When I started with MySQL 3.22 I would start running MySQL from early beta (if not alpha) and update MySQL the same date as release would hit the web. Since that time I matured and so did MySQL ecosystem. MySQL is powering a lot more demanding and business critical applications now than 12 years ago […]
Core file can be quite helpful to troubleshoot MySQL Crashes yet it is not always easy to get, especially with recent Linux distributions which have security features to prevent core files to be dumped by setuid processes (and MySQL Server is most commonly ran changing user from “root” to “mysql”). Before you embark on enabling […]
MySQL 5.5 and Percona Server 5.5 do not solve all scalability problems even for read only workloads. Workloads which got a lot of attention such as Sysbench and DBT2/TPC-C scale pretty well a they got a lot of attention, there can be other quite typical workloads however which do not scale that well. This is […]
I wrote about MySQL Error Messages before and as you might guess I’m not very happy with quality for error messages it produces. Now I’m revisiting this subject with couple of more annoying examples I ran into during last couple of days.
mysql> drop database test;
ERROR 1010 (HY000): Error dropping database (can't rmdir './test/', errno: 17)
Much has been written about tools to inspect Linux systems, and much has been written about Solaris’s Big Important Tools such as DTrace. But I don’t recall seeing much in the MySQL blogs about basic tools to find one’s way around a Solaris system and discover the system, get fundamental performance, configuration, and status information, […]
I’ve been working with an application which does a lot of CREATE and DROP table for Innodb tables and we’ve discovered DROP TABLE can take a lot of time and when it happens a lot of other threads stall in “Opening Tables” State. Also contrary to my initial suspect benchmarking create/drop table was CPU bound […]
Ewen and I have just published Percona’s latest white paper, Forecasting MySQL Scalability with the Universal Scalability Law. This is essentially a streamlined walk-through of Dr. Neil J. Gunther’s book Guerrilla Capacity Planning, with examples to show how you can apply it to MySQL servers. One thing alluded to in the paper is extracting the […]
This is the third in a series on what’s seriously limiting MySQL in core use cases (links: part 1, 2, 3). This post is about the way MySQL handles connections, allocating one thread per connection to the server.
The parameter sort_buffer_size is one the MySQL parameters that is far from obvious to adjust. It is a per session buffer that is allocated every time it is needed. The problem with the sort buffer comes from the way Linux allocates memory. Monty Taylor (here) have described the underlying issue in detail, but basically above […]
After having reviewed the definition my the previous post (The definitions), the next step is to respond to some questions. Do you need MySQL High-Availability? That question is quite obvious but some times, it is skipped. It can also be formulated “What is the downtime cost of the service?”. In the cost, you need to […]