Over at the Drizzle blog, the recent 2010-06-07 tarball was announced. This tarball release has my fixes for the ENUM type, so that it now works as it should. I was quite amazed that such a small block of code could have so many bugs! One of the most interesting was the documented limit we inherited from MySQL (see the MySQL Docs on ENUM) of a maximum of 65,535 elements for an ENUM column.

This all started out from a quite innocent comment of Jay‘s in a code review for adding support for the ENUM data type to the embedded_innodb engine. It was all pretty innocent… saying that I should use a constant instead of the magic 0×10000 number as a limit …

So William was asking on twitter how to best deploy symfony apps to a cluster of servers. There are actually some nice deployment tools inside the symfony cli that ease deployment to a single server, but that doesn't really cover the cluster case. Actually I assume that if you have a cluster of servers the best deployment strategy should probably be optimized against your specific use case. But let's make this question a bit more general: How do you deploy updates to your PHP apps running a clustered setup? What architecture do you pick? How do you keep the site running with as few limitations as possible during the update? How do you distribute the new code? How do you clean and prime your caches? How do you handle DB changes? How do you ensure that the DB and code changes do not get in the way of each other?

Obviously the choice of RDBMS can play a big role …

I have blogged about prepared statements a few times, which is what most people rely on (too much) for SQL injection protection. I say too much because they do not really protect code fully against SQL injection attacks and they come with a lot of performance hurting baggage. To sum up: prepared statements do not handle all aspects of dynamic SQL creation, they add network I/O and memory overhead and they tend to generate less optimal query plans. Some of these issues can be solved by doing client side emulation, but that brings with itself its share of issues and I have to agree with Bill and not Brian that …

Install and Run Apache Roller 4.01 on GlassFish and OpenSolaris
Dave Koelmeyer has posted Detailed Instructions on how to install Apache Roller 4.01 on GlassFish v2.1 using MySQL 5.1 for storage.  He uses OpenSolaris snv_134, the subject of a tea-leaf-reading thread.

Slides and Code Samples on Jersey and JAX-RS
The Slides and code from Paul Sandoz's presentation at Presentation at AlpesJug on Jersey, JAX-RS and Atmosphere are now  …

http://drizzle.org/wiki/Drizzle_Developer_Day_2010

Upstairs in the Hyatt right near the Speaker room (down the hallway on the left from the main conference registration desk).

See you here!

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One of the key features of NoSQL is the fact that its schema-less. Awesome. Of course I could just dump a serialized string of my "document" into an RDBMS and I could end up with more or less the same, but the big difference of course is that NoSQL (to me key-value stores do not fall under the NoSQL umbrella) still supports non hacky ways to interact with individual values inside a document as well as indexing. But while at first it might seem great to not have at the database enforce a specific schema, the app developer better have a good idea of his schema. Otherwise one developer might call a field "is_active" the next one might call it "isActive" and another one "enabled". I have little to no experience with CouchDB, MongoDB etc. but I am not really all that thrilled about schema-less for the above reason, what I want is no-cost-for-schema-changes, I do want a schema!

This is why I was quite thrilled back when IBM come out with top …

Here’s something that’s not really documented anywhere (unless you count ha_innodb.cc as a source of server documentation). You may have some idea about the MySQL/Drizzle row buffer format. This is passed around the storage engine interface: in for write_row and update_row and out for the various scan and index read methods.

If you want to see the docs for it that exist in the code, check out store_key_val_for_row in ha_innodb.cc.

However, there is another format that is passed to your engine (and that your engine is expected to understand) and for lack of a better name, I’m going to call it the key tuple format. The first place you’ll probably see this is when implementing the index_read function for a Cursor (or handler in MySQL speak).

You get two things: a pointer to the buffer and the length of the buffer. Since a key can be made up of multiple parts, some of which can be NULL and some of which can be of …

So everyone is blogging about NoSQL like there was just a divine intervention that handed us this epiphany just 2 weeks ago. Well I guess the term has still sort of fresh so everybody is busy making sure Google, Bing and friends get at least one hit on their blog when people search for NoSQL. Now is my turn.

A lot of the following is stating the obvious (though a lot of NoSQL posts from either side of the fence - why is there even a fence on this topic? - are not mentioning them .. so maybe not so obvious:

• use the right tool for the job (yes I still have use cases for MyISAM)
• NoSQL is a sucky name, because while some people also hate SQL, the key change is in dropping the relational model and/or ACID
• So yes you can take away the SQL interface from a MySQL storage engine and its still not what people think of when they say NoSQL
• You could stick an SQL interface in front of a NoSQL …

Most software people are aware of the ACID acronym coined by Jim Gray. With the growth of the web and open source, the scaling and complexity constraints imposed on DBMS implementations supporting ACID are more visible, and new (or at least new terms for known) compromises and tradeoffs are being discussed widely. The better known NoSQL systems are giving insight by example into particular choices of tradeoffs.

Working at MySQL, I have often been surprised at the variety of potential alternatives when implementing a DBMS, and the number of applications which don't need the full set of ACID letters in the strictest form. The original MySQL storage engine, MyISAM is one of the first and most successful examples of an 'ACID remix'. The people …

Ages ago I created a Twitter account to get some free app. I figured some nobody was following me I didn't have to feel like a guilty spammer. For some odd obsession to honesty probably I did use my proper name and sooner or later people started following me despite me having only put out a single spam message. So on very few occasions I tried out tweeting (still feels weird using that word) since then, obviously I have never used it to get a free app again by spamming. Anyways I have now decided that for small blurps about technical stuff I will from now on use Twitter, thereby sparing my Facebook friends from such gibberish. In turn my developer friends on Facebook that do not care about what I have to say about Frisbee, DJing or politics can start removing me from Facebook. Actually I might just do this myself, because its FUCKING ANNOYING that so many people multi spam their status …