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.

PG 7.0 was released almost 2 years ago, so you had a very old version when
you tried.

> 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.

This is simply not true. It may have been true in the past, but not since
PG 7.0 came out.

A mistake that I see MySQL users do frequently is that when they have a
bulk of inserts to do, they don't use the COPY command to bulk load the
data and/or they don't wrap the inserts into one (or several) transaction
blocks, leaving each INSERT in its own transaction, which obviously will
hurt performance.

They do that because they usually have no idea of what a database is for,
besides being an SQL interface to their file systems. Exactly what MySQL
was until very recently (and thanks to the work of third-parties, because
the MySQL team itself couldn't care less about real features).

-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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