Date: Tue, 16 Nov 2010 11:50:55 +0100
From: Louis-David Mitterrand <vindex+lists-pgsql-performance@apartia.org>
To: pgsql-performance@postgresql.org
Subject: best db schema for time series data?
Message-ID: <20101116105055.GA26129@apartia.fr>
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Hi,

I have to collect lots of prices from web sites and keep track of their
changes. What is the best option?

1) one 'price' row per price change:

	create table price (
		id_price primary key, 
		id_product integer references product,
		price integer
	);

2) a single 'price' row containing all the changes:

	create table price (
		id_price primary key, 
		id_product integer references product,
		price integer[] -- prices are 'pushed' on this array as they change
	);

Which is bound to give the best performance, knowing I will often need
to access the latest and next-to-latest prices?

Thanks,