Re: Putting many related fields as an array

On Tue, May 12, 2009 at 08:06:25PM +0800, Ow Mun Heng wrote:
> From: pgsql-general-owner(at)postgresql(dot)org [mailto:pgsql-general-
> On Tue, May 12, 2009 at 01:23:14PM +0800, Ow Mun Heng wrote:
> >Not sure why this is better than using separate columns though. Maybe a
> >new datatype and a custom aggregate would be easier to work with?
>
> The issue here is the # of columns needed to populate the table.
>
> The table I'm summarizing has close to between 50 to 100+ columns, if the
> 1:5x is used as a yardstick, then the table will get awfully wide quickly.
>
> I need to know how to do it first, then test accordingly for performance and
> corner cases.

Yes, those are going to be pretty wide tables! Maybe if you can make
the source tables a bit "narrower" it will help things; PG has to read
entire rows from the table, so if your queries are only touching a few
columns then it's going to need a lot more disk bandwidth to get a
specific number of rows back from the table.

--
Sam http://samason.me.uk/