From: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
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To: | Josh Harrison <joshques(at)gmail(dot)com> |
Cc: | Trevor Talbot <quension(at)gmail(dot)com>, pgsql-general(at)postgresql(dot)org |
Subject: | Re: postgresql storage and performance questions |
Date: | 2007-11-20 12:49:54 |
Message-ID: | 20071120124954.GE5167@alvh.no-ip.org |
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Thread: | |
Lists: | pgsql-general |
Josh Harrison escribió:
> > On 11/19/07, Josh Harrison <joshques(at)gmail(dot)com> wrote:
> >
> > > I have 2 tables with 2 cols each( 1 numeric(8,0) and 1 varchar(3) ).
> > > In table1 both the cols are filled and in table2 the varchar colm is null
> There were a couple of things we noted.
> 1. Tablesize twice as much than oracle-- Im not sure if postgres null
> columns has any overhead since we have lots of null columns in our
> tables.Does postgresql has lots of overhead for null columns?
No, NULLs are stored as a bitmap for each tuple and they are quite
efficient.
Probably the reason for the difference is the numeric field which Oracle
may be optimizing as a plain integer. Did you try declaring the column
as INTEGER in Postgres?
Please do not top-post.
--
Alvaro Herrera http://www.amazon.com/gp/registry/5ZYLFMCVHXC
"Everything that I think about is more fascinating than the crap in your head."
(Dogbert's interpretation of blogger philosophy)
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