From: Björn Wittich <Bjoern_Wittich@gmx.de>
To: pgsql-performance@postgresql.org
Subject: query a table with lots of coulmns
Date: Fri, 19 Sep 2014 13:51:33 +0200
Message-ID: <541C18C5.3080204@gmx.de> (raw)
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>
Hi mailing list,
I am relatively new to postgres. I have a table with 500 coulmns and
about 40 mio rows. I call this cache table where one column is a unique
key (indexed) and the 499 columns (type integer) are some values
belonging to this key.
Now I have a second (temporary) table (only 2 columns one is the key of
my cache table) and I want do an inner join between my temporary table
and the large cache table and export all matching rows. I found out,
that the performance increases when I limit the join to lots of small parts.
But it seems that the databases needs a lot of disk io to gather all 499
data columns.
Is there a possibilty to tell the databases that all these colums are
always treated as tuples and I always want to get the whole row? Perhaps
the disk oraganization could then be optimized?
Thank you for feedback and ideas
Best
Neo
--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: Bjoern_Wittich@gmx.de
Subject: Re: query a table with lots of coulmns
In-Reply-To: <541C18C5.3080204@gmx.de>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox