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SELECT vs select

I spent way too much time this weekend trying to get the pager stuff in Drupal working for a module I`m playing with.

I had learned a lot from the watchdog module on how paging was supposed to be working and I was trying to do the same with another database. As I got a page limited by the number of records I wanted but I couldn't find any of the fancy next, previous and page number thingies that I wanted.

The watchdog module worked for me and I started stripping the watchdog module till I could actually replace my function with watchdog_overview function. Even replaced the watchdog query with my qeury.. but not such luck.. I couldn't get $output .= theme('pager', NULL, 50, 0); to work.

So as every open source geek does.. I started looking into the code. pager.inc
The header told me the author.. I could mail him and wait …

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Why publish on Lulu.com ?

Arjen wonders why the MySQl Cluster Study book is published on Lulu and not trough MySQL 's traiditional publisher.

Altough I was involved in the creation process of the mentionned book, I have no idea why this decision was made but to me it makes perfect sense. MySQL Cluster is a piece of software that is still going to change a lot in the next couple of months and years.
A book published in a traditional way needs a minimal sales volume in order to be worth publishing. If there even is a slight chance that by the time the book gets published a significant amount of content of the book has already changed traditional publishers shouldn't publish the book. Now over at Lulu.com a book won't be print before a customer orders it. So when the book is being sent to me. I get the current version of the book.. If in 3 months the authors decide to rewrite a chapter or …

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Falcon serendipitous performance findings

While researching partitioning performance (expect an article about this topic soon) I come across the news that the Falcon team has released a Falcon Feature Preview with the latest implementation.
The test I was running was based on 9 server instances , using different combinations of MyISAM, InnoDB, and Archive, with and without partitions.
Since I was at it, I quickly added three instances of MySQL 6.0.4 with Falcon (MySQL Sandbox is really handy in these cases) and added Falcon to the test bench.
As I expected, partitioned Falcon is not particularly impressive, but there was a serendipitous result. In addition to large data warehouse oriented queries, the test fires also 180 OLTP queries, with warm indexes, i.e. after the indexes have been …

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My Wishlist - Do you have a product you can recommend?

One of the concepts of clustering, is that the secondary node may need to stonith the primary node in a forced take over in order to make it give up shared resources. This works great on more expensive hardware that has a management interface like IPMI, but my 'toys' budget is a little more limited.

It's equally possible to just cut the node off at it's power source. Does anyone know of a (cheap) power strip with a serial[1]/usb[1]/network interface where I can send signals to cut off individual ports power?

If I can't switch off individual power ports, I will need to buy two and have the nodes each manage the opposite node's power.

[1] If it's serial or USB I'll need to use a third node as a proxy to the device, which is annoying, but quite possible.

MySQL's cluster cert study guide - on lulu?

Hmm, dunno if anyone else spotted this interesting tidbit... the new MySQL Certification study guide, the one on MySQL Cluster, is made available via Lulu: http://www.lulu.com/content/1297960

MySQL AB used to have a deal with Pearson, branded as MySQL Press.
Lulu.com on the other hand is a self-publishing system.
I've seen other Lulu books, the printing and binding is quite excellent. No worries there.

But what this means is that apparently the Pearson deal ended somehow and MySQL AB hasn't got another publisher. I find that a bit curious. The problem is of course that now you're not likely to see this study guide appear in any shops. Online is fine, but shop-based distribution doesn't hurt, particularly with the "competition" databases having plenty of related books on the shelf. Diddums for Amazon & co, it's now just not there. So people …

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Thoughts on hashes.... libmemcached...

Inside of libmemcachd (aka the library behind the memcache engine for MySQL) I have a big stack of hash algorithms you can pick to use. libmemcached splits hashing into two concepts.

Hash used for key distribution
Algorithm used for distribution

For the hashing there is a default method that I use. It is pretty generic in nature. There are two other primary methods are MD5 and Hsieh.

So what does the performance look like for each of these?

Default:
Testing generate_data                           14.183
Testing get_read                                     11.144
Testing mget_read                                        1.992
Testing mget_read_result …
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MySQL Proxy: a chassis and a MySQL-server

At MySQL I'm writing several different command-line applications from the MEMo Agent to the MySQL Proxy. They all have a common set of requirement:

  • command-line options
  • config-files (mapping cmd-line options to config-files)
  • logfile handling (syslog, SIGHUP, ...)
  • a mainloop (SIGINT, CtrlHandler, ...)
  • daemonizing (daemonize, services, ...)
  • plugin handling

In the proxy svn you see all this a the chassis of the proxy.

At the side it has a MySQL-Server and a MySQL-Client (we usually call it the proxy). Currently this is implemented as libmysql-proxy which is then used by the proxy plugin to implement the proxy.

By splitting up the design into 3 different layers:

  • chassis
  • low-level protocol + protocol states
  • proxy implementation as plugin

we can

  1. use the …
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Wishlist for partitioning

I love the way partitioning works in MySQL. I remember in the past how many projects I implemented using application logic to parallelize I/O. Partitioning makes this seamless now. But it's not without its share of problems and workarounds. So I compiled my own wishlist that hopefully might make it into a future version of MySQL.

1. Partition level table locking. Partitions should be treated like tables and locked individually rather than the who table and all of its partitions.
2. Ability to add partitions from existing tables. This is very ueful, especially when trying to perform bulk maintainance operations.
3. Ability to convert a partition to a table.
4. Be able to mix and match storage engines for partitions and subpartitions. How cool would it be to have an archive partition for older data reside using ARCHIVE tables while the remaining partitions are InnoDB or MyISAM.
5. More usuable datatypes for …

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Buying the guide

Just to say I’ve bought the book as soon as it was available on lulu.com.

I was waiting for it from april.

Falcon serendipitous performance findings

While researching partitioning performance (expect an article about this topic soon) I come across the news that the Falcon team has released a Falcon Feature Preview with the latest implementation.
The test I was running was based on 9 server instances , using different combinations of MyISAM, InnoDB, and Archive, with and without partitions.
Since I was at it, I quickly added three instances of MySQL 6.0.4 with Falcon (MySQL Sandbox is really handy in these cases) and added Falcon to the test bench.
As I expected, partitioned Falcon is not particularly impressive, but there was a serendipitous result. In addition to large data warehouse oriented queries, the test fires also 180 OLTP queries, with warm indexes, i.e. after the indexes have been …

[Read more]