Re: OID vs overall system performances on high load

From: Andrew McMillan
Subject: Re: OID vs overall system performances on high load
Date: ,
Msg-id: 1117256890.30150.179.camel@lamb.mcmillan.net.nz
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In response to: OID vs overall system performances on high load databases.  ("Eric Lauzon")
Responses: Re: OID vs overall system performances on high load  (PFC)
List: pgsql-performance

On Fri, 2005-05-27 at 13:05 -0400, Eric Lauzon wrote:
> What are the effect of having a table with arround 500
> insert/update/delete on two to eight table in a time frame of 2
> minutes 24/24h, when you have oid enabled versus the same setup when
> you dont have oid?
>
> That deployment is done on a postgres with 8 to 9 databases, each
> having those 2 to 8 high load tables with oid enabled.
>
> Would the oid colum slow down table scan when you have over 20
> millions row?
>
> Would the cost of maintaining the oid column inside thoses high load
> tables when there is no oid reference used for data seeking costy for
> postgres ressources!?

The OID column is an extra few bytes on each row.  If you don't have any
use for it (and let's face it: most of us don't), then create your
tables "without OID".

The amount of impact that it makes will depend on what the general row
size is.  If they are rows with a couple of integers then the size of an
OID column will be a significant portion of the size of each row, and
removing it will make the physical on-disk data size significantly
smaller.  If the size of the average row is (e.g.) 2k then the OID will
only be a very small fraction of the data, and removing it will only
make a small difference.

Regards,
                    Andrew McMillan.

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