In an attempt to better understand the WebDAV standards space, I made up a non-scientific graph of all the specs and dependencies. I'd like to get started with CalDAV, but I have a few other specs to implement before I'll be able to do that.

The next one for me on the list is ACL. Attempting to integrate these new features within the existing system so far has proven to be very challenging. The big reason is my (perhaps high) requirements on how this is supposed to work:

• It shouldn't touch the existing WebDAV system (at all), because 99% of the users will not use ACL.
• The interface & implementation should still be understandable if you are implementing ACL.
• I like the existing WebDAV class structure as it stands, so if I have to make changes in the design; it should still be easy to grasp.

A comment to the last article:

"I had trouble implementing something like this using mysql-proxy + lua. Basically I wanted a way to force the developers, when using dev systems by console, every query they execute also follow up with an EXPLAIN. The exact mechanics of it I still need to work out, but having an explain run after testing a query I thought would be a great idea, or at least, if lua could detect a table scan and flag it as a warning or similar. One day I hope to give it another try." — Bradley Falzon

Just check the current mysql-shell branch on launchpad.net.

Here's what the script in the background does:

• execute the query
• get warnings, if there are any
• execute SHOW STATUS
• if this was a table-scan and a Com_select, run EXPLAIN …

Grab your calendars and mark the following dates :

• T-Dose 2009 will be held on 3 and 4 october in Eindhoven again.

  Last year we had a nice Drupal track, some great MySQL talks and , a great unplanned Cloud talk , and different other interesting talks, so this year promises also to be very interesting.
  (PS. Drupal Themers.. you might want to propose a new theme for the T-Dose site, who knows you'll even win something)

• For the first time , 2009 will be the year that Belgium will have it's own Security Conference, BruCon has just announced Christofer Hoff as a KeyNote speaker , BruCon will take place on 18 and 19 september... obviously in Brussels ;)
• While we mention VirtSec …

bencher is a test program that allows you to benchmark requests on MySQL Cluster. I have used this utility a lot of customers, because it lets me:

• specify a simple query that I want to benchmark on the command line
  
• implement more complex use cases.
  
• implement NDBAPI requests

and I don't have to reinvent the wheel every time. It is all there: connectivity, multi-threading support, timers, and some basic statistics, and it compiles on most platforms. I just have to focus on the queries I want to optimize or benchmark.

The simple use case is to specify the SQL query you want to benchmark, the number of threads, and how many times. You can also customize this very easily to benchmark more elaborate SQL requsts, and NDBAPI requests.

…

MySQL University keeps rolling along. We’ve had some fantastic sessions just recently (not including my own, of course!), such as Lenz’s presentation of backing up MySQL with filesystem snapshots, Allan Packer’s presentation on the optimization of MySQL and, going back a little further, David Van Couvering and Petr Pisl’s talk on using PHP and MySQL within Netbeans.

Remember that all of these presentations can be viewed again online if you missed them first time round!

We’ve got some good topics coming up, but we ned more!!

Got some hot topic that you want to tell the world about?

Using MySQL in an interesting way?

Got a good MySQL scalability story that you want to tell?

Developed a great storage engine?

Any and all of these topics are welcome for discussion and presentation at MySQL University.

Last weekend I started a shell that is based on the core libs of the MySQL Proxy and now code is good enough to be really useful.

As the shell is internally driven with a lua-script it is very easy to change the display or the way how the result of a query is processed. A simple feature that comes to mind is appending a SHOW WARNINGSwhenever query resulted in warning.

root@127.0.0.1:3306 []> create table t2 ( id serial ) engine = foo;
OK (warnings: 2, auto-commit: true, affected rows: 0, insert-id: 0)
+---------+------+--------------------------------------------+
|  Level  | Code |                  Message                   |
+---------+------+--------------------------------------------+
| Warning | 1286 | Unknown table engine 'foo'                 |
| Warning | 1266 | Using storage engine MyISAM for table 't2' |
+---------+------+--------------------------------------------+
OK (warnings: 0, auto-commit: true)

Following scenario... you want to pass on some basic info to another task, through MySQL, and the other task can just wait for it - naturally you don't want to poll (keep issuing a query to see if there's anything new) as that's hideously inefficient even if you use the query cache.

Rules: standard MySQL (no special storage engines); and stay within MySQL, no other tools.

I have some thoughts on this, for instance using the behaviour of InnoDB with isolation levels and locking... can be engineered to either acquire a lock (after waiting for someone else to release) or timeout, where the timeout can be set so you don't have to poll all the time... but curious if anyone might have more nifty ideas!

A couple interesting things coming out of startup land.

For one, Posterous has a little writeup on Building and Scaling a Startup on Rails: 12 Things We Learned the Hard Way. Good things to take away include using Sphinx/Solr for search, but the real important takeaway for the MySQL crowd is Storage engine matters, and you should probably use InnoDB. If you’re writing an application, know your storage engines. There are also bits to tell you how to use query_viewer and New Relic to help you fix database bottlenecks, use memcached later, and more. Its a great read.

Next up, there’s How FriendFeed uses MySQL to store schema-less data. I hope Bret from FriendFeed writes more on their infrastructure over …

During development cycle, I often come to a case where I need to compare two tables whether they are the same or not. For example, if you already have a running script that outputs to a database table in production that was written sub-optimally and you need to improve it. You want to make sure […]

When I visit customers quite often they tell me about number of creative techniques they heard on the conferences, read on the blogs, forums and Internet articles and they ask me if they should use them. My advice is frequently - do not. It is fun to be creative but creative solutions also means unproven and people who had to become creative with their system often did that because they had no choice. Of course when they came to the bunch of conferences and told their story which resonated across the Internet sticking to the people mind as a good practice.

There are 2 things you should ask yourself. First is the scale comparable - the recipes from Facebook, YouTube, Yahoo, are not good for like 99.9% of the applications because they are not even remotely close in size and so capacity requirements. Second if this "smart thing" was truly thought out architecture choice in beginning or it was the choice within code base …