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Displaying posts with tag: General (reset)
Drizzle Developer Day is TODAY!

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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Gimme a schema for the schema-less

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 …

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The Drizzle (and MySQL) Key tuple format

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 …

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Obligatory NoSQL post

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 …
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ACID tradeoffs, modularity, plugins, Drizzle

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 …

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Twitter vs. Facebook

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 …

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Kontrollsoft’s uptime checks now managed by Pingdom

Website health checks are a crucial service to an operations team. In addition to in-house monitoring and service state reporting it’s also important, even critical, to have an impartial third party to run checks to test your customer facing services. There are a lot of companies in this arean that would be glad to have [...]

Writing A Storage Engine for Drizzle, Part 2: CREATE TABLE

The DDL code paths for Drizzle are increasingly different from MySQL. For example, the embedded_innodb StorageEngine CREATE TABLE code path is completely different than what it would have to be for MySQL. This is because of a number of reasons, the primary one being that Drizzle uses a protobuf message to describe the table format instead of several data structures and a FRM file.

We are pretty close to having the table protobuf message format being final (there’s a few bits left to clean up, but expect them done Real Soon Now (TM)). You can see the definition (which is pretty simple to follow) in drizzled/message/table.proto. Also check out my series of blog posts on the table message

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Ash Wednesday:Repent, and believe the Gospel and MySQL

It’s Ash Wednesday today (Feb 17th 2010) !! I learnt that Ash Wednesday derives its name from the practice of placing ashes as a Sign of the Cross on the…

The post Ash Wednesday:Repent, and believe the Gospel and MySQL first appeared on Change Is Inevitable.

TOTD #122: Creating a JPA Persistence Unit using NetBeans 6.8

Taking TOTD #121 forward, this blog explains how to create a JPA Persistence Unit for a MySQL sample database and package it as a library. This JAR file can then be easily included in other web applications.

Lets get started!

  1. Configure GlassFish for using the MySQL sample database (sakila) as described in TOTD #121.
  2. Add the GlassFish instance in NetBeans IDE using "Services" panel.
  3. Create JPA entities using NetBeans IDE.
    1. Create a Java class library:



      Our ultimate goal is …
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