After some fiddling around with the alternatives, I convinced myself that Gearman is the way to go. Before I proceed to show what I did, though, perhaps it's useful if I spend a few words about Gearman …

This week I've had to revisit merge tables once again due to customers experiencing problems. Although 5.1 merge table implementation is a huge improvement over 5.0, there still remains some critical bugs.

My list is still growing:

bug #45800: crash when replacing into a merge table and there is a duplicate
bug #45781: infinite hang/crash in "opening tables" after handler tries to open merge table
bug #45796: invalid memory reads and writes when altering merge and base tables
bug #45777: check table doesn't show all problems for …

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.

Learn how GlassFish and NetBeans helped Ginga community to build a TV Banking application in Brazil. See a live demo of the product, it's really exciting!

Why GlassFish ? - They love how NetBeans tooling completely hides the complexity of what's happening underneath and the ease-of-use with GlassFish.

Thanks Hugo Lavalle for the interview and good luck with your product!

Technorati: conf fisl brazil glassfish …

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 this message and exit
       -H, --hostname=<hostname> The target MySQL server host
       --ignore-databases …

This was reported in The Reg. That is one of my favorite sites. I don't know whether the contents of the article reflect what was said, but the topic is critical to anyone hosting a rapidly growing business on MySQL.

http://www.theregister.co.uk/2009/06/26/facebook_server_slam

Prior to the SMP patch for InnoDB from Google (now in the InnoDB plugin and MySQL 5.4), it was very easy to show that throughput on an 8-core server was much slower than on a 4-core server for a CPU-bound workload with a lot of concurrency. That has begun to change. My vague memory is that we were able to show about 1.25X speedup from 4 to 8 to 16 cores on sysbench (meaning 16-cores is more than 2X faster than 4).

All of the problems have not been fixed. There are still several hot mutexes in InnoDB (kernel_mutex, commit_prepare_mutex) and in MySQL (LOCK_table, the MyISAM index cache mutex, the HEAP engine mutex, group commit is still broken in InnoDB …

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:

http://dev.mysql.com/downloads/workbench/5.1.html

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 Millsap was making it understood, …

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 it contribute to the badness score?

Let’s think of another …

Learn how GlassFish and NetBeans helped Ginga community to build a TV Banking application in Brazil. See a live demo of the product, it's really exciting!

Why GlassFish ? - They love how NetBeans tooling completely hides the complexity of what's happening underneath and the ease-of-use with GlassFish.

Thanks Hugo Lavalle for the interview and good luck with your product!

Technorati: conf fisl brazil glassfish …