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Displaying posts with tag: Programming (reset)
Fixing MySQL group commit (part 1)

This is the first in a series of three articles about ideas for implementing full support for group commit in MariaDB (for the other parts see the second and third articles). Group commit is an important optimisation for databases that helps mitigate the latency of physically writing data to permanent storage. Group commit can have a dramatic effect on performance, as the following graph shows:

The rising blue and yellow lines show transactions per second when group commit is working, showing greatly improved throughput as the parallelism (number of concurrently running transactions) increases. The flat red and green lines show transactions per second with no group commit, with no scaling at all as parallelism increases. As can be seen, the effect of group commit on …

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Debugging memory leaks in plugins with Valgrind

I had an interesting IRC discussion the other day with Monty Taylor about what turned out to be a limitation in Valgrind with respect to debugging memory leaks in dynamically loaded plugins.

Monty Taylor's original problem was with Drizzle, but as it turns out, it is common to all of the MySQL-derived code bases. When there is a memory leak from an allocation in a dynamically loaded plugin, Valgrind will detect the leak, but the part of the stack trace that is within the plugin shows up as an unhelpful three question marks "???":

==1287== 400 bytes in 4 blocks are definitely lost in loss record 5 of 8
==1287==    at 0x4C22FAB: malloc (vg_replace_malloc.c:207)
==1287==    by 0x126A2186: ???
==1287==    by 0x7C8E01: ha_initialize_handlerton(st_plugin_int*) (
==1287==    by 0x88ADD6: plugin_initialize(st_plugin_int*) …
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Reviewed: Python Testing by Daniel Arbuckle

I’ve recently had the pleasure of reading “Python Testing: An easy and convenient approach to testing your python projects” from Packt Publishing. It’s been a quick read but a solid set of instructions on the different methods for the subject.

The book starts out very quickly with details about the various methods that are available, the means of automation for testing, and of course the environment you’d want to be in for working on the subjects that the book covers. It then, in the second chapter, moves into the guts of testing by describing the basics of doctest via syntax and some simple examples, and then moves on to a real world example via the AVL tree. It’s all very basic testing until chapter three where the author gets into unit testing, …

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Event based programming vs threading by Rob von Behren, Jeremy Condit and Eric Brewer

Saw this interesting paper about highly concurrent programming methods and figured the word should be spread! It’s not new material but it’s a good read. See the full article here:

“Highly concurrent applications such as Internet servers and transaction processing databases present a number of challenges to application designers. First, handling large numbers of concurrent tasks requires the use of scalable data structures. Second, these systems typically operate near maximum capacity, which creates resource contention and high sensitivity to scheduling decisions; overload must be handled with care to avoid thrashing. Finally, race conditions and subtle corner cases are common, which makes debugging and code maintenance difficult.

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Four short links: 31 March 2010
  1. ZeroMQ -- bold claim of "Fastest. Messaging. Ever." LGPL, C++ with bindings for many languages, past version 2 already. (via edd on Twitter)
  2. Prediction Market News (David Pennock) -- HSX is going to be a real marketplace with real $. The real HSX will of course say goodbye to the virtual specialist and the opening weekend adjust, two facets of the game that make it fun to play, but that create significant amounts of (virtual) wealth out of thin air. The Cantor Gaming group is engaged in other interesting initiatives. They are taking over a sportsbook in Las Vegas and turning it into more of a derivatives exchange with live in-game betting, a step toward my dream of a geek-friendly casino. …
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Kontrollcomm – remote database and system command execution webapp

I’m pleased to announce the first release of Kontrollcomm – “The Server Command Automation Interface” is a web-based application that automates remote command execution on linux and unix based servers. There are three main areas of the application: Hosts, Templates, and Commands. The use is very simple: all of your hosts are setup in the [...]

Reviewed: Managing Software Development with SVN and Trac

I’ve recently been migrating my wiki/documentation for Kontrollbase to Trac. For those that are not aware, Trac is a web-based documentation/wiki/Subversion tool that is used by countless number of software projects. Subversion, of course, is a software collaboration and code management repository that manages branches/tags/trunk files with revision control. It’s one of the most heavily used open-source code repositories available. Given that I use SVN (subversion) for all of my software applications and am now using Trac, the book “Managing Software Development with Trac and Subversion” by David J Murphy comes as a useful and great resource for integrating these two useful tools. …

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Building MySQL Server with CMake on Linux/Unix

CMake is a cross-platform, open-source build system, maintained by Kitware, Inc.

From the home page:

CMake is a family of tools designed to build, test and package software. CMake is used to control the software compilation process using simple platform and compiler independent configuration files. CMake generates native makefiles and workspaces that can be used in the compiler environment of your choice.

It has been used for building the MySQL Server on Windows since MySQL 5.0 – the initial CMake build support was added in August 2006.

For …

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Kontrollkit – new version is available for download!

Just a quick notice to let everyone know that there is a new version of Kontrollkit available. There are two new scripts included as well as some good updates to the my.cnf files. You can download the new version here: kt-mysql-systemcheck – generates a report for point-in-time system status that is useful for troubleshooting MySQL [...]

Tech Messages | 2010-02-24

A special extended edition of Tech Messages for 2010-02-20 through 2010-02-24:

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