About year ago Peter wrote about redundant indexes and mentioned sometimes it is good to leave two indexes, even one is first part of another. I'm speaking about BTREE indexes, for example, KEY (A), and KEY (A,B). From SQL point of view KEY(A) is not needed, as for queries like WHERE A=5 the index (A,B) also can be used.

But there is case when for performance it would be good to have both

Let we have the table

PLAIN TEXT SQL:

1. CREATE TABLE `userinfo` (
2.   `id` int(10) UNSIGNED NOT NULL AUTO_INCREMENT,
3.   `name` varchar(64) NOT NULL DEFAULT '',
4.   `email` varchar(64) NOT NULL DEFAULT '',
5.   `password` varchar(64) NOT NULL DEFAULT '',
6.   `dob` date DEFAULT NULL,
7.   `address` …

ActiveGrid, Inc., a leading provider of Enterprise Web 2.0 solutions, has announced it is working with MySQL to simplify the migration of legacy applications to modern web architectures. Last week, the companies published the "Microsoft Access to MySQL Migration Guide," a quick guide to migrating MS Access applications to a CIO Safe, Enterprise Web 2.0 deployment architecture. Next month, the two companies will be offering a free webinar covering Application Migration to Enterprise Web 2.0.

When I started, I found the section on backups in the manual a bit confusing. I wanted to know, what’s available for InnoDB backups that would correspond to “exports” and “hot backups” for Oracle. I had trouble extracting a clear answer from the manual.

Here’s what I’ve found over time, to the best of my knowledge.

Assuming you don’t want to buy extra software (eg, Zmanda), you can use mysqldump (”export”) and/or LVM (”hot backup”) for your backup needs. (mysqlhotcopy is not for InnoDB.) Replication is nice, too. Here’s a bit about each method.

1. mysqldump (think “export”)
You can get a full backup, even for point-in-time recovery, using mysqldump. Mysqldump is sort of like Oracle’s export. Dumps the database, and you can use it to import it back. It creates a bunch of text commands that you can redirect into a mysql client to do the import. And mysql has a tool for …

In the Enterprise Team we had the need to track how many connections to the MySQL server in parallel. By "used" I mean running queries and not just idling around.

And to make it more complicated we needed the information not just every few seconds (while true; do echo "SHOW PROCESSLIST" | mysql; sleep 1;done) but when it happens.

Proxy to the rescue we now have a script which tracks the global state of all connections going through the proxy and dump them to stdout when their state changes:

2007-08-28 21:39:55
  #connections: 20, #active trx: 3, max(active trx): 4
  [792] (merlin@merlin) (COM_QUERY) "SET autocommit=0" (state=started)
  [794] (merlin@merlin) (COM_QUERY) "SET autocommit=1" (state=started)
  [795] (merlin@merlin) (COM_QUERY) "SET autocommit=1" (state=started)

• when the query comes in, we add it with its thread-id to the global table
• when the query is done, we track …

On Friday I committed code to 3.0 trunk to allow people to execute an MDX query on a Mondrian server and get the result back in a tabular format. This particular code to “flatten” an OLAP cube into rows was written by Julian Hyde, the lead developer and founder of Mondrian OLAP a.k.a. Pentaho analyses.

If you run the Pentaho demo on your box and then look at the Analyses sample, you could see something like this:

Suppose you wanted to get this exact data to work with, create analytical data, exports, … Well, now you have the option of doing it in Kettle:

What you do is create a database connection to the database that Mondrian reads from, hand it the location of the Mondrian schema (catalog). You then click on the MDX button in JPivot and copy the MDX query to the “Mondrian Input” step in Kettle. That’s all it takes.

You then can preview …

Solid has released 5.0.45-0077. New features include full support for prefix indexes and support for multiple NULLs on unique indexes. This release also has a number of bug fixes. For the full detailed list of bug fixes and enhancements, please see the ChangeLog. Check it out at http://dev.soliddb.com/download

First of all, I'd like to start my first blog entry with a special thanks to Edwin De Souza from MySQL. I would not be blogging if it wasn't for his kind advice. Thanks!

Now to the subject in question. It seems like the word "enterprise" is now just a marketing term that really means nothing and its added freely to all sorts of software. Since we emphasize jbilling as an enterprise billing system, I'd like to clarify my understanding of what enterprise means, at least to me.

Common associations with the term are "large", "for businesses" or even "serious". Indeed, an enterprise application could be (and commonly is) all of the above. But it doesn't have to be. The software that runs the avionics of a plane can be very serious and very complex. Yet, it is not an enterprise application.

So, you can write very important, very complex and very advance software and still not be writing enterprise software. Enterprise …

First of all, I'd like to start my first blog entry with a special thanks to Edwin De Souza from MySQL. I would not be blogging if it wasn't for his kind advice. Thanks!

Now to the subject in question. It seems like the word "enterprise" is now just a marketing term that really means nothing and its added freely to all sorts of software. Since we emphasize jbilling as an enterprise billing system, I'd like to clarify my understanding of what enterprise means, at least to me.

Common associations with the term are "large", "for businesses" or even "serious". Indeed, an enterprise application could be (and commonly is) all of the above. But it doesn't have to be. The software that runs the avionics of a plane can be very serious and very complex. Yet, it is not an enterprise application.

So, you can write very important, very complex and very advance software and still not be writing enterprise software. Enterprise …

Today, Hi-Media (HIM.PA), a French publicly traded company, has announced that it is acquiring Fotolog (my employer) for approximately $90 million in a 23% cash and 77% stock transaction.

Hi-Media was founded in 1996 and currently the Hi-Media Network is the French leader in interactive marketing and the third largest in Europe.

Last year, in April, we had 3 million members and 100 million photos. Today, the number is more than 10.5 million. We are also very close to reaching 300 million photos.

" …

I started work on a Java class that mimics the functionality of the mysqldump command today.
My goal is to create a standalone application to begin with, but design the class such that it can be plugged into any other Java application requiring MySQL backup capability.

After completing the initial prototype of the dump_table method (minus blob support), I began to wonder what the performance would be like compared to the bundled mysqldump application (written in C).

As this was a prototype with no optimisations, the results were not that bad. The following figures were obtained from running both the C-based mysqldump and the MySQLDump.java app against a fairly large innodb …