tkachenko | Feb 25, 2007 | Insight for DBAs
We often recommend to our clients to convert their current database from MyISAM tables to InnoDB. The transfer by itself in most cases is almost plain, however the application can be broken by new unexpected errors 1205 (ER_LOCK_WAIT_TIMEOUT) Lock wait timeout...
by Peter Zaitsev | Feb 20, 2007 | Percona Events
About half a year have passed since me and Vadim have left MySQL to do MySQL Consulting on our own. Bunch of people have been wondering about our experiences so I thought it would be worth to share it here. Feels Good. I always liked to be my own boss and funny enough...
by Peter Zaitsev | Feb 19, 2007 | Insight for Developers
In MySQL 5.0 mainly error control was improved, such as strict mode was added to change famous MySQL behavior of cutting too large strings, too big numbers and allowing you to use dates such as February 31st. In one case however reverse change was done – in...
by Peter Zaitsev | Feb 16, 2007 | Insight for Developers
One interesting problem with MySQL Optimizer I frequently run into is making poor decision when it comes to choosing between using index for ORDER BY or using index for restriction. Consider we’re running web site which sell goods, goods may be from different...
by Peter Zaitsev | Feb 14, 2007 | Insight for DBAs
I was working with customer today which has MySQL on a system with some 64GB or RAM running MyISAM, so they set key_buffer_size to 16G… and every few days MySQL crashes. Why ? Because key_buffer_size over 4GB in size is not really supported (checked with latest...
by Peter Zaitsev | Feb 14, 2007 | Insight for Developers
MySQL Replication is asynchronous which causes problems if you would like to use MySQL Slave as it can contain stale data. It is true delay is often insignificant but in times of heavy load or in case you was running some heavy queries on the master which not take...
by Peter Zaitsev | Feb 11, 2007 | Insight for Developers
This week I helped dealing with performance problems (part MySQL related and part related to LAMP in general) of system which does quite a bit of content delivery, serving file downloads and images – something a lot of web sites need to do these days. There were...
by Peter Zaitsev | Feb 8, 2007 | Insight for DBAs, MySQL
Have you ever seen a connection in the SHOW PROCESSLIST output which is in “Sleep” state for a long time and you have no idea why this would happen? MySQL Sleep I see if frequently with web applications and it is often indication of trouble. Not only it...
by Peter Zaitsev | Feb 5, 2007 | Insight for Developers
I already wrote kind of about same topic a while ago and now interesting real life case makes me to write again 🙂 Most Web applications we’re working with have single tier web architecture, meaning there is just single set of apache servers server requests and...
by Peter Zaitsev | Jan 31, 2007 | Insight for DBAs
There is one bug, or “missing feature” in MySQL Optimizer which may give you hard time causing performance problems which may be hard to track down, it is using only part of the index when full index can be used or using shorter index while there is longer...
by Peter Zaitsev | Jan 30, 2007 | Hardware and Storage
Found a great article about Linux IO Schedulers today which is quite interesting. It goes in details about schedulers and explains in which of workloads which of schedulers is best. The interesting thing this article points out is – there are multiple versions...
by Peter Zaitsev | Jan 30, 2007 | Insight for DBAs
Kevin Burton writes about making MySQL Replication Parallel. Many of us have been beaten by the fact MySQL Replication is single threaded so in reality it is only able to use only single CPU and single disk effectively which is getting worse and worse as computers are...
by Peter Zaitsev | Jan 19, 2007 | Insight for DBAs
We all know disk based temporary tables are bad and you should try to have implicit temporary tables created in memory where possible, do to the fact that you should increase tmp_table_size to appropriate value and avoid using blob/text columns which force table...
by Peter Zaitsev | Jan 19, 2007 | Percona Events
It looks like it looks like there are going a lot of discussions about future of MySQL Community Binaries, see for example this post and Kaj’s clarifications. Obviously now it grew to a lot of speculations and many comments are far from real story. It is also...
by Peter Zaitsev | Jan 18, 2007 | Insight for Developers
Jonathan Haddad writes about REPLACE INTO and INSERT ON DUPLICATE KEY UPDATE. Really, Why MySQL has both of these, especially both are non ANSI SQL extensions ? The story here seems to be the following – REPLACE INTO existed forever, at least since MySQL 3.22...
