To: "Scott Marlowe" <smarlowe@g2switchworks.com>,
	Marcos <mjs_ops@gmx.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: Decide between Postgresql and Mysql (help of
References: <1143559902.1241.16.camel@servidor>
	<1143572392.3625.79.camel@state.g2switchworks.com>
Message-ID: <op.s642dpyecigqcu@apollo13>
Date: Tue, 28 Mar 2006 21:42:51 +0200
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> This is as much about the code in front of the database as the database
> itself.  You'll want to use an architecture that supports pooled
> connections (java, php under lighttpd, etc...) and you'll want to look

	Well, anybody who uses PHP and cares about performance is already using  
lighttpd, no ?

> MySQL and PostgreSQL can handle fairly heavy parallel loads.

	I'll only speak about MyISAM. MySQL == MyISAM. InnoDB is useless : if you  
want transactions, use postgres.
	If you say to yourself "oh yeah, but it would be cool to use a MyISAM  
table for stuff like hit counters etc"... Is it the job of a SQL database  
to count hits on the root page of your site ? No. To store user sessions ?  
No. The job of a SQL database is to efficiently handle data, not to do  
something that should stay in RAM in the application server process, or at  
worst, in a memcached record.

	MySQL + MyISAM has a huge advantage : it can look up data in the index  
without touching the tables.
  	MySQL handles parallel SELECTs very well.

	However, throw in some maintenance operation which involves a long query  
with writes (like a big joined UPDATE) and all access to your website is  
blocked while the query lasts.
	This is worsened by the fact that MySQL sucks at complex queries.

	If all of your updates are done to a few rows, MyISAM is cool, but  
someday you'll want to do this query which locks a table during one  
minute... and then you got a problem.

	Just be very clear about what you want to do, what types of queries  
you'll want to run in two years... etc.