Imagine that two colleagues, Alice and Bob, issue a command to launch a new virtual machine at approximately the same moment in time. Both Alice’s and Bob’s virtual machines must be given an IP address within the range of IP addresses granted to their project. Let’s say that range is 192.168.20.0/28, which would allow for a total of 16 IP addresses for virtual machines [1]. At some point during the launch sequence of these instances, Nova must assign one of those addresses to each virtual machine.

How do we prevent Nova from assigning the same IP address to both virtual machines?

In this blog post, I’ll try to answer the above question and shed some light on issues that have come to light about the way in which OpenStack projects currently solve (and sometimes fail) to address this issue.

Demonstrating the …

First of all, Happy New Year!

IEEE Spectrum published a ranking of the most popular programming languages. Computational journalist Nick Diakopoulos wrote the article. While it may surprise some, I wasn’t surprised to find SQL in the top ten.

Nick weighted and combined 12 metrics from 10 sources (including IEEE Xplore, Google, and GitHub) to rank the most popular programming languages.

• Compiled programming languages (Java [#1], C [#2], C++ [#3], C# [#4], Objective-C [#16])
• Interpreted programming languages (Python [#5], JavaScript [#6], PHP [#7], Ruby [#8], Perl [#11], HTML [#12])
• Data languages (SQL [#9], MATLAB …

Recently while writing a data loading application for a customer, we’ve come into a problematic situation with the Python MySQLdb module that can be installed with base RHEL repository or DVD. As a little background, this application uses an HA architecture where a Virtual IP can be assigned to different servers during a failover scenario. However, during failover, as long as the VIPs are not re-assigned, the application could hang waiting for query response. A quick strace reveals something like:

sendto(5, "W\0\0\0\3SELECT * FROM dataloader.bo"..., 91, 0, NULL, 0) = 91
recvfrom(5,

Further test reveals that this problem will not timeout until after about 15 minutes which matches the default tcp_retries2 value on the system (see man 7 tcp):

[root@node1 ~]# cat /proc/sys/net/ipv4/tcp_retries2
15

It turns out that this version of MySQLdb module has client net read and write timeouts set to 0 allowing the TCP setting …

This year’s MySQL Central at Oracle Open World was an exhilarating experience. In contrast to the previous year’s MySQL Connect events, MySQL have now got their own Central at the main Oracle Open World. In the previous years, we were always short on time and trying to get a lot of sessions into just two days was just to much. This time I could both present sessions, attend sessions by other users, and also to talk to people in the MySQL community: something that I really enjoy and also find very valuable to see where we should be heading.

This year, the “MySQL Fabric Team” representation on MySQL Central was me and Narayanan Venkateswaran, which is heading the sharding solution in MySQL Fabric. Together with the conference, we also released MySQL Fabric 1.5.2 as the GA release of MySQL Fabric 1.5 containing a few new features:

• Server …

In time for Oracle OpenWorld 2014, we released Connector/Python 2.0. We also released a labs release Connector/Python 2.1 and we have a new feature: a C Extension which uses Connector/C.

This C Extension is an optional, an alternative to the pure Python MySQL Client protocol implementation. One of the reasons to implement it was to improve performance in some situations, for example, when huge result sets are returned. Pure Python is still default, if C Extension is not available.

The following post will get your through downloading and installing the MySQL Connector/Python 2.1.0 labs release.

Requirements

• Windows users out of luck; the labs release only compiles on Linux, OSX …

In time for Oracle OpenWorld 2014, we released Connector/Python 2.0. We also released a labs release Connector/Python 2.1 and we have a new feature: a C Extension which uses Connector/C.

This C Extension is an optional, an alternative to the pure Python MySQL Client protocol implementation. One of the reasons to implement it was to improve performance in some situations, for example, when huge result sets are returned. Pure Python is still default, if C Extension is not available.

The following post will get your through downloading and installing the MySQL Connector/Python 2.1.0 labs release.

Requirements

• Windows users out of luck; the labs release only compiles on Linux, OSX and other …

Both MySQL Connector/Python 2.0.1 and 1.2.3 are now available through the Python Package Index or PyPI. Leaving the previous version available is probably a good idea as you can always go back if needed.

Note that we still have no files hosted at PyPI.

Both MySQL Connector/Python 2.0.1 and 1.2.3 are now available through the Python Package Index or PyPI. Leaving the previous version available is probably a good idea as you can always go back if needed.

Note that we still have no files hosted at PyPI.

We have relocated the MySQL Connector/Python repository on GitHub to the following location:

https://github.com/mysql/mysql-connector-python

The old location will redirect to the above URL.

No, we have not updated the README.txt or made something special for GitHub. I personally don’t mind what is currently showing on GitHub: it is readable, and it is correct. I still hope GitHub will make it easier to show something else, like asking which document to display and as what format.

MySQL Connector/Python v2.0 goes GA with version 2.0.1 GA. It is available for download from the MySQL Developer Zone! The previous post about 2.0 described what changed and what was added, here’s an overview:

• Incompatibilities
  • Supported Python: 2.6 and 2.7 and 3.3 and 3.4
  • Raw Cursors Return bytearray Objects
  • LOAD LOCAL DATA INFILE On by Default
• New features
  • New Cursors return dictionaries and named tuples
  • Options Files Support Added
• Packaging and support files removed
…