Re: Higher TOAST compression.

From: "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
To: "Laurent Laborde" <kerdezixe(at)gmail(dot)com>, "PostgreSQL-development" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Higher TOAST compression.
Date: 2009-07-17 17:50:51
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-hackers

Laurent Laborde <kerdezixe(at)gmail(dot)com> wrote:

> What about trying to change the TOAST_TUPLE_TARGET to get a higher
> compression (by having more toasted record) ?
> I'd like to change the TOAST_TUPLES_PER_PAGE. Maybe from 4 to 8 ?
> Is that correct ? Did i missed something ?
> I did some statistics and i will have much more TOASTed record as
> most of them are between 1KB and 2KB.

It seems like it might be reasonable to have a separate threshold for
compression from that for out-of-line storage. Since I've been in
that code recently, I would be pretty comfortable doing something
about that; but, as is so often the case, the problem will probably be
getting agreement on what would be a good change.

Ignoring for a moment the fact that "low hanging fruit" in the form of
*very* large values can be handled first, the options would seem to

(1) Just hard-code a lower default threshold for compression than for
out-of-line storage.

(2) Add a GUC or two to control thresholds.

(3) Allow override of the thresholds for individual columns.

Are any of these non-controversial? What do people like there? What
did I miss?


In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message Josh Williams 2009-07-17 18:38:09 Review: Patch for contains/overlap of polygons
Previous Message Robert Haas 2009-07-17 17:41:34 Re: Enhancement - code completion when typing set search_path