pg.ddx.io  pgsql-interfaces@postgresql.org mailing list archive  
help / color / mirror / Atom feed
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Matthew Hagerty <matthew@venux.net>
Cc: pgsql-interfaces@postgreSQL.org
Subject: Re: [INTERFACES] 8K query limit in 6.5?
Date: Tue, 13 Jul 1999 12:42:50 -0400
Message-ID: <23455.931884170@sss.pgh.pa.us> (raw)
In-Reply-To: <4.1.19990713115720.009c84b0@mail.venux.net>

Matthew Hagerty <matthew@venux.net> writes:
> ... please make this bigger!  Or tell me how and I'll do it. :)

"Find all the places that need fixing, and fix 'em." :-)
The devil is in the details ... and there are a lot of details.
You could probably get some useful functionality just by fixing
frontend libpq's output buffer and the query input buffer in
backend/tcop/postgres.c.  The trouble comes in cleaning up all the
details, like fixed-size buffers in COPY, pg_dump, etc etc etc etc.

Michael Ansley seems to be interested in working on this; I'd
suggest getting together with him if you want to help.

> Is it really such a big deal to increase the size of a query that pg can
> handle?  I'm talking about the size of a query submitted to pg, from what I
> understand there is no limit on the record (tuple) size that can be
> returned from pg.  Is my understanding correct?

There is a (quite unrelated) limit on the size of a tuple that can be
stored on disk, but AFAIK you can construct an arbitrarily large tuple
as the result of computations specified in a SELECT and it will be
passed back to your frontend application without trouble; as long as
you don't run out of memory on either side, that is.

Where we want to end up, of course, is no limit on the size of a disk
tuple either, but the code changes for that are almost entirely
unrelated to the ones that deal with the textual length of a query.
It's best tackled as two independent projects.

			regards, tom lane



view thread (8+ messages)  latest in thread

Message-ID: <23455.931884170@sss.pgh.pa.us>
Permalink:  ../23455.931884170@sss.pgh.pa.us/
Also on:    postgresql.org/message-id/23455.931884170@sss.pgh.pa.us

 · 

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-interfaces@postgresql.org
  Cc: tgl@sss.pgh.pa.us, matthew@venux.net
  Subject: Re: [INTERFACES] 8K query limit in 6.5?
  In-Reply-To: <23455.931884170@sss.pgh.pa.us>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox