Re: estimating table size - Mailing list pgsql-general

From Bruce Momjian
Subject Re: estimating table size
Date
Msg-id 200407270328.i6R3S8k11181@candle.pha.pa.us
Whole thread Raw
In response to Re: estimating table size  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
I just updated the FAQ to suggest 32 as the header size (I am assuming
OID's and 4-byte alignment).  I am also assuming 7.5 which will loose
the cmin/cmax compression.

---------------------------------------------------------------------------

Tom Lane wrote:
> Ian Barwick <barwick@gmail.com> writes:
> > There is a little info in the FAQ:
> > http://www.postgresql.org/docs/faqs/FAQ.html
> > particularly sections 4.6 and 4.14
>
> I think the calculation in section 4.6 is out of date --- it's been
> awhile since row headers were 36 bytes.  The more correct number is
> between 24 and 32 bytes depending on whether you created the table
> WITH OIDS and whether your machine requires 4- or 8-byte alignment.
>
>             regards, tom lane
>

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

pgsql-general by date:

Previous
From: Tom Lane
Date:
Subject: Re: parsing binary varchar[]-s
Next
From: "Scrappy"
Date:
Subject: Re: Incoming Message