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Displaying posts with tag: Linux (reset)
451 CAOS Links 2011.04.21

DoJ/FCO says aye CPTN. Canonical readies Ubuntu 11.04. And more.

Follow 451 CAOS Links live @caostheory on Twitter and Identi.ca, and daily at Paper.li/caostheory
“Tracking the open source news wires, so you don’t have to.”

# Novell-CPTN patent sale agreed by DoJ/FCO, subject to the patents being licensed to OIN.

# VMware reported net income of $126m in Q1 on revenue up 33% to $844m.

# Canonical previewed Ubuntu 11.04, featuring Unity and also Ubuntu Server 11.04.

# The Open Invention Network …

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Setting up replication with XtraBackup

I attended Vadim Tkachenko’s talk on XtraBackup during MySQL conference in Santa Clara last week. Backups are obviously very important, but the use case I had in mind is this:
Replicating a database that has Innodb tables in it, while keeping both master and slave on line if possible.

Tangent: by the way, I love the native backup utility that was once promised in MySQL 6.0, similar to SQL Server’s way of backup. It was like running “BACKUP myDb to DISK = ‘/backupDirectory/myDb.bak'” under mysql client, but I digress…

I have used mysqldump to accomplish this in the past, but I wondered how XtraBackup would fare in this task, especially after hearing Vadim’s talk and reading news on Percona’s development effort. To cut to the chase, this is my conclusion. Reproducing steps are listed immediately afterwards.
1. …

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Oracle is not to blame for Sun’s open source failings

Oracle announced on Friday that it is to discontinue its commercial interest in the OpenOffice.org project, prompting a barrage of criticism from the open source faithful with regards to its approach to the open source applications project, and community in general.

The company was accused of being community-hostile, for example, and comparisons were also made to Colonel Gadhafi, while a translation of the press release into “plain English” apparently shed new light on the announcement.

In truth though, the language …

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NoSQL, NewSQL and Beyond: The answer to SPRAINed relational databases

The 451 Group’s new long format report on emerging database alternatives, NoSQL, NewSQL and Beyond, is now available.

The report examines the changing database landscape, investigating how the failure of existing suppliers to meet the performance, scalability and flexibility needs of large-scale data processing has led to the development and adoption of alternative data management technologies.

Specifically, the report covers:

  • NoSQL databases designed to meet scalability requirements of distributed architectures and/or schema-less data management requirements, including big tables, key value stores, document database and graph databases
  • NewSQL databases designed to meet scalability requirements of distributed architectures or to improve performance such that horizontal scalability is no longer a necessity, including new MySQL storage engines, transparent sharding technologies, …
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451 CAOS Links 2011.04.15

VMware launches Cloud Foundry. Red Hat heads for Ceylon. And more.

Follow 451 CAOS Links live @caostheory on Twitter and Identi.ca, and daily at Paper.li/caostheory
“Tracking the open source news wires, so you don’t have to.”

# VMware launched Cloud Foundry Platform-as-a-service and open source project.

# Red Hat’s Gavin King revealed details of the company’s Ceylon project.

# Red Hat submitted a number of specification requests for Java EE 7.

# Terracotta accused Red Hat of “trying to pull a fast …

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Slides: Linux and H/W optimizations for MySQL

On Monday I presented 3-hour tutorial "Linux and H/W optimizations for MySQL" at the MySQL Conference and Expo 2011, and published the slides at SlideShare.

451 CAOS Links 2011.04.12

Groklaw declares victory. Cloudera updates Hadoop distro. And more.

Follow 451 CAOS Links live @caostheory on Twitter and Identi.ca, and daily at Paper.li/caostheory
“Tracking the open source news wires, so you don’t have to.”

# Groklaw claimed victory, will stop publishing new articles on May 16.

# Cloudera released version 3 of its Hadoop distribution.

# VoltDB released version 1.3 of its open source distributed in-memory database.

# Black Duck grew sales by 51% in Q1.

# eXo and Convertigo …

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Install MySQLdb module for Python

Update:

Commenter MarkR made a great point: if possible, use some packaging tools, to try to maintain proper dependencies, to the extent that is possible. Install from the source should be Plan B. So, try yum install MySQL-python first.

This is mostly for my own future reference. It’ll be icing on the cake if it helps you!

This is geared for CentOS or Red Hat. Use apt-get or other packaging tools for different flavours of Linux.

1. Get Python module setuptools called easy_install. I love easy_install, by the way, sort of like CPAN for Perl modules;
2. To install MySQLdb package, you would think easy_install MySQLdb would do. But that is not the case. I hope the developer would fix that. Instead, you need:

easy_install MySQL-python

3. If you have build errors, you may need:
yum install python-devel or yum …

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MySQL and RAMdisk, or how to make tmpdir-usage queries faster

Have you ever looked at your processlist and seen queries in the state “copying to tmp table” and then run an explain on it and noticed that the tmp table is being created on disk? Happens a lot with some servers and some workloads. Of course disk is much slower than RAM so this becomes a slow process and makes queries execute slower than they could if they were allowed to use RAM. So, one way to get this process to speed up (aside from tuning your queries which should be done first) is to create a tmpfs or ram-disk and let MySQL use that for it’s temp-table-on-disk creations. MySQL on Linux defaults to /tmp for the tmpdir location so this will need to be changed.

Here is how you get MySQL to use a 1G size tmpfs. How you size your tmpfs depends how much ram your system has and how much tmpdir space mysql needs for your workload. If you need more tmpdir space than you can make in a tmpfs mount then mysql allows multiple tmpdir locations …

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SELinux and “failed to map segment from shared object” error

I am reading and following examples in MySQL 5.1 Plugin Development. After compiling and moving a .so file (think DLL or Assembly file in Windows) into MySQL plugin directory, I got this message when I tried to create a UDF (User Defined Function):

mysql> create function udf_staticexample returns integer soname 'udf_staticexample.so';
ERROR 1126 (HY000): Can't open shared library 'udf_staticexample.so' (errno: 0 /usr/lib/mysql/plugin/udf_staticexample.so: failed to map segment from shared object: Permission denied)

This is caused by the fact that the .so shared object file is not in the right SELinux security context:

[root@asusfedora plugin]# ll -Z
lrwxrwxrwx. root root …
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