My friend and a great sf author Dr Peter Watts has just been beaten up by US border guards and charged with assaulting an officer. This kangaroo circus might end with a two year imprisonment. Please give what you can to his legal defense fund.

Story:
Boing Boing

Send money via Paypal to:
donate@rifters.com

I just donated $50. Cory Doctorow gave $1000. Contesting criminal charges in US court gets very expensive, so every little bit matters.

At work, we’ve just put out the 9.7.1 refresh of DB2 Express-C. By all accounts, it’s a solid release. There’s a changelog here, and you can discuss it in the forum.

I recommend picking it up if you are running the free edition of DB2.

I’m hosting a workshop today at CASCON. The resources for it are below.

Materials

• Presentation (PDF, Slideshare)
• Exercises (PDF, Slideshare)

Resources

• IBM Smart Business Develop & Test on IBM Cloud
• Amazon Web Services (AWS)
• Rightscale
• MediaWiki Manual: IBM DB2

Downloads

• MediaWiki 1.16 build with DB2 support
• IBM Data Server Driver for ODBC and CLI
• IBM DB2 Express-C - Free database server

OLTP is a database use where there are lots and lots of simple transactions or queries. For example, a typical website uses a database in the OLTP way. This is in contrast to a data warehouse, where there is usually only a few complex queries for generating reports.

IBM just announced DB2 pureScale, a way of easily scaling up the number of transactions a database can handle. The scaling is horizontal, in the sense that it’s accomplished by adding more servers rather than making the servers bigger.

DB2 pureScale is:

• Transparent. Client applications don’t need to know how many database servers there are or which one they are accessing.
• Easy. Adding a new machine is a matter of running two commands.
• Resilient. If one node goes down, the other nodes take over and there is virtually no data loss.

There is an upcoming Chat with the Lab about it:

DB2 pureScale: Scaling Databases without Limits
Event Date: 10/21/2009
Event Time: 11:30 - 13:00 EDT (GMT-04:00)
Hosted By: Rav Ahuja (IBM)
Presented By: Sal Vella (IBM), Matt Huras (IBM), Aamer Sachedina (IBM)

Register now

MediaWiki 1.15 was released with partial DB2 support, but unfortunately there were some changes to the database schema that I missed and it didn’t work out of the box. Since then, I’ve committed several fixes to the main development trunk. The trunk is currently destined to become 1.16alpha, though theoretically I could backport these to the 1.15 branch.

• Download MediaWiki 1.16alpha (2009-09-23)
• Installation instructions
• Changelog

My Apache is currently crashing willy-nilly on startup. Hopefully, there are no silly development bugs left in.:-)

I ran into the following error while converting a virtual machine on a VMWare ESX Server to OVF using the VMWare OVF Tool.

Disk Transfer Failed
Error: Unable to open NFC target disk

Googling suggested that a network problem or a permissions problem might be at fault. In fact, it turned out the problem was that someone had started the image on the ESX server mid-way through conversion. The OVF Tool cannot convert a running image — it requires a stopped machine. Stopping the vm made the problem go away.

In the future, we might all say “updation”.

Here’s how you solve either of the following errors on Ubuntu (and possibly Debian):

device br0 already exists; can't create bridge with the same name
device eth0 is already a member of a bridge; can't enslave it to bridge br1.

Removing the device specs from /etc/network/interfaces and restarting the network doesn’t actually remove the device if already active. You need to do it manually.

List the active devices:

And then do this to any that you don’t want there, such as br0, eth0, eth1, etc:

This deactivates the device. At this point you’ll need to restart the network layer twice:

And you should be sitting pretty. On some systems, networking is known as network, as in:

No fresh download quite yet, but I just made a large commit to the MediaWiki source of the last week’s work. This is going in the trunk — aka MediaWiki 1.16alpha. There are a few bugs I hope to catch this weekend, at which point I’ll put up a fresh archive of working code.

config/index.php:
* Made installation on IBM DB2 more robust
* Replaced E_ALL error reporting mode with E_ALL | E_STRICT

includes/db/DatabaseIbm_db2.php
* Enabled DB2_CASE_LOWER option for all connections and statements
* Enabled DB2_DEFERRED_PREPARE_ON for all statements — delays statement preparation until execution to reduce database load
* Enabled DB2_ROWCOUNT_PREFETCH_ON for all statements — makes db2_num_rows() work correctly
* Cleaned up error handling
* Cleaned up method signatures
* Rewrote insertion to use prepared statements — required for inserting more than 32k of text
* Insertion will never try to insert a NULL value into a primary key
* Now relying on implicit casting in DB2 9.7 — no longer sniffing to see if column is integer or string before adding quotes
* Implemented actual prepared statement handling — required for correct INSERT, UPDATE behaviour
* In install mode, the class will print additional messages to the install bullet scroll
* Added bitwise operation abstraction (BITNOT, BITAND, BITOR)

includes/specials/SpecialAncientpages.php
* Added skeleton DB2 syntax to the database-specific switch statement

maintenance/convertLinks.inc
* Made limit clause database-agnostic

maintenance/ibm_db2/README
* Contents replaced with link to http://www.mediawiki.org/wiki/Manual:IBM_DB2

maintenance/ibm_db2/tables.sql
* Revised types to better match the main schema
* All tables names now the same as MySQL — was using Postgres schema’s names before
* Added some additional indices
* Added the change_tag, tag_summary, valid_tag, user_properties, log_search, and l10n_cache tables
* Added several new columns

maintenance/storage/compressOld.inc
* Made limit clause database-agnostic

DB2 caches your machine’s hostname in several places. If your machine is changing its hostname, or if you are somehow moving an existing installation to a machine with a different hostname, you will need to adjust the hostname stored by DB2. Hostname change is common in virtual and cloud environments, so even better than adjusting it would be writing a script that adjusts it for you.

Here’s my rudimentary stab at a such a script:

This doesn’t cover all cases. For example, if you use extended operating system security, you may also need to set the db2accountname and db2instowner parameters. A quick check with db2set -all should tell you if this applies in your case — if there is something that looks like a hostname in those parameters already, you need to change them.

I may also have missed other necessary changes. Please let me know if I did.:-)

References

• IBM Support | Changing hostname of DB2 server
• Fillmore Group | Changing the hostname of a DB2 server
• Diary of a Database Geek | The importance of db2nodes.cfg

Edit: Revised to use proper authorities, incorporate official instructions