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The Daily WTF collects excellent tales from the real world. These days, the dismal dramatic sagas are often (at least in part) about mistakes involving databases; no surprise there, they’re so prolific…
Anyway, if you can learn from other people’s mistakes, that’s cheap and efficient education! I thought I’d share today’s edition with you: it’s called Death by Delete. Read and enjoy^H^H^H^H^Hlearn.
With the growing adoption of Google’s User Statistics Patch**, the need for supporting scripts has become clear. To that end, we’ve created check-unused-keys, a Perl script to provide a nicer interface than directly querying the INFORMATION_SCHEMA database.
check-unused-keys can be invoked and used as follows:
%> check-unused-keys --help
Usage:
check-unused-keys [OPTIONS]
Options:
-d, –databases=<dbname> Comma-separated list of databases to check
-h, –help Display [Read more...] We’re proud to announce the availability of our 3rd Release Candidate of MySQL Workbench 5.1. This is the last Release Candidate before 5.1 is released as GA. We keep optimizing and improving the functionality and brushing the last rough corners to be able to provide a shiny Workbench 5.1 GA next week. You can find the details as always on this release on our Releases Page.
Head right over to our Download page to give this last development build a try:
If you encounter any problems, please report them to our bugtracker. Feel free to contact us any time on IRC (irc.freenode.net, #workbench) for any questions or infos.
- The Workbench Team
Welcome to the 151st edition of Log Buffer, the weekly review of database blogs. We’re going to take a fast tour through the best blogs from the week gone by, beginning this time, with Oracle.
Jonathan Lewis writes, “It occurred to me recently that I might be making casual use of terms that weren’t necessarily very well known to the less experienced user. So I’ve decided to build a glossary of terms – and I’ll try to add to it from time to time whenever I have a few minutes.”
Jonathan might want to add “Method R” to the glossary. Cary
[Read more...]Suppose that you’re writing a new Maatkit tool (just a random example, really) and its job is to measure the difference in execution of queries. The simplest metric is execution time.
Now suppose that you’re trying to figure out a metric of badness. The query executes in a second on machine 1 and 1000 seconds on machine 2. That’s a pretty bad change. How do you quantify this?
Now you’ve got a query that executes in 1ms on machine 1, and 10ms on machine 2. It’s a tenfold change. Is it a bad change? Maybe it’s just the difference in which files were cached in memory, or network latency because someone flooded the TCP pipe and the packets had to be backed off and retried, or something like that. Is this significant? How should
[Read more...]Introduction
MySQL Server (starting from v 5.0), as Oracle and SQL Servers, allows creating stored procedures and functions.
Stored procedures are a set of SQL commands that can be compiled and stored on the server. Thus instead of storing a frequently-used query, we can refer to a corresponding stored procedure. This provides better performance (as this query is analyzed only once) and reduction of traffic between client and server.
While developing business logic of procedures, we often use a great number of variables (e.g., temporary outputs) to store. To assign static values to a variable or values of other variables, SET operator is used. SET operator in stored procedures is an
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I reported a bug about SHOW BINLOG EVENTS not working with relay logs a couple of years ago - Bug #28777.
It’s now been fixed in MySQL 5.4, by adding a new SHOW statement - SHOW RELAYLOG EVENTS.
The replication team are really hammering through things at the moment - Kudos!
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this is source code for a tiny program I just wrote that traverses specified directories and removes them from file system cache.
There are few use cases for it. One is for all these people who benchmark stuff and want selective OS cache purges, another is for those who run high performance databases. Remember the O_DIRECT serialization everywhere? Well, XFS does direct I/O in parallel, unless there are cached pages (and they can happen because of any random outside-of-database activity, like ‘file’ command). Once you ‘uncache’ the files, XFS will be very much parallel again \o/ \o/
Reanimating the Sydney MySQL User Group!
What: Sydney MySQL User Group meetup #7 - The Reboot
When: July 16, 2009 5:30 PM (please don’t forget to RSVP yes/no/maybe)
Where: Sydney, CBD - join the meetup for exact location.
We are back! After 3 years of being silent, SMUG (can I call it so? I know there are conflicts with other acronyms) resurrects the meetings.
The logistic of the meetup is the following:
A new version of the DRBD User’s Guide is up at http://www.drbd.org/users-guide. As this version has some major additions to the previous release, I’ve decided to create a release
candidate this time, before declaring this an “official reference” — everyone’s feedback is requested and highly encouraged.
What’s new is Chapter 8, “Integrating DRBD with Pacemaker clusters“. It deals with the new drbd OCF resource agent we are about to release with 8.3.2, and how to use it in Pacemaker clusters using the CRM shell. It also has setup examples for MySQL, as does the legacy chapter on Heartbeat. Please grab
The call for papers for OSDC 2009 is open until 30 June 2009; yes that’s only a few more days. Submit your abstract and do a talk at this fab conference!
This is a grassroots style conference designed by developers for developers. It covers Perl, Python, Ruby/Rails, PHP, Java/Grails and Open Source operating systems as well as some business aspects. If you’d like to cover something else as well that is Open Source themed, please feel free.
The Call for Papers can be found at: http://2009.osdc.com.au/call-for-papers
The important dates are:
OSDC
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OQ Engineer Walter Heck working from Samara, Costa Rica
Life as a Location Independent Professional can be hard at times, and very good at others!
Where are you going to invest your time and money. You may invest in your kids, your work, your hobbies, and more. As you make these decisions, your passion is one consideration, but another is the return on your investment. Of course, you want your investments to be successful. The best way to ensure success is to bet on winners. In other words, you want to invest your time and money on things you are confident will be successful. This holds true in your personal and your professional life.
When Alexandre Dumas (on a side note, my wife refers to me regularly as a Dumas) said that "Nothing succeeds like success" he was encapsulating this same decision process and the conclusion that people want to bet on winners, and that by so doing, they are perpetuating that winning.
So what does this have to do with open source software (OSS)? I received a note from Roland
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My old friend and collaborator Theo Schlossnagle at OmniTI posted his slides from his Scalable Internet Architectures talk at VelocityConf 2009.
The slides are brilliant even without seeing Theo talk and I highly recommend the time it takes to flip through them, for anyone who is interested in systems performance. If anyone took an mp3 of this talk I’m dying to hear it, please let me know.
For those of you unfamiliar with OmniTI, Theo is the CEO of this rather remarkable company specializing in Internet-scale architecture consulting. They generalize on Internet-scale architecture, not on one specific dimension the way Pythian specializes on the database tier. This allows them to see Internet-scale workloads from a unique systemic, multidisciplinary point of view; from the user experience
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On the MySQL Proxy channel we get questions from time to time if the authentication can be intercepted and replaced data from a external source.
From now on, you can. For example if you want to get data from a external source (like LDAP) or want to implement roles.
There isn't much needed to implement Roles for MySQL with the help of the MySQL Proxy.
mysql.user doesn't contain users, but roles insteadIt works like this:
login to the proxy
$ mysql --user=jan --password=secret --port=4040
proxy looks up username password, finds a role for him
Just a quick note to say I'll be giving a 1 hour webinar on performance tuning practices for MySQL at 1pm EST, 10am PDT today. Here is a link to sign up for it:
http://www.mysql.com/news-and-events/web-seminars/display-373.html
Hope to see you on the webinar 
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