Update: Also read A brief update on NUMA and MySQL.

The “swap insanity” problem, in brief

When running MySQL on a large system (e.g., 64GB RAM and dual quad core CPUs) with a large InnoDB buffer pool (e.g., 48GB), over time, Linux decides to swap out potentially large amounts of memory, despite appearing1 to be under no real memory pressure. Monitoring reveals that at no time is the system in actual need of more memory than it has available; and memory isn’t leaking, mysqld‘s RSS is normal and stable.

Normally a tiny bit of swap usage could be OK (we’re really concerned about activity—swaps in and out), but in many cases, “real” useful memory is being swapped: primarily parts of InnoDB’s buffer pool. When it’s needed …

Some people seem unclear about whether there will be a 2011 MySQL conference from O’Reilly. There most definitely will be, and the CfP is open. We are looking for speakers. I’m on the speaker selection committee again this year for the Nth time, and my advice from past years still stands. This year we’re also looking for a greater diversity of database products, including other relational databases, NoSQL databases, and ancillary technologies.

MySQL Sunday at Oracle's Open world was a huge success given that it was MySQL's first year at the conference. I had a lot of fun and even a little excitement when a shirt caught fire during my presentation.

Just added a video to the site for MySQL High Availability. Check it out here if you missed it at MySQL Sunday, also, you can get the slides in PDF format here.

You can also check out all the other presentations here, brought to you by PalominoDB.

-- UPDATE --
9-29-10

Recently I was contacted by a fellow community member at Oracle who had some great …

Numerous times now, I’ve seen people have troubles creating MySQL services on Windows manually (using ‘sc’), whether it be for mysqld itself, MySQL Proxy, or the MySQL Enterprise Monitor and/or Agent.

The proper syntax for ‘sc’ can get tricky when you have spaces in pathnames, which is very common in Windows, and the need for –defaults-file (which means two paths each potentially containing spaces).

So, if you have spaces in both your binpath and your path to –defaults-file, then the following syntax will work for you (all on a single line):

sc create MySQLEnterpriseMonitorAgent 
binpath= ""C:Program FilesMySQLEnterpriseAgentbinmysql-monitor-agent.exe" 
--defaults-file="C:Program FilesMySQLEnterpriseAgentetcmysql-monitor-agent.ini"" 
DisplayName= "MySQL Enterprise Monitor Agent" start= "auto"

Note that you could easily use the exact same syntax to install a Windows service for the MySQL server itself …

While not as well known as the Google or Facebook patches the TiVo mysql patch includes some changes that make monitoring and query optimization a bit easier than mainline MySQL. The modified tarball, available at http://www.tivo.com/mysql/ contains a modified mysqld_safe, mysqldump, and improvements to the row statistics show commands that came from google.

mysqld_safe modifications

–fallback-ledir
The –ledir option tells mysqld_safe which directory contains the mysqld file that it should use. TiVo has added the –fallback-ledir option which will switch the ledir should mysqld crash. This makes it possible to run a new mysqld binary then fallback to the stock one should the new one crash. This feature has never been called to duty in production but it makes me sleep better.

–crash-script
This is a new option to mysqld_safe which will execute a script …

VIEWING THE DATA

You’ve seen in the last few postings how to find, import and use GIS data with MySQL. But, the ‘G’ in geographical includes GRAPHIC and a little eye candy never hearts your understanding of the curves.

Everyone knows of  map.google.com.  Mark McClure has a great site explaining the use of Google’s APIs.  He explains how to generate interactive maps with labels for places and routes indicating driving directions. Many of Mark’s example explain exactly the sorts of things I’ve wanted to do with maps for years.  Like Cycling routes on Google Maps.

Using the GPS in my iPhone as a …

Installing Lighttpd With PHP5 And MySQL Support On OpenSUSE 11.3

Lighttpd is a secure, fast, standards-compliant web server designed for speed-critical environments. This tutorial shows how you can install Lighttpd on an OpenSUSE 11.3 server with PHP5 support (through FastCGI) and MySQL support.

As part of “MySQL Sunday” at this year’s Oracle Open World, Mat Keep and I  presented on the MySQL Cluster architecture and the latest features. If you weren’t able to attend then you can watch/listen to the replay here.

Sonali Minocha, our world-renowned MySQL expert, lead a session on MySQL Performance Tuning: top 10 Tips on the third day of the conference.

Sonali, who is also famous for her MySQL performance tuning skills in the international community, bombarded the audience that comprised of DBAs and wannabe DBAs with a series of performance tuning tricks and best …

Thanks to Jayant, I had to clean coffee off my screen, but keyboard is a bit more tricky. This is Postgres advocacy at its best:

The base timings are almost 5 times more in mysql as compared to pgsql.

Then in comments, Harrison points out:

From the numbers, it is hard to believe that PostgreSQL is really fsync’ing properly there. I doubt a laptop HDD can do 1000 writes per second. Even assuming we have perfect group commit going on, with two threads it is still 500 per second for the first test.

InnoDB’s numbers are about right on for writes per second for a cheap commodity hdd.

Jayant’s answer is:

You may be right. But postgres is a more advanced and reliable database as compared to mysql.