There are many angles you can look at the system to predict in performance, the model baron has published for example is good for measuring scalability of the system as concurrency growths. In many cases however we’re facing a need to answer a question how much load a given system can handle when load is [...]
Thinking about running OPTIMIZE on your Innodb Table ? Stop!
December 9, 2010 By 18 Comments
Innodb/XtraDB tables do benefit from being reorganized often. You can get data physically laid out in primary key order as well as get better feel for primary key and index pages and so using less space, it is just OPTIMIZE TABLE might not be best way to do it. If you’re running Innodb Plugin on [...]
MySQL Limitations Part 4: One thread per connection
October 27, 2010 By 14 Comments
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.
Caching could be the last thing you want to do
July 24, 2010 By 14 Comments
I recently had a run-in with a very popular PHP ecommerce package which makes me want to voice a recurring mistake I see in how many web applications are architected. What is that mistake? The ecommerce package I was working with depended on caching. Out of the box it couldn’t serve 10 pages/second unless I [...]
Scaling: Consider both Size and Load
July 13, 2010 By 5 Comments
So lets imagine you have the server handling 100.000 user accounts. You can see the CPU,IO and Network usage is below 10% of capacity – does it mean you can count on server being able to handle 1.000.000 of accounts ? Not really, and there are few reasons why, I’ll name most important of them: [...]
On Good Instrumentation
May 31, 2010 By 1 Comment
In so many cases troubleshooting applications I keep thinking how much more efficient things could be going if only there would be a good instrumentation available. Most of applications out there have very little code to help understand what is going on and if it is there it is frequently looking at some metrics which [...]
Is your server’s performance about to degrade?
May 18, 2010 By 13 Comments
I’ve been talking and writing a bit lately about the scaling problems I’m seeing on fast servers running lots of queries. As a rough guide, I’m seeing this in servers running 20k queries per second and higher, lots of memory, lots of CPU cores, and most queries are running faster than one millisecond; some in [...]
Why you should ignore MySQL’s key cache hit ratio
February 28, 2010 By 28 Comments
I have not caused a fist fight in a while, so it’s time to take off the gloves. I claim that somewhere around of 99% of advice about tuning MySQL’s key cache hit ratio is wrong, even when you hear it from experts. There are two major problems with the key buffer hit ratio, and [...]
Why Swapping is bad for MySQL Performance ?
January 18, 2010 By 11 Comments
So you get MySQL or other applications using too much memory on the box or OS behaving funny and using more memory for cache and pushing application to the swap. This causes swapping and causes performance problems. This much is obvious. But how bad is it ? Should you count it same as normal Disk [...]
MySQL-Memcached or NOSQL Tokyo Tyrant – part 1
October 15, 2009 By 16 Comments
All to often people force themselves into using a database like MySQL with no thought into whether if its the best solution to there problem. Why? Because their other applications use it, so why not the new application? Over the past couple of months I have been doing a ton of work for clients who [...]
