The latest from the MySQL community

The other day I had a case with an awful performance of a rather simple join. It was a join on tb1.vid = CONCAT('prefix-', tb2.id) with tb1.vid - indexed varchar(100) and tb2.id - int(11) column. No matter what I did - forced it to use key, forced a different join order, it did not want to use tb1.vid index for it. And no surprise it was way too slow, the number of rows analyzed was really huge:

PLAIN TEXT SQL:

1. mysql> EXPLAIN
2.     -> SELECT
3.     ->  tb1.*
4.     -> FROM tb2
5.     -> STRAIGHT_JOIN tb1
6.     -> WHERE
7.     -> (
8.     ->    tb1.vid LIKE 'prefix-%' AND
9.     ->    tb1.vid = CONCAT('prefix-', tb2.ID) AND
…

A good two weeks ago, MySQL 5.1.22 was released. MySQL 5.1 is a new release of MySQL Server, with new features like

• partitioning (likely the top feature in 5.1)
• events (”crontab” triggers in the database)
• row-based replication
• table logs
• some XML functions

and also with major bug fixes, such as the AUTO_INCREMENT table-lock contention in InnoDB (fixed now in 5.1.22), as well as early indications of performance improvements of up to 20 % - 40 % on dual cores in some scenarios.

Jay Pipes has written an overview that compresses all of the pointers to 5.1 into one article, …

Sun recently announced the Sun SPARC Enterprise T5120 and T5220 and Sun Blade T6320 systems based on the UltraSPARC T2 processor.  You can find lots of information on the various features and functionality provided by these servers.

One other cool feature is that these systems ship with Cool Stack pre-loaded. The Cool Stack 1.1 packages are available in /var/spool/pkg. You can install the ones you want using the pkgadd(1M) command as follows :

root@wgs40-82 # cd /var/spool/pkg
root@wgs40-82 # ls
CSKampSrc_sparc.pkg        CSKphplibs_sparc.pkg
CSKamp_sparc.pkg           …

Just noticed in my inbox this morning a piece of email with the
following URL:
http://developer.amazonwebservices.com/connect/ann.jspa?annID=241

So it looks like the days of having to "know someone" to get an EC2
account is now over. It is also nice to see that 64bit instances are
now available.

Last week when I was at the PHP Zend conference talking about how to
deploy MySQL in EC2 and I got several questions that boiled down to
"but can I get a bigger instance"?

Which my answer was "I'm sure that is what they are thinking of
doing", when the real answer could have been "look closely at my
running configuration and you will notice what my instance is".

It is good to see Amazon make the announcement, especially after last
…

In this post I will try to explain how memory management works inside MySQL Cluster.
Memory management differs between different versions of MySQL Cluster.

The general idea is as follows:

• Data (and ordered indexes) is stored in the DataMemory section. The DataMemory is organized in pages where each page is 32KB.
• You can view the DataMemory as a pool of pages consisting of X number of 32 KB pages.
  
• A table is associated with one or more pages from the DataMemory (pool of pages) depending on how much data is stored in the table.
  

That is the general stuff, now let's see how this is used.

5.0 and 5.1

Allocation

1. If the table is empty and there is an insert - one page will be allocated from the page pool (DataMemory) and associated with that table.
   
2. Subsequent inserts will fill up the data …

Sun recently announced the Sun SPARC Enterprise T5120 and T5220 and Sun Blade T6320 systems based on the UltraSPARC T2 processor.  You can find lots of information on the various features and functionality provided by these servers.

One other cool feature is that these systems ship with Cool Stack pre-loaded. The Cool Stack 1.1 packages are available in /var/spool/pkg. You can install the ones you want using the pkgadd(1M) command as follows :

root@wgs40-82 # cd /var/spool/pkg
root@wgs40-82 # ls
CSKampSrc_sparc.pkg        CSKphplibs_sparc.pkg
CSKamp_sparc.pkg           …

Sun recently announced the Sun SPARC Enterprise T5120 and T5220 and Sun Blade T6320 systems based on the UltraSPARC T2 processor.  You can find lots of information on the various features and functionality provided by these servers.

One other cool feature is that these systems ship with Cool Stack pre-loaded. The Cool Stack 1.1 packages are available in /var/spool/pkg. You can install the ones you want using the pkgadd(1M) command as follows :

root@wgs40-82 # cd /var/spool/pkg
root@wgs40-82 # ls
CSKampSrc_sparc.pkg        CSKphplibs_sparc.pkg
CSKamp_sparc.pkg           …