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LogFile Group creation - SQL Errors vs SQL Warnings

On Windows® - but I guess it’s the same on another O.S. that does not support cluster - I noticed the following behavior when trying to execute a CREATE LOGFILE GROUP syntax like this:

CREATE
 LOGFILE GROUP `test`
 ADD UNDOFILE ‘test’
 INITIAL_SIZE = 33M
 UNDO_BUFFER_SIZE = 8M
 ENGINE = NDBCLUSTER;

In v.5.1.25-rc, v.5.1.24-rc and v.5.1.23-rc, only SQL warnings are shown:

mysql> CREATE
    ->  LOGFILE GROUP `test`
    ->  ADD UNDOFILE ‘test’
    ->  INITIAL_SIZE = 33M
    ->  UNDO_BUFFER_SIZE = 8M
    ->  ENGINE = NDBCLUSTER;
Query OK, 0 rows affected, 2 warnings (0.01 sec)

mysql> SHOW WARNINGS;
…

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Which Database to Choose When Looking For a Job

I had a talk with a friend of mine, yesterday. He recommended to me that I should move away from MySQL and become more proficient with Oracle or MS SQL. The reason for this is that he argues that there is a higher chance I can find a job working in a company that uses a commercial databases (and also higher paid position) then I could for a company that uses an open-source database.

His logic was that:
If a company is already paying for a commercial database, they would have no problem paying some more for someone to maintain it or develop on it.
I started thinking about what he said to see if its true. Not so long ago, I worked on a project for big car manufacturer in China and they used Oracle databases. They had the resources to hire quite a few PL/SQL developers for something relatively simple (but I am pretty sure those PL/SQL developers are still working on it as they get paid by the hour).

On the …

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Lua: Using LPEG for SQL Indenting

I have a somewhat strange relation to parser since a while. Like everyone I started with writing little parsers by hand and bounced several times against yacc and flex failing to get around their very own syntax.

Then I discovered lemon and used it in lighttpd for the configuration and HTTP parsing, finally a parser syntax I could read. But it still was a split between lexing and parsing.

Along the the way there was ragel with its wonderful dot-output to visualize its state-engine, very neat and a mixed lexer and parser.

2-3 weeks ago I finally stumbled over LPEG and I'm happily writing parsers now. Like a simple one that can parse complex SELECT queries and …

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mysqlsla v2.00 released

mysqlsla v2 is finally “done” and released. About 3 months ago, when v1.8 was released, I said it would be coming “soon,” but time just flew by and here we are. Oh well. In any case, the v1 branch is dead to me and v2 is all the rave (at least for me). If you don’t care about the differences and all you want is your default top 10 report from a slow log, for example, then all you need to know is: mysqlsla -lt slow SLOW_LOG

For those interested in what has changed to warrant a new major version number, here’s the briefing of changes/overhauls:

  1. Almost ALL new command line options (–log-type a.k.a. -lt is the most important); see the documentation
  2. Customizable reports. In v1 the report was hard-coded. Now with -rf FILE you can format your own report. See the …
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The Project That Bit Back

Last November, I wrote an article describing an idea I had for a game/website.
Here is a short recap:

I wanted to make a web-based text game called Shadow People. Shadow people will be a game to do with government agencies and spy organizations.
There will be two different groups of agencies: Government owned/regulated ones and Terrorists/Freelance ones.
If it helps you imagining how it will look like, if anyone saw the series “"La Femme Nikita" with the actress Peta Wilson.
The game revolves round the cool and secret world of small yet highly effective organizations that either try to keep order in the world or cause chaos.
These organizations have the highest skilled personal, best equipment possible and will stop at nothing till they get what they came for.
Since then, I've been.. well.. busy …

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Do you store credit cards in your MySQL Database?

The Payment Card Industry Data Security Standard (PCI DSS) has been developed to help organizations that process card payments to prevent credit card fraud, cracking and various other security vulnerabilities and threats.

Performance of JOIN using columns of different numeric types

I know it's been a very long time since I posted anything, but I felt the itch today. A question came up earlier this week at work: How much is JOIN performance affected when using columns that are not the exact same data type?

This is important for me because entity-attribute-value tables require a lot of self-joins. Let me start by saying that we mitigate one of the common drawbacks to EAVs - mashing diverse data types into a single column - by separating numeric, date, and character data into different tables. However, we mashed a lot of integer data into a DECIMAL(13,4) column right alongside our financial data. I recently noticed that most of the data in this EAV table has no fractional part, and to determine whether it would be worth moving it all into another table - as well as determine what column type to use - I spent an afternoon running …

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MySQL Tidbits: The XOR Toggle

A web app full of data is often going to be full of tables (at least on the administration end). A listing of users here, all the recently created events there. Often for readability we will alternate rows between two slightly different background colors.This can be handled on the PHP end with a bit of math and a counter, like so:$count = 0;while( $row = mysql_fetch_assoc($res) ) {    if( $count % 2 == 0 )         $background_color = 'white';    else        $background_color = 'gray';    /* OUTPUT TABLE CONTENTS WITH GIVEN BACKGROUND */    $count++;}However, it can also be done entirely in-database, via creative use of the XOR operator: ...

Log Buffer #105, a Carnival of the Vanities for DBAs

This week, database blogs seemed to talk about conforming to stereotypes as well as breaking them.

Fulfilling the stereotype of Microsoft software being unsecure, Microsoft released a very important SQL Server update that Aaron Bertrand notes patches “four elevation of privilege vulnerabilities.” That’s right, not one, not two, but four!!! At least there is a patch now……go forth and patch! Usually it is MySQL that throws ambiguous warnings or errors which are not an accurate representation of the actual error, but Bertrand also notes that there is A Little Management Studio Oops.

Contrary to stereotype, …

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Discovering FALCON Metadata in MySQL® v. 6.0.5-alpha

Introduction
MySQL® 6.0.5-alpha, the latest version of the 6.x branch of the Database Server, is available for download from the SUN|MySQL Web Site.

Metadata (data about the data) are very important, especially for software developers. In this article we will see what’s new in FALCON metadata handling doing some comparison with the old 6.0.4-alpha version.

New tables in the `information_schema` database
As you know, the source for metadata is the database `information_schema`. To start, let’s see which tables related with FALCON metadata are included in that database:

mysql> SELECT VERSION();
+—————————+
| VERSION()                             |
…

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