The follow-up blog post on moving your MySQL applications to CouchDB has been posted on the CouchOne blog. Part 2 digs into a bit more detail on the specifics of views, and how to perform some of the more common operations used in MySQL, such as paging and aggregation in your CouchDB view.

You can read Part 2 here

CRIB is a CentRal Information Base for MySQL, a long time coming project since I worked on it on and off for a few weeks and now I decided it’s time to hand it over to the global MySQL community.

So, what is CRIB?

CRIB is a central database which collects information about all your MySQL instances which you set as clients. It is monitoring in a way, but not the typical number of connections, memory, index usage, table scans, cpu usage and such, but rather consists of a repository where, if you have tens, hundreds or even thousands of clients, you can see where a particular user was created, where a certain database name features or which tables does a database consists of. It also features a script which logs table sizes periodically (customizable) so you can graph disk usage over time and be able to forecast future disk space requirements easily.

Download the latest code with: bzr branch lp:crib

First …

I’ve started a little series on how to migrate your MySQL applications and databases over to CouchDB. Most of the process is about how you think about your data, not about the database itself, the application, or the interface to the database storage. There are some use cases for data storage that lend themselves to the CouchDB document model that provides some advantages over the table-based structure in MySQL. The first part of the series is Moving from MySQL to CouchDB: Part 1.

Just as a friendly reminder about what I wrote a month ago: we've already received a number of great talk submissions for the MySQL & Friends Developer Room at FOSDEM 2011, thanks to everyone who contributed so far! However, we still are looking for some more!

You can submit your proposal via this form. The deadline for turning in your talk is Sunday, 26th of December, 2010.

Just to recapitulate, the DevRoom (H.2213) will be available to us on …

I’ve started a little series on how to migrate your MySQL applications and databases over to CouchDB. Most of the process is about how you think about your data, not about the database itself, the application, or the interface to the database storage. There are some use cases for data storage that lend themselves to the CouchDB document model that provides some advantages over the table-based structure in MySQL.

The first part of the series is Moving from MySQL to CouchDB: Part 1.

Originally submitted at O’Reilly

Server bottlenecks and failures are a fact of life in any database deployment, but they don’t have to bring everything to a halt. MySQL provides several features that can protect you from outages, whether you’re running directly on the hardware, on virtual machines, or in the cloud. This…

MySQL High Availability

Good coverage of MySQL and replication

By sjmudd from Madrid, Spain on 11/24/2010 4out of 5

Pros: Easy to understand, Accurate, Well-written, Concise, Helpful examples

Best Uses: Intermediate, Expert

Describe Yourself: Sys Admin, Database Administrator

I work in quite a …

An update of MySQL from 5.0 to 5.5 on CentOS 5.5 64bit has not resulted in a good experience. The mysqld process would then crash every few minutes with the following message.

101120 8:29:27 InnoDB: Operating system error number 22 in a file operation.
InnoDB: Error number 22 means ‘Invalid argument’.
InnoDB: Some operating system error numbers are described at
InnoDB: http://dev.mysql.com/doc/refman/5.1/en/operating-system-error-codes.html
InnoDB: File name /tmpfs/#sql6cf3_5c_0.ibd
InnoDB: File operation call: ‘aio write’.
InnoDB: Cannot continue operation.

The work around was to change the tmpdir=/tmpfs (which was a 16G tmpfs filesystem) to a physical disk.

The referenced URL didn’t provide any more information of help. Unlike Bug #26662 O_DIRECT is not specified as the flush method.

One significant new feature of MySQL 5.5 is the Performance Schema. I recently performed an upgrade from 5.0 to 5.5, however my check of differences in the MySQL variables via mysqladmin variables failed because we now have a new record long variable name “performance_schema_events_waits_history_long_size”.

The full list of new performance_schema variables are:

> | performance_schema_events_waits_history_long_size | 10000                                                                                                                  |
> | performance_schema_events_waits_history_size      | 10                                                                                                                     |
> | performance_schema_max_cond_classes               | 80 …

So your not a MySQL DBA, but you have to perform like one. If you have a production environment that’s running now, what are the first things you do when it’s not running or reported as not running?

1. Are the MySQL processes running? (i.e. mysqld and mysqld_safe)
2. Can you connect locally via cli?
3. What’s in the MySQL error log?
4. What are current MySQL threads doing? Locked? long running? how many? idle sources?
5. Can you connect remotely via cli?
6. Verify free diskspace?
7. Verify system physical resources?
8. If this is a slave, is MySQL replication running? Is it up to date?
9. What is the current MySQL load, e.g. reads/writes/throughput/network/disk etc?
10. What is the current InnoDB state and load? (based on if your using InnoDB)

After you do this manually more then once you should be scripting these commands to …

Dear Kettle fans,

PDI-200 has been out there for a while now.  Jens created the feature request a little over 3 years ago.  I guess the main thing blocking this issue was not as much a technical problem but more of a licensing and dependency one (Oracle JDBC dependency and distribution license).

However, now that we have the User Defined Java Class step we can work around those pesky problems. That is because the Java code in there only gets compiled and executed at runtime so it’s perfectly fine to create any sort of dependency in there you like.

The following transformation reads a set of rows from a stored procedure as described on this web page.

In short, our UDJC step executes the following code:

begin ? := sp_get_stocks(?); …