Re: persistent connections, AOLserver (Was: [SQL] maybe Offtopic : PostgreSQL & PHP ?)

On Wed, Apr 18, 2001 at 08:28:14PM +0200, Mathijs Brands wrote:

> I've seen both MySQL and PostgreSQL give up (MySQL just hung, pgsql
> cored) when I tried simple selects from a couple of hundred concurrent
> connections; no transactions or other fancy stuff there. I think I was
> using MySQL 3.22.?? and pgsql 6.5.3, so more modern versions may well be
> able to cope with these numbers of connections. It's been more than a
> year since I last tried it.

I can see that happenning in 6.5, but not in later versions.

> I don't know what the current state of affairs is, but it is my
> understanding that, while pgsql performs admirably on tasks which mostly
> read data, pgsql isn't really able to cope (performance wise) with an
> application that has a very high insert to select ratio, such as OLTP.
> I'm looking into using pgsql to for implementing datamarts for a CRM
> application, so I'll so how that goes in the next couple of weeks. I'm
> keeping my fingers crossed ;)

I think you got that backwards. PG is the one who can deal with OLTP
well. MySQL with its pessimistic locking model just hangs forever. Take a
look at Tim Perdue's tests with SourceForge on phpbuilder.com

> The reason for the previous paragraph is that I think pgsql (PHP even
> more so) is mosty used for databases in which the insert to select ratio
> is much more favourable. But hey, that's my opinion.

Another misconception. Unless your site is very very simple, you have
_plenty_ of INSERTs and UPDATEs. On my sites, _every_ http request
requires at least 2 SELECTs and 1 INSERT, plus all the other stuff they
are doing. That's so I can keep track of who is visiting what. On MySQL
this would be unbearable.

-Roberto

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Roberto Mello - Computer Science, USU - http://www.brasileiro.net
http://www.sdl.usu.edu - Space Dynamics Lab, Developer
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