A Materialised View (MV) is the precalculated (materialised) result of a query. Unlike a simple VIEW the result of a Materialised View is stored somewhere, generally in a table. Materialised Views are used when immediate response is needed and the query where the Materialised View bases on would take to long to produce a result. Materialised Views have to be refreshed once in a while. It depends on the requirements how often a Materialised View is refreshed and how actual its content is. Basically a Materialised View can be refreshed immediately or deferred, it can be refreshed fully or to a certain point in time. MySQL does not provide Materialised Views by itself. But it is easy to build Materialised Views yourself.
I've done a multitude of benchmarks using various 2.6 IO
schedulers. Hands down the Deadline I/O scheduler is the best for
INNODB traffic or RANDOM IO. I use to have all this benchmark
information in excel worksheets, but lost it when I left
Friendster.
Here is how to figure out what IO scheduler your using in Linux
2.6
dmesg |grep -i sched
In most cases your probibly set up to use the cfq io scheduler.
Change it to deadline in your PXE, lilo, or grub settings.
For example:
# For booting GNU/Hurd
title GNU/Hurd
root (hd0,0)
kernel /boot/gnumach.gz root=hd0s1
module /boot/serverboot.gz
append to it
kernel /boot/wtfe root=wtfe elevator=deadline
Thanks Peter N. for the linux config info!
Since Oracle announced their fork of Red Hat Linux most of the news coverage has been about the business implications for Red Hat and other Linux vendors. To be honest, I don't think the impact is all that significant. Decisions are made by one guy at Oracle (much to the chagrin of many of his executives) and if Larry decides he wants to fork with Red Hat, then he tells his guys to get it done. So what do they do? They post CentOS for download on the Oracle web site and call it their own. And as part of that, Oracle is now distributing MySQL, which is ironic, but nonetheless appreciated.
Maybe Oracle customers think that Oracle can do a better job supporting their OS than the guys who wrote …
[Read more]We’ve been saying here and elsewhere that the Microsoft-Novell and Oracle-Red Hat announcements have been market changing events. Some ripples are at the fore: Microsoft has siezed an opportunity to simultaneously head off Oracle and irritate Red Hat. Novell has turned its greatest weakness (the spectre of irrelevancy as recently as last week) into what could prove to be a great strength (It’s a little creepy in its Karl-Rove-esqueness, actually).
And Red Hat itself now faces the real possibility of extinction … Overnight, Red Hat has become the flattest piece of land between two battling superpowers: the Poland of software vendors.
Less obvious is the effect on Ubuntu’s plans to burst onto the enterprise scene in the West. Ubuntu’s sponsor, Canonical’s, overriding strategy hinges on two key pillars. First, Ubuntu is feature-rich and easy-to-use, to appeal to non-fuddy-duddys - that next generation of young …
[Read more]
Friday the 3th of November I presented my work at the University
of Twente to my fellow students and my supervisors. The slides of
this presentation are available through this link:
Presentation at University of Twente, 3th of
November 2006
All students and supervisors present that day are encouraged to
post their comments.
Blog: http://sqlbusrt.blogspot.com/
Project website: http://sqlbusrt.sourceforge.net/
Tim has written another insightful piece on where technology is going, based on the technology books people are buying.
With this in mind, take a look at the tree map for programming languages. (Keep in mind, as Tim notes, that "the size of a square indicates the relative size of the category, and its color indicates the rate of change. A category that is bright green is up significantly. One that is bright red is heading strongly in the other direction.")
What are the takeaways?
-
Ruby has continued to grow apace, although its 255% growth rate is off last quarter's torrid 687% increase! Interestingly, PHP also picked up some steam, up 11% vs. last quarter's 6% YoY increase. Python's 27% YoY gain, up from last quarter's 6% gain, shows even more strength. In short, while Ruby has become the …
Released a new version of the procedure converter from SQL Server
to MySQL. The changes are driven by user requests.
I have added support for temporary table creation: in SQL server
you create a temporary table by adding INTO #temptable to your
select. This is converted to MySQL CREATE TEMPORARY TABLE and the
# is dropped.
Also some minor changes, like support for very large SQL
statements, better pretty-printing and improved support for CASE
statements.
By Tim O'Reilly
Last week, I talked about the overall state of the computer book market. But most of our readers don't care about the publishing business. They care about the technologies we cover. Here's where we get to the meat: category visualizations and trends showing which technologies are winning and which are losing in the book market. Here's a treemap view of the quarter on quarter differences between Q3 of 2006 and the same period last year:
As I've previously described in Book Sales as a Technology Trend Indicator, in a Treemap visualization, the size of a square indicates the relative size of the category, and its color indicates the rate of …
[Read more]
OK, it took a while, but it has been worth the wait. At last I
can now guarantee that when you download the PBXT source code, it
will compile! But seriously, with the released of MySQL 5.1.12
Beta we now have an excellent platform for testing the pluggable
storage engine API.
These are interesting times because we are seeing the future of
storage engines in MySQL. The PBXT 0.9.73 release demonstrates
the ease with which externally built storage engines can be
combined with MySQL in the future. And, as I have mentioned
before, PrimeBase XT is the first engine to take full advantage
of this new feature in MySQL.
And while I am singing my praises let me remind you of 2 other
reasons why you should try out PBXT: the engine achieves high
concurrency using a pure MVCC implementation (MVCC stands for
multi-generational concurrency control, if you want to know why,
ask Jim! ;) and great performance with a write-once …
Just a quick reminder: the Hamburg MySQL User Group meets tonight at 7pm at the usual place. See the invitations on Meetup.com or OpenBC/Xing for details - around 25 people have signed up so far, so we should have a great time. Stefan Saasen will give a talk about Ruby on Rails/Active Record. See you there!