Properties:
| Applicable To | InnoDB |
| Server Startup Option | --innodb-additional-mem-pool-size=<value> |
| Scope | Global |
| Dynamic | No |
| Possible Values | Integer: Range: 524288 (512K) - 4294967295 (4G) |
| Default Value | 1048576 (1M) |
| Category | Performance |
Description:
As per MySQL documentation, this pool is used to store data …
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MySQL has User Defined Functions. These are loadable modules,
written in C, that can be loaded into a running MySQL server, and
used like a "native" built-in function.
A UDF can be an aggregate function. An aggregate function is one
that takes in multiple rows, but emits only one result. For
example, SUM() is a built-in aggregate function.
I just proved to myself via testing and benchmarking that user
defined aggregate functions are about three times slower than the
call interface to the built-in functions.
THREE TIMES SLOWER!
In about twelve hours I am supposed to be presenting a talk
titled Using User-defined Functions and Aggregates to Speed
Up Your Data Warehouse Processing.
Um. Yeah...
UPDATE:
It turns out to be a MacOS thing. On Linux, the …
There is a fair amount of photography happening at the MySQL
UC.
In a pure happenstance, the CEO of Sun, Johnathan Schwartz, and
myself, ended up in the same frame. Almost
That's me, or at least about a third of me, on the left edge.
This morning, as I was looking for some introductory material on a programming language, I came across a document which would probably have done the job just right. It’s just that this particular document, despite its excellent technical points and clear explanation, will end up turning away a lot of its potential readers.
It’s written in English, which means that it is accessible to a very large part of the world’s population. Even where English as a second language is not that wide-spread, I think it’s fair to say that anyone interested in programming a computer is forced into learning at least basic English. People in India (pop. 1.1 billion) certainly read English, and I’ve met many Chinese (pop. 1.3 billion) with excellent English skills.
In other words, if you’re writing programming books in English, your potential readership is quite a bit larger than you might have originally thought. And yet, this document, like …
[Read more]People reading this blog & friends have certainly noted my excitement about China in the last year.
Therefore I am pleased to disclose that I have been invited and I have joined advisory board of TargetSource, a newly formed Open Source company based in Beijing.
For more info see TargetSource Official Launch
I will soon interview Peter Cheng, the founder of the company, to share some of his ideas and vision for building Open Source business out of China.
It is not always easy to scale Drupal -- not because Drupal sucks, but simply because scaling the LAMP stack (including Drupal) takes no small amount of skill. You need to buy the right hardware, install load balancers, setup MySQL servers in master-slave mode, setup static file servers, setup web servers, get PHP working with an opcode cacher, tie in a distributed memory object caching system like memcached, integrate with a content delivery network, watch security advisories for every component in your system and configure and tune the hell out of everything.
…
[Read more]"We can do that cheaply, at a high cost."
Looking into InnoDB docs I found list of names of future InnoDB file formats: Antelope, Barracuda, Cheetah, Dragon, Elk, Fox, Gazelle, Hornet, Impala, Jaguar, Kangaroo, Leopard, Moose, Nautilus, Ocelot, Porpoise, Quail, Rabbit, Shark, Tiger, Urchin, Viper, Whale, X, Y and Zebra.
Aren't there animals starting on X and Y?
Entry posted by Vadim | 14 comments
[Read more]If you’re at the MySQL Conference and Expo, you can get a free sample chapter of the upcoming High Performance MySQL Second Edition. Just go to the exhibition area. As you go through the doors, take an immediate left and look for the sample chapter on O’Reilly’s table. It’s a rough draft and contains typos and my incredibly crude drawings instead of those that will go into the final book, but it should serve to give you an idea of the book’s depth and scope. Kudos to Andy Oram, our editor, who was able to get these done for us on very short notice.
Today is the first day at the conference (aside from the tutorials, which were yesterday). Here’s what I went to:
New Subquery Optimizations in 6.0
By Sergey Petrunia. This was a similar session to one I went to last year. MySQL has a few cases where subqueries are badly optimized, and this session went into the details of how this is being addressed in MySQL 6.0. There are several new optimization techniques for all types of subqueries, such as inside-out subqueries, materialization, and converting to joins. The optimizations apply to scalar subqueries and subqueries in the FROM clause. Performance results are very good, depending on which data you choose to illustrate. The overall point is that the worst-case subquery nastiness should be resolved. I’m speaking of WHERE NOT IN(SELECT…) and friends. It remains to be seen how this shakes out as 6.0 matures, and what edge cases will pop up.
The Lost Art Of the Self …
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