In case you also want to replay the same dbSTRESS test scenarios I've posted results yesterday, I've added into the test kit a shell script which may be used as a Reference Scenario.
More details on how to use it is here .
As well dbSTRESS kit and User Guide are available for download
from http://dimitrik.free.fr
Forget to say, I've also tested PostgreSQL 8.3.7 during the last benchmark serie with dbSTRESS!
A big surprise - if two years ago on the same workload PostgreSQL was two times faster (see: http://dimitrik.free.fr/db_STRESS_BMK_Part2_ZFS.html ), now it's MySQL 5.4 outperforming PostgreSQL!
For more details: http://dimitrik.free.fr/db_STRESS_MySQL_540_and_others_Apr2009.html#note_5443
Forget to say, I've also tested PostgreSQL 8.3.7 during the last benchmark serie with dbSTRESS!
A big surprise - if two years ago on the same workload PostgreSQL was two times faster (see: http://dimitrik.free.fr/db_STRESS_BMK_Part2_ZFS.html ), now it's MySQL 5.4 outperforming PostgreSQL!
For more details: http://dimitrik.free.fr/db_STRESS_MySQL_540_and_others_Apr2009.html#note_5443
Having written about what I think is cool about the upcoming MySQL Conference and the MySQL Camp, now I want to finish up with what I’d like to see at the Percona Performance Conference. Just to recap, this is a conference we created to serve those who want to learn about performance — not “learn about MySQL,” not “learn about database performance,” just learn about performance, period.
I want to see everything. I think this is going to be the single best conference I’ve ever been to. Even the way the conference is organized is exciting. For example, it’s running from early morning till late at night, nonstop. The sessions are also (mostly) only 25 minutes. This means if you decide a session isn’t all that interesting, you didn’t spend much time on it, and you don’t have long to wait for the next one.
So here is a small sample of the …
[Read more]This is an issue that keeps rearing its ugly head over and over again, and since it greatly affects performance, it is most important that DBAs of any DMBS running on Linux come to grips with it. So I decided to do some research and try different settings on my notebook. Here are my findings.
What can you find on the web?
A Wikipedia search for the word swappiness will come up empty (any volunteers out there want to write an article?). A Google search will show some pretty old material—the best article I found is from 2004: Linux: Tuning Swappiness. This article includes a detailed discussion with some interesting remarks by Andrew Morton, a Linux kernel maintainer.
So, what is swappiness?
Towards the end of the email thread quoted in the article, you’ll find this definition (sort of):
> I’ve read the source for where …
[Read more]Welcome to the 142nd edition of Log Buffer, the weekly review of database blogs.
The SQL Server ’sphere was a busy place this week. On In Recovery… Paul S. Randall posted his latest straw poll, this time looking into your practices around transaction log size management.
Linchi Shea observed, “In a multi-process/multi-thread system, locking is central to maintain data consistency and keep things in order. . . . [We] need to begin with understanding the locking behavior of the basic building blocks offered by SQL Server . . . [One] would think that the basic locking behavior …
[Read more]
The break-up of the MySQL codeline is finally attracting
attention from polite society outside the open source database
community. This attention has been accompanied by much
speculation, some of it informed and some not so informed about what is driving the split. Since
everyone else is chipping in theories about how and why, here's
mine:
It's the economy, stupid.
First, MySQL AB seeded a huge market for the MySQL database.
MySQL 5.1 for …
WARNING: nearly every word of this post is intentionally false. This is an April Fool’s joke.
There is so much misinformation out there about how MySQL works. If you’ve talked to someone from PostgreSQL, you’ve surely heard some of it: “MySQL doesn’t even have transactions,” for example. And this from a PostgreSQL user, who uses a database that doesn’t even run on Windows.
But even within the ranks of people who supposedly know MySQL’s workings, lots of people just get things dead wrong. I wanted to set the record straight here, so I thought I would give a little walk-through of how MySQL executes a query.
Let’s see it in action from start to finish.
SELECT SQL_NO_CACHE COUNT(col1) FROM users WHERE userid IN( SELECT userid FROM othertbl ) ORDER BY userid DESC;
The steps to execute this query are as …
[Read more]In December 2007 Werner Vogels posted a blog article entitled Eventual Consistency, since updated with a new article entitled Eventually Consistent - Revisited. In a nutshell it described how to scale databases horizontally across nodes by systematically trading off availability, strict data consistency, and partition resilience as defined by the CAP theorem. According to CAP, you can only have two of three of these properties at any one time. The route to highly available and performant databases, according to Vogels, is eventual consistency in which distributed database contents at some point converge to a single value but at any given time may be …
[Read more]Welcome to the 141st edition of Log Buffer, the weekly review of database blogs. The Oracle bloggers were especially chatty this week, so let’s start with them.
Rob van Wijk wrote a fine post about choosing between SQL and PL/SQL, defending his choice of straight-up SQL for logic. Naturally, this triggered a lot of discussion, as well as a few responses from other blogs. Chen Shapira framed her response in a question about code life-cycle: would you rather maintain SQL or PL/SQL?
[Read more]