Baron makes an excellent point in Why you should ignore MySQL’s key cache hit ratio — ratio is not the same as rate. Furthermore, rate is [often] the important thing to look at.

This is something that, at Pythian, we internalized a long time ago when thinking about MySQL tuning. In fact, mysqltuner 2.0 takes this into account, and the default configuration includes looking at both ratios and rates.

If I told you that your database had a ratio of temporary tables written to disk of 20%, you might think “aha, my database is slow because of a lot of file I/O caused by writing temporary tables to disk!”. However, that 20% ratio may actually mean a rate of 2 per hour — which is most likely …

I've table contains text column and its charset is latin1, and i can store Arabic text ( and non English character) in this column and retrieve it, i don't know how is it?

So how is that? and why I need utf8?

CREATE TABLE `post` ( `postid` int(10) unsigned NOT NULL AUTO_INCREMENT, `threadid` int(10) unsigned NOT NULL DEFAULT '0', `parentid` int(10) unsigned NOT NULL DEFAULT '0', `

MySQL Cluster Performance Tuning Best Practices

Are you experiencing current performance bottlenecks in your high availability applications ? Are you designing a new mission-critical application and want to know how best to structure your schema and index strategy for optimal performance? Interested in how to transform your SQL into faster, more efficient queries?

Benefits of connection pooling

Then this free web presentation is for you! You will get expert insight and learn best practices to help you identify those areas of database and application design that will give you the greatest benefits for performance when using MySQL Cluster.

We will discuss guidelines and best practices covering the following areas:

• General Design Concepts and Guidelines
• Schema …

Since Ubuntu 8.04 aka Hardy Heron, I've had issues with every new release. As Ubuntu evolves into being a viable desktop OS alternative, its complexity has been growing and with the new and improved looks new challenges arise. This bug in particular has been very difficult to diagnose and I can't imagine anyone without enough Linux experience to overcome it on their own, so I decided to summarize the steps I took to fix it ... and vent my frustration at the end.
The SymptomI came across the issue for the first time while trying Ubuntu's Karmic Netbook remix. After overcoming the typical Broadcom wifi driver, Network Manager would connect, but Firefox would fail to load the web pages 90% of the time. Using ping in the command line worked just fine. Maybe I needed to update the software packages to get the latest patches, surprise, apt-get was having similar problems and timing out. So the problem …

The latest version of Kontrollbase – the opensource enterprise MySQL analytics and performance tuning application –  is available for download. Since the previous one, version 225, there have been a lot of great changes. The most significant being the development and inclusion of the Reporter CLI script – which is a combination of the client, [...]

There was a discussion on LinkedIn one month ago that caught my eye:

Database search by "within x number of miles" radius?

Anyone out there created a zipcode database and created a "search within x numer of miles" function ?
Thankful for any tips you can throw my way..

J

A few people commented that some solutions wouldn't scale. To understand why these sorts of geographic search queries are problematic in MySQL, it's best to show some execution plans on dummy data:

PLAIN TEXT SQL:

1. EXPLAIN …

I recently had the chance to witness the effects of innodb_adaptive_flushing on the performance of InnoDB Plugin 1.0.5 in the wild, which Yasufumi wrote about previously here and here.

The server in question was Solaris 10 with 8 disk RAID10 and 2 32GB SSDs used for ZIL and L2ARC, 72G RAM and 40G buffer pool. We started it up with innodb_adaptive_flushing=OFF and innodb_doublewrite=OFF, then ramped up traffic and everything looked stable ... but I noticed one troubling thing: ~2GB of uncheckpointed data.

mysql> SHOW INNODB STATUS\G
....
Database pages      2318457
Old database pages  855816
Modified db pages   457902
Log flushed up to   10026890404067
Last checkpoint at  10024612103454
....

We enabled …

Every time I need to install or reconfigure a new workstation, I review the set of tools I use. It's an opportunity to refresh the list, reconsider the usefulness of old tools and review new ones. During my first week at Open Market I got one of these opportunities. Here is my short list of free (as in 'beer') OSS tools and why they have a place in my tool chest.
Testing Environments
Virtual Box
Of all the Virtual Machines out there, I consider Virtual Box to be the easiest to use. Since I first looking into it while I was still working at Sun/MySQL, this package has been improved constantly. It's a must have to stage High Availability scenarios or run tools that are not available in your OS of choice.
MySQL SandboxDid you compile MySQL from source and want to test it without affecting your current …

There are a few parameters that may be worth looking at when first installing InfiniDB; NumBlocksPct for managing memory, PmMaxMemorySmallSide for optimizing join behaviors, and MaxOutstandingRequests which changes how individual queries share resources.

The NumBlocksPct parameter manages the amount of memory on each server allocated to store data blocks and is expressed as a % of server memory. For example, to allocate 5 GB for the data buffer cache for a server with 8GB memory, set thRead More...

There are a few parameters that may be worth looking at when first installing InfiniDB; NumBlocksPct for managing memory, PmMaxMemorySmallSide for optimizing join behaviors, and MaxOutstandingRequests which changes how individual queries share resources.

The NumBlocksPct parameter manages the amount of memory on each server allocated to store data blocks and is expressed as a % of server memory. For example, to allocate 5 GB for the data buffer cache for a server with 8GB memory, set thRead More...