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Peter ZaitsevOne of the first rules you would learn about MySQL Performance Optimization is to avoid using functions when comparing constants or order by. Ie use indexed_col=N is good. function(indexed_col)=N is bad because MySQL Typically will be unable to use index on the column even if function is very simple such as arithmetic operation. Same can […]
Yesterday I’ve attended MySQL Customers Conference in London. This event is much smaller size than Users Conference (one day and about 170 people attending) and surely less geeky – there were no one from MySQL Development Support or Consulting teams and Sales Engineers were as close as you could get. Though Anders Karlsson and Ivan […]
The question I often get is how far MySQL may fall behind and how to keep replication from lagging. The lag you will see will vary a lot from application to the application and from load to load. Plus what is the most important within same application the lag will likely have spikes – most […]
I already wrote about this issue but as I is third team I’m helping customers to resolve this “frm corruption” issue it is the time to return to it again. During MySQL 5.0 release cycle the change was made so now MySQL does not stop if Innodb storage engine failed to initialize but starts properly… […]
Almost two weeks have passed since HighLoad 2007 conference in Moscow, Russia so I’m pretty late with feedback and my only excuse I was pretty busy to spare some time for it. Lets start with bright side. The conference had a lot of great sessions by experts in their field. A lot of top Russian […]
When I was comparing performance of UNION vs MySQL 5.0 index merge algorithm Sinisa pointed out I should be using UNION ALL instead of simple UNION in my benchmarks, and he was right. Numbers would be different but it should not change general point of having optimization of moving LIMIT inside of union clause being […]
About one month ago we posted a call for interns to work with us on various MySQL Performance related things. We got good number of replies and a lot of people wondered what tasks exactly we could offer as surely this sort of involvement should be fun and should teach you something.
Recent couple of days our team was pointed to number of bugs in MySQL 5.0 which again seriously shakes the confidence in both MySQL Quality Control and bug fix promptness. Let me just take couple of bugs as examples: Triggers broken with auto-increment columns for Innodb tables (bug 26316). As you can see this bug […]
Have you ever had a question about Innodb internal design or behavior which is not well covered in MySQL manual ? I surely had. Now you have a great chance to have them answered ! Heikki Tuuri, Creator of Innodb will answer your Questions about Innodb at MySQL Performance Blog. Please leave your questions as […]
Many Open Source software solutions use database per user (or set of tables per user) which starts to cause problems if it is used on massive scale (blog hosting, forum hosting etc), resulting of hundreds of thousands if not millions of tables per server which can become really inefficient. It is especially inefficient with Innodb […]
It always surprised me how little Innodb team seems to think about product usability/ease of use, when it comes to settings, performance management etc. I could understand many things 5 years ago, like a lot of information being available only in hard to parse SHOW INNODB STATUS output or even uglier hacks with creating tables […]
26th of September, just after HighLoad conference I will have full day MySQL master class. This time we will talk about Innodb Architecture and Performance Optimization and when will discuss some MySQL Performance Optimization and Scaling case studies from audience (or some of from my MySQL Consulting Practice if there would not be enough of […]
Every so often you need to perform sort results retrieved from MySQL when your WHERE clause goes beyound col=const values which would allow MySQL to still use second portion of the index for the order by. Ranges as well as IN lists make this optimization impossible, not even speaking about index merge optimization. Lets look […]
Quite typical query for reporting applications is to find top X values. If you analyze Web Site logs you would look at most popular web pages or search engine keywords which bring you most of the traffic. If you’re looking at ecommerce reporting you may be interested in best selling product or top sales people. […]
The more I work with MySQL Performance Optimization and Optimization for other applications the better I understand I have to less believe in common sense or common sense of documentation writers and do more benchmarks and performance research. I just recently wrote about rather surprising results with sort performance and today I’ve discovered even read_buffer_size […]
I finally got my visa so I’m going to MySQL Developers meeting in Heidelberg, Germany next week. Hopefully it will be great source of “technical insight” information, either from organized sessions or from developers themselves. Plus I’m looking forward meeting a lot of friends our where both MySQL Developers and active community members.
General query logging can be very handy in MySQL on profuction server for various debugging needs. Unfortunately you can’t switch it on and off without restarting server until MySQL 5.0. What can you do in MySQL 5.0 and below ? Use Our Patch – With this patch you can get all queries logged as slow […]
Quite frequently I run into question like this “I’m using SQL_NO_CACHE but my query is still much faster second time I run it, why is that ? The answer to this question is simple – because SQL_NO_CACHE only bypasses query cache but it has no change on other caches, which are MySQL Caches – Innodb […]
Monty Taylor posted interesting investigation of the fact read_buffer_size variable affects connection speed. This is not something you would expect right ? me too. Not only global user data is expected to be cached on startup but even if it is not why would you do full table scan to fetch single user information ? […]
As one of my last posts about issues with hosting provider got great response and We got a lot of good advice and offers I decided to ask for advice another problem we have as we’re growing our company – organizing good phone communications. Our goals are rather simple though the fact we’re globally distributed […]