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Displaying posts with tag: Tech (reset)

Using the MySQL Test Suite
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Earlier I reported about two crashes related to MySQL 5.0.22 on Ubuntu 6.06 LTS.

I think those bugs show a lack of testing on the side of Cannonical/Ubuntu. And for MySQL there is a quite good test suite available, so it's not rocketsience.

There are multiple reasons why you could use the MySQL Test Framework:
1. Test if bug you previously experienced exists in the version you are using or planning to use.
2. Test if configuration changes have a good or bad result on the stability of mysqld.
3. Test if important functions still return the correct results …






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Another Crash in MySQL 5.0.22 on Ubuntu 6.06 LTS
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1. Set this variable
thread_stack = 265K

2. Execute this query
mysql> SELECT 0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0
+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+
0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0
+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+
0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0
+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+










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Crash in MySQL 5.0.22 on Ubuntu 6.06 LTS
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I found a new crasher in the MySQL 5.0 version which ships with Ubuntu 6.06 LTS.

> SELECT * FROM (SELECT mu.User FROM mysql.user mu UNION SELECT mu.user FROM mysql.user mu ORDER BY mu.user) a;
ERROR 2013 (HY000): Lost connection to MySQL server during query

The bug report: LP392236

On MySQL 5.0.51 on Debian stable it returns this error (like it should):
ERROR 1054 (42S22): Unknown column 'mu.user' in 'order clause'

The correct query should be like this (Using culumn a number):
> SELECT * FROM (SELECT …










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MySQL scanning module for Metasploit
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I've created a very simple MySQL scanning module for the metasploit framework.

1. Download the mysql_version file and rename it to mysql_version.rb and put it in the framework-3.2/modules/auxiliary/scanner/mysql directory of your metasploit installation.
http://compukid.no-ip.org/dev/scripts/mysql_version

2. Use using msfcli
./msfcli auxiliary/scanner/mysql/mysql_version RHOSTS=192.168.0.1 E
[*] 192.168.0.1:3306, MySQL server version: 5.0.81-1-log (Protocol 10)

3. More options:
set THREADS to 10 and RHOSTS to 192.168.0.0/24 to scan a whole network.

Hibernate Wars: The Query Cache Strikes Back
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Not so long ago, in a galaxy not very far away... a middle-aged programmer battled to free memory from the dark side of the hibernate query cache.  He was successful, or so it seemed. For the query cache memory problems had risen from the ashes -- stronger and more bloated than ever...


What's With All This Garbage?
We hit a case at work (again), where the java server process came to a grinding halt.  It wasn't dead, it just wasn't making much forward progress either.  A quick look at the heap stats showed we were …



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Arbitrary Replication/Proxy Topologies with MySQL Sandbox
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How would you like to use MySQL Sandbox to deploy and test any replication topology imaginable? Do you want to describe load balancer and proxy configurations, too? If you already love sandbox (or even if you don't), and you want to play with arbitrarily complex replication/proxy topologies... read on.

Sandbox Is Your Friend

MySQL Sandbox is a great tool. As of this writing, version 3 is feature complete -- and the new features are greatly desired. Replication support has been there a while for …



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Database Sharding at Netlog, with MySQL and PHP
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This article accompanies the slides from a presentation on database sharding. Sharding is a technique used for horizontal scaling of databases we are using at Netlog. If you’re interested in high performance, scalability, MySQL, php, caching, partitioning, Sphinx, federation or Netlog, read on …

This presentation was given at the second day of FOSDEM 2009 in Brussels. FOSDEM is an annual conference on open source software with …

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Database sharding at Netlog (FOSDEM talk slides)
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Here are the slides from yesterday’s presentation about horizontal database scaling through sharding at the mySQL dev room at FOSDEM 2009.

I’ve got a ton of notes and remarks to these slides, which will become available here soon.

Artem’s Top 10 Tech Predictions And Ideas For 2009 And Beyond
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Everyone and their mother are throwing out their predictions for 2009 nowadays, it’s a new fad. It’s like you’re not cool anymore if you don’t have twitter, a Mac, and a set of random predictions for the next 12 joyous months.

So I decided to throw in a few ideas of my own to be part of the cool crowd again (how much cooler can I be already, you might think, and I wouldn’t blame you).

 

Disclaimer (read it, tough guy)

What this post is:

  • about the future of technology and the Internet, 2009 and beyond.
  • my ideas on what is …
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Hibernate Query Cache: A Dirty Little Secret
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You Mean, Memory Is Not Infinite?We're working hard getting MySQL Enterprise Monitor 2.0, featuring Query Analyzer, ready for release. As part of that, we started really ramping up the number of MySQL servers reporting in query data to see how we could scale. Not surprising (to me, anyway), the first efforts did not go so well. My old friend OutOfMemoryError reared its ugly head once again.
Query Cache -- It's More Than Just Results! We're big (ab)users of hibernate query caching, and more importantly to us the …

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10 Newer Entries Showing entries 31 to 40 of 63 10 Older Entries

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