I spoke at EdUIConf 2009, a new conference in my hometown of Charlottesville, Virginia. My presentation was on web interface performance; it's basically a twist on front-end performance in general. I slanted the talk towards web developers, rather than assuming the audience has full control over their Apache configuration.

The conference was relatively short -- two days. The first day was full-day sessions. I skipped from Molly's session on emerging web standards (good; summary of what I witnessed: HTML5 cometh) to Dan's session on visual design, which was excellent. The second day I wasn't able to make it for the morning, and …

There is no centralized authentication for mysql. You have to set up your user accounts individually for each of your mysql servers. You can use replication, but that would mean, your master servers must have the same authentication privileges as your slaves have. What about security?

So, here is a little workaround that I did and I can't find the same anywhere.

How does it work?

This is an unofficial and unsupported solution. Let's have a master and one or more slave hosts. On your master, you have to create a database lets say slave_auth. Create the same tables in this database as you have in the 'mysql' database and needed for authentication (more details below), and set up a user who can read/write those tables.

When you are done, create a temporary database on your slaves lets say auth_temp with the exact structure of the tables on your master, but with federated engine connected to your …

This entry is a follow up to TOTD #95 and shows how to use the recent integrations of JSR 299 in GlassFish v3 to convert a JSF managed bean to a JSR 299 bean (aka Web Beans). The TOTD #95 describes a simple Java EE 6 web application that uses Java Server Faces 2.0 components for displaying the results of a database query conducted by EJB 3.1 and JPA 2.0 classes.

The EJB class, which …

This entry is a follow up to TOTD #95 and shows how to use the recent integrations of JSR 299 in GlassFish v3 to convert a JSF managed bean to a JSR 299 bean (aka Web Beans). The TOTD #95 describes a simple Java EE 6 web application that uses Java Server Faces 2.0 components for displaying the results of a database query conducted by EJB 3.1 and JPA 2.0 classes.

The EJB class, which …

Innodb monitors show information about innodb internal status - which could be used for performance tuning. Lets break down the output of show engine innodb status and get a look at what is happening and how it can be improved. Just fire the "Show engine innodb status" command and check the Output.mysql> show engine innodb status\G*************************** 1. row ***************************

Recently a colleague at Sun was asking me if MySQL can tell him to determine if we are currently in summer time or winter time. He was doing some data analysis of his house where he has installed solar panels.

I am not aware of what he wants to do exactly, but possibly he wants all the data in solar time. So UTC could help him because UTC does not change much over time.

Next thing which came to my mind is, that possibly the good place to do such math calculations is the application code and not the database.

But never the less I was interested in how to solve this IN the database.

By default your MySQL server relies on your servers time zone. [1]

So if your server is set-up correctly you should be capable to determine if you are in summer time or winter time by your current time, UTC time and the offset you have to UTC.

mysql> SELECT IF(ROUND(TIME_TO_SEC(SUBTIME(TIME(SYSDATE()), …

If you need to create a big database into MySQL Cluster with:

• A lot of tables indexes, columns, and tables
• A lot of records
  

there are a few things to think about:

• If a table has > ~90M records, you have to create the table with MAX_ROWS=<amount of records in table anticipating growth>:
  CREATE TABLE t1(...) ENGINE=ndbcluster MAX_ROWS=200000000;
  This way the data node will allocate more partitions for the table, since there is a limitation in how many records that can be stored in one partition (and the limit is around 90M records).
  
• Many tables / table objects --> Make sure you increase MaxNoOfTables (kernel limit is 20320 tables). This creates a table object pool of size MaxNoOfTables.
  
  • Each table you create will use one table object. …

Recently a colleague at Sun was asking me if MySQL can tell him to determine if we are currently in summer time or winter time. He was doing some data analysis of his house where he has installed solar panels.

I am not aware of what he wants to do exactly, but possibly he wants all the data in solar time. So UTC could help him because UTC does not change much over time.

Next thing which came to my mind is, that possibly the good place to do such math calculations is the application code and not the database.

But never the less I was interested in how to solve this IN the database.

By default your MySQL server relies on your servers time zone. [1]

So if your server is set-up correctly you should be capable to determine if you are in summer time or winter time by your current time, UTC time and the offset you have to UTC.
mysql> SELECT …

A very wise systems programmer once told me: “Don’t guess. Measure.” Since then, I’ve learned the hard way that guessing too much about performance is death by a thousand cuts. For RethinkDB, dozens of factors for I/O alone affect performance (not to mention memory, buses, caches, and CPU cores). In order to design the fastest database on Earth, we constantly test the following factors:

• Performance of read and write operations.
• Behavior for random and sequential workloads:
  • For random workloads, the behavior of uniform, normal, and power distributions (with different distribution parameters).
  • For sequential workloads, the seek direction and various strides .
…

The favourite Open Query course modules as well as reworked and brand new ones, with November/December 2009 dates for Brisbane, Sydney, Canberra and Melbourne listed below. You can register for days/modules individually, to suit your time, budget and current needs. Your trainers are Sean, Ray and Arjen (see OQ people).

For the Canberra and Melbourne days which are DBA/HA, registrations for all of the modules in a series before 15 October will receive a copy of the “High Performance MySQL” book (normal bookstore price is AUD 105).

Canberra

• Thu 5 Nov: MySQL High Availability – Strategy and Tools
• Fri 6 Nov: MySQL Cluster …