October 31, 2014

Guidance for MySQL Optimizer Developers

I spend large portion of my life working on MySQL Performance Optimization and so MySQL Optimizer is quite important to me. For probably last 10 years I chased first Monty and later Igor with Optimizer complains and suggestions. Here are some general ideas which I think can help to make optimizer in MySQL, MariaDB or […]

Four ways to optimize paginated displays

A paginated display is one of the top optimization scenarios we see in the real world. Search results pages, leaderboards, and most-popular lists are good examples. You know the design pattern: display 20 results in some most-relevant order. Show a “next” and “previous” link. And usually, show how many items are in the whole list […]

The MySQL optimizer, the OS cache, and sequential versus random I/O

In my post on estimating query completion time, I wrote about how I measured the performance on a join between a few tables in a typical star schema data warehousing scenario. In short, a query that could take several days to run with one join order takes an hour with another, and the optimizer chose […]

MySQL Optimizer team comments on TPC-H Results

Yesterday I had a chance to speak to Igor – head of MySQL optimizer team and Timur – both of them expressed concern with TPC-H run results I posted and notes about little gains in MySQL 6.0. Do not get this post wrong. I’m not saying MySQL 6.0 SubQuery optimizations are non existent or priorities […]

Using delayed JOIN to optimize count(*) and LIMIT queries

In many Search/Browse applications you would see main (fact) table which contains search fields and dimension tables which contain more information about facts and which need to be joined to get query result. If you’re executing count(*) queries for such result sets MySQL will perform the join even if you use LEFT JOIN so it […]

Is it query which needs to be optimized ?

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 first and then think how the queries they […]

MySQL Optimizer and Innodb Primary Key

Innodb primary key is special in many senses and I was always wondering how well MySQL is integrated with Innodb to take advantage of these special features. Lets see which things work and which things do not:

Visualization tools for pt-query-digest tables

When you process MySQL slow query logs using pt-query-digest you can store samples of each query into query_review table and historical values for review trend analysis into query_review_history table. But it could be difficult to easily browse those tables without a good GUI tool. For the visual browsing of tables created by pt-query-digest you may […]

Looking forward to Oracle OpenWorld 2014; visit us at Booth 2413!

I’m excited to once again be heading to San Francisco next week for Oracle OpenWorld, and also very pleased to have a booth there this year along with some great speakers from Percona. The scope of Oracle OpenWorld 2014, which runs Sept. 28-Oct. 2, is enormous and there are several keynotes and sessions I’m looking […]

MySQL upgrade best practices

MySQL upgrades are necessary tasks and we field a variety of questions here at Percona Support regarding MySQL upgrade best practices. This post highlights recommended ways to upgrade MySQL in different scenarios. Why are MySQL upgrades needed? The reasons are many and include: Access to new features, performance benefits, bug fixes…. However, MySQL upgrades can […]