The latest from the MySQL community

I am now sitting in on MySQL and Search at Craigslist by Jeremy Zawodny at MySQL Users Conference

Some of the technical difficulties that required addressing.

• High churn rate
• half life can be very short
• Growth
• Traffic
• Need to archive postings, e.g. 100M but be searchable
• Internationalization and UTF-8

Some of the Craigslist Goals

• Open Source
• Easy and approachable
• be green with energy use

A review of the Internals server configuration

• Load Balancer (perlbal like)
• Read Proxy Array (perl+memcached)
• Web Read Array (apache 1.3 + mod_perl)
• Object Cache (Perl + memcached)
• Read DB Cluster …

I find it surprising that in the official Sun Announcement there is no mention of MySQL for two reasons. Firstly, this was Sun largest single purchase of $1 billion only 12 months ago. Second, MySQL’s largest competitor is Oracle.

While the Sun website shows the news in grandeur, the MySQL website is noticeably absent in any information of it’s owners’ acquisition.

On my professional side, as an independent speaker for Sun Microsystems with plans for upcoming webinars and future speaking on “Best Practices in Migrating to MySQL from Oracle”, this news does not benefit my bottom line.

When you have to evaluate a MySQL System & Environment, what questions do you ask in order to determine critical information about the environment and evaluate the business success and viability. You don’t have to be a consultant to ask these questions, ask them of your own environment. Do any of the answers shock or concern you?

I was prompted to write about this from a conversation with a colleague about “accepting risk”. His comment was, “every IT server on the planet is vulnerable regardless of best practices.”

Here is my list of questions for you based on an immediate response from this discussion?

Technology

• What is your full technology stack, i.e. Operating System, Database, Application Server, Development Language(s) and other essential components?
• What are the versions of these technologies?
• What new technologies or versions of existing technologies are you …

A new feature to MySQL Version 5 was the introduction of SQL_MODE to support STRICT… or TRADITIONAL values.

This feature enabled a closer compatibility to other RDBMS products. MySQL by default performs a number of silent data changes which do not help in providing a level of data integrity if you come from a more traditional background. MySQL by default represents these as warnings, while with an appropriate SQL_MODE, these are in turn treated as errors.

How does Drizzle handle this? Very simple. There is no SQL_MODE. By default Drizzle handling a strict mode of producing errors for any invalid data. The following are some test case examples showing the varying conditions.

Test Case

select version();
create database if not …

Continuing on from CPU, we turn our attention to Memory. One of the first steps when addressing a MySQL performance tuning problem is to perform a system audit of the physical hardware resources, then identify any obvious bottlenecks in these resources.

In auditing, I start with the ‘free’ command, the already used ‘vmstat’ command, the /proc/meminfo and /proc/sys/vm/swappiness files to get an indication of memory and swap resources. While we are looking at the Memory, the configuration of Swap is also very important. I will discuss this in more detail later.

$ free -m
             total       used       free     shared    buffers     cached
Mem:          3955       3838        117          0        402       2366
-/+ buffers/cache:       1069       2886
Swap:         1027          0 …

Assuming you have successfully compiled Drizzle, and you are ready to start for the first time, here are some beginner differences with those familiar with the current MySQL 5.1 GA version. Note: drizzle is actually an original fork of the 6.0.x codebase however the code looks very little like mysql anymore.

Getting started differences

The first default MySQL installation step scripts/install_mysql_db is gone, and there is no replacement. The ‘mysql’ schema no longer exists. Talking about schemas, ‘test’ is also gone by default.

While a bin/drizzled_safe exists to start drizzle, this presently doesn’t operate as expected. You should start drizzle with sbin/drizzled &

They still have an empty …

Taking the work already done with vmplot.sh, a useful tool for MySQL performance tuning by Yves and Matt at BigDBAHead, and in true Open Source fashion I’ve enhanced and modified for my own purposes.

These changes include:

• Error checking for ‘gnuplot’ command on the system
• Eliminate the first row of sample data, as this is often not a complete sample for the vmstat duration.
• Created a HTML output file for easy browser viewing
• Changed Memory scale values from Kilobytes to Megabytes
• Resizing png’s for optimal 1024×768 display output (2 per row)

Download vmplot

And I get:

So more specifics of what I did.

Install gnuplot.

$ yum install gnuplot

Create vmstat sample …

One of the first steps when addressing a MySQL performance tuning problem is to perform a system audit of the physical hardware resources, then identify any obvious bottlenecks in these resources.

When dealing with CPU, a quick audit should include identifying the number of CPU cores your server has, and the types of these cores. The key file on Linux systems is /proc/cpuinfo.

Number of cores can be found via the command cat /proc/cpuinfo | grep “^processor” | wc -l

You need to look more closely at the file to determine the type of CPU (e.g. below the model name shows Intel(R) Xeon(R) CPU X3220 @ 2.40GHz. The combination of knowing the number of processors (cores) listed and physical id and siblings helps identify how many CPUs and how many cores per CPU exist.

$ cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model …

While working with Monty Widenius on a bug I reported in MariaDB I was surprised to not get an IRC response for a few minutes. When committed Monty can identify, create a workaround, and patch a problem in code before you have time to read all the responses he also types. See my Monty’s Monument “Passion is a timeless wisdom” comment. One thing I forgot to say in that entry was, while 9pm in New york, it was at last 3am-5am Monty time.

We all love memorable quotes, so here is one.

“sorry, machine died; First time in years”

[9:40pm] montywi: then just try compiling mysqld.o, no need to wait for everything else...
....
[9:58pm] rbradfor: make is clean.
[9:59pm] montywi: sorry, machine died;  First time in years
[10:00pm] rbradfor: laughs …

Today I come back from the dentist, if that wasn’t bad enough news, I get an email from Google AdWords titled Your Google AdWords Approval Status.

In the email, all my AdWords campaigns are now disapproved, because of:

SUGGESTIONS:
-> Ad Content: Please remove the following trademark from your ad:
mysql.

Yeah right. I can’t put the word ‘MySQL’ in my ads. How are people to now find me? It would appear that many ads have been pulled not just mine. Is this a proactive measure by Google? is this a complaint from the MySQL trademark holder Sun Microsystems?

I’d like any comment, feedback or suggestions on how one can proceed here.

It reminds me of the days CentOS advertised itself as an “Open source provider of a popular North American Operating System”, or something of that nature.