I’ve noticed a few blog posts recently about people saying how great DRBD is as a fail over mechanism for MySQL. My experience with DRBD has been the complete opposite. It offers almost no benefit over binary log replication for typical MySQL setups and prevents a few things that are possible with binary log replication.

Kaj Arnö has written an excellent blog post on the basics of DRBD. DRBD has one great feature that binary log replication doesn’t have. It can ensure that a write is synced to disk on two different hosts before allowing the application to continue. This is great for data redundancy but it introduces potential for instability in the setup. In a good fail over scenario a problem on the backup master should never cause an issue on the primary master. With DRBD the second master lagging behind because of a degraded raid, network issue, operator error, name …

Often enough, it seems like you can begin working on software project with the assumption that you won't need to, say, design a little language and build a parser for it -- and yet, before long, that's exactly what you end up doing.

In the case of mod_ndb, my web services gateway for MySQL Cluster, the little language turns out to involve page-description -- it describes how to take a table of results from a database query and present it within an HTTP response. Inside an httpd.conf file, it looks something like this:

<OutputFormat XML> 
   Table  scan = '<NDBScan>\n$row$\n...\n</NDBScan>\n' 
   Row    row  = ' <NDBTuple> $attr$ \n  ...  </NDBTuple>'
   Record attr = '<Attr name=$name/Q$ value=$value/Qx$ />' or '<Attr name=$name/Q$ isNull="1" />'
</OutputFormat> 

<OutputFormat JSON> 
   Table  array  = '[\n …

Those of you who, like we do here at Pythian, have the pleasure of supporting both MySQL and Oracle environments (among others) will definitely know who Tom Kyte is. He is a VP of Oracle in the Public Sector group, but he’s much more well-known for his Ask Tom site, where he has been the [...]

By Allison Randal

In November of last year Microsoft and Novell announced a collaboration deal between the two companies. The exact terms of the deal haven't been released yet, so it's difficult to evaluate it in any substantial way. The two companies report that the deal involves some form of cooperative marketing, development in virtualization and interoperability, document format compatibility, and a patent agreement. It's that last item that has sparked all the controversy.

There's no question that the announcement could have been handled better. What is still an open question is whether the deal represents a threat to free software. We just won't know until we see the terms. (A recommendation for the future: releasing the full terms of the deal at …

MySQL Forge has been recently worked on. The Wiki got updated, there are some new extensions sitting around, and its “secure” as MediaWiki can get. The Forge itself has a nice little MySQL Conference & Expo banner, kudos to Lenz. Incidentally, register now, already. MediaWiki doesn’t have great banner support, so you’ve actually got to go in and hack on the PHP to display banners (MediaWiki:Sidebar itself, doesn’t support image loading! Then how do you link to an image?).

Been doing so much other stuff at MySQL recently, its a bit refershing to work on Forge. We’re safely off the 1.6 branch, and single sign on should be a goal next.

From the Google Summer of Code point of view, we’ve got a firmed up “wanting to …

On Saturday, 24th March ‘07, Open Source ?Unconference? was held at Mumbai, India.

It was great learning experience for everyone and a good event to network with MySQL users and developers in India. K. K. George, the project leader for open source Zmanda Recovery Manager for MySQL, gave a talk about MySQL backup and recovery. Zmanda Recovery Manager is Zmanda’s MySQL backup and recovery project that has become quite popular with MySQL administrators. It has scheduling, reporting and monitoring functionalities for MySQL databases. In addition, it can do incremental backups and can also parse the complex binary log files of MySQL dump. Remote MySQL server backup is also supported through SSH and socket options. There was lot of …

So, with a bunch of recent tests I added (and some bugs that have been fixed) we’re now consistently getting 203 or 204 passing tests. We’ve got typically around 8 or 9 that often fail - often because the test may be broken or not quite deterministic. Or there’s a bug… :)

(all numbers for the daily-basic list of tests for various 5.1 branches).

It would be great to hit 300 by this time next year… which means a lot of test cases… hrrm… anybody want to volunteer?

After much pain and suffering (One of the four noble truths!), trying to figure out how to get UnixODBC and various ODBC drivers to play nicely, I Have this to show:


mysql> show variables like 'port';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port | 3306 |
+---------------+-------+
1 row in set (0.06 sec)

mysql> create table mysqlodbc_test (id int(4), name varchar(32));
Query OK, 0 rows affected (0.05 sec)


And:


mysql> show variables like 'port';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port | 5555 |
+---------------+-------+
1 row in set (0.00 sec)

mysql> show storage engines;
…

I wrote an article late last week about benchmark results for the two table-synchronization algorithms I’ve been implementing for the MySQL Table Sync tool. I’ve spent some time developing a test suite for the tool, and learned some really interesting things about the general problem of synchronizing tables. Progress on MySQL Table Sync My test suite caught some great bugs, but not as many as I’d expected, which is a great feeling.