Skip site navigation (1) Skip section navigation (2)

Re: Toast, Text, blob bytea Huh?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Peter T Mount <peter(at)retep(dot)org(dot)uk>
Cc: Joe Conway <joseph(dot)conway(at)home(dot)com>, jason(dot)ory(at)ndchealth(dot)com, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Toast, Text, blob bytea Huh?
Date: 2001-08-24 15:15:07
Message-ID: 3241.998666107@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackers
Peter T Mount <peter(at)retep(dot)org(dot)uk> writes:
> Quoting Joe Conway <joseph(dot)conway(at)home(dot)com>:
>> indicating that the practical limit is closer to 1 GB -- not sure why).

> It may be something to do with the 1Gb splitting of the physical files 
> representing a table...

No, that's just a coincidence.  The reason that TOAST limits fields to
1Gb is that the high-order two bits of the varlena length word were
commandeered as TOAST state indicators.  There are now only thirty bits
available to represent the length of a variable-length Datum; hence the
hard limit on field width is 1Gb.

I'd think that the "practical" limit is quite a bit less than that, at
least until we devise an API that lets you read and write toasted values
in sections.

			regards, tom lane

In response to

Responses

pgsql-hackers by date

Next:From: Hannu KrosingDate: 2001-08-24 15:33:43
Subject: Re: User locks code
Previous:From: Bruce MomjianDate: 2001-08-24 14:57:28
Subject: Re: A couple items on TODO

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group