I ran across this great experiment Kingpin tried testing how far one could go not signing your signature properly when making credit card purchases. He’s definitely proven a point and made a hilarious experience. A must read I must say.

Source: Drunk Republic: When Your Credit Card Signature Fun Backfires

In many cases I speculate how things should work based on what they do and in number of cases this lead me forming too good impression about technology and when running in completely unanticipated bug or performance bottleneck. This is exactly the case with LVM

Number of customers have reported the LVM gives very high penalty when snapshots are enabled (leave along if you try to run backup at this time) and so I decided to look into it.

I used sysbench fileio test as our concern is general IO performance in this case - it is not something MySQL related.

I tested things on RHEL5, RAID10 volume with 6 hard drives (BBU disabled) though the problem can be seen on variety of other systems too (I just do not have all comparable numbers)

O_DIRECT RUN

PLAIN TEXT CODE:

As Peter Gulutzan just announced - we’re opening up a “new” worklog that we’ve been working on, Worklog #2360. PERFORMANCE_SCHEMA.

In fact - it’s not “new”, it’s something that has been in the worklog system for a long time, and has had much much much discussion internally between some of the brightest engineers in the group.

The astute among you out there that read my post on the benchmark with Maria for the the tokutek challenge, may have noted this in the configure line that I used:

./configure –prefix=/usr/local/mysql –localstatedir=/data0/mysqldata \
–without-query-cache –with-extra-charsets=complex –with-pic …

We (Percona) just announced our Percona Performance Conference, and I wanted to tell you a little more about what we hope to accomplish with this conference. Let me show you some simple math that anyone can do. There’s a handy iCal download of the conference schedule on the conference website. iCal is a plain text format that is easy to parse with a scripting language. I downloaded this year’s and last year’s schedules, and aggregated the number of times each company and speaker is listed as presenting a session.

So far this year I’ve been totally silent about the MySQL Conference and Expo 2009. In the past I’ve been a vocal advocate of going to the conference and sending your employees to the conference. So my silence was conspicuous to me, if not to you. I’ve always considered myself a strong MySQL supporter and I still do. Why wasn’t I telling people to go to this year’s conference? Simple: I can’t in good conscience tell people to attend an event from which I’ve been excluded (oh, the irony).

Today we’re taking the wraps off the best MySQL feature of 2009:
Performance Schema. It monitors multitudinous low-level server
events and provides them in tables inside a new “database”
called, surprisingly, PERFORMANCE_SCHEMA. So far …

* It instruments mutex and disk io calls in the server and
in one of the storage engines.
* It times precisely (to the nearest cycle or nanosecond or
microsecond or tick depending on user choice).
* It has tables for “current event” by thread
(what the job is waiting for if it’s blocked).
* It has tables for “history of events” by thread
(what were the last N mutex or file io activities, and where).
* It has summaries by thread
(how many fractoseconds did this job spend on io since it started).
* It has summaries by object
(how many times has somebody read from file X).

On any operating …

All of us here at Percona warmly invite you to Percona Performance Conference 2009 on April 22 and 23, 2009 in the Hyatt Regency in Santa Clara, California. The theme for the conference is Performance Is Everything. This conference is about application performance overall, not just databases. Attendance is free of charge for everyone. Experts in many types of technologies -- databases, search, cloud computing, massively parallel computing, client-side optimization -- will present their real-life experience.

In order to forestall speculations and prevent people from jumping to unwarranted negative conclusions, I'd like to take a moment and explain the story behind this event. Some of you have noticed that there were no sessions from Percona this year on the schedule for the …

When I read Monty's post on leaving this passage struck me the most.

The main reason for leaving was that I am not satisfied with the way the MySQL server has been developed, as can be seen on my previous blog post. In particular I would have like to see the server development to be moved to a true open development environment that would encourage outside participation and without any need of differentiation on the source code. Sun has been considering opening up the server development, but the pace has been too slow.

In short, Sun isn't open enough. I think I've said that enough, it's typically more Open Core than Open Source .. and for a growing amount of people.. that isn't good enough.

Reacting on that post we see Matt Asay …

This new release of Gearman includes improved client library code, a few bug fixes, new benchmarking tools, and man pages for the API. I also changed the default port in this release to use our new IANA assigned port, 4730 (was previously 7003). This means if you try to mix existing APIs or job servers with this release, you’ll need to specify port options on one side to make sure they match up. You can find the new tarballs on the Gearman Download page or on Launchpad.

I’ve also released a new version of the Gearman MySQL UDFs due to some of the C library changes. You can find the updated tarballs on the Gearman Download page or on …