From: Josh Berkus <josh@agliodbs.com>
Reply-To: josh@agliodbs.com
Organization: Aglio Database Solutions
To: Veikko =?iso-8859-1?q?M=E4kinen?= <veikko.makinen@ecom.fi>
Subject: Re: How does the transaction buffer work?
Date: Thu, 16 Jun 2005 14:53:36 -0700
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Veikko,

> One way of doing this that I thought of was start a
> transaction, delete everything and then just dump new data in (copy
> perhaps). The old data would be usable to other transactions until I
> commit my insert. This would be the fastest way, but how much memory
> would this use?

Starting a transaction doesn't use any more memory than without one.   
Unlike Some Other Databases, PostgreSQL's transactions occur in WAL and on 
data pages, not in RAM.

> Will this cause performance issues on a heavily loaded 
> server with too little memory even to begin with :)

Quite possibly, but the visibility issue won't be the problem.

-- 
--Josh

Josh Berkus
Aglio Database Solutions
San Francisco