Re: Modifying TOAST_TUPLE_THRESHOLD and TOAST_TUPLE_TARGET?

On Thu, Jun 11, 2009 at 5:12 PM, Kevin
Grittner<Kevin(dot)Grittner(at)wicourts(dot)gov> wrote:
>
> MAIN allows compression but discourages out-of-line storage.
> (Out-of-line storage will be performed only if the row is still too
> big after compression and out-of-line storage of EXTENDED and
> EXTERNAL columns.)

I had the impression the confusion was over the meaning of "too big"
rather than what "last resort" meant. So this doesn't seem any
clearer.

> It seems to me that MAIN might be a more useful option if it was more
> aggressive about avoiding out-of-line storage; perhaps only if the row
> doesn't fit by itself on a single page?  Does anyone else think so?

Yeah I think we're on the same page there. I do suspect the reason
this documentation is vague on the precise meanings of these options
is precisely because the author expected further tweaks of this nature
-- I don't know if this documentation has changed substantially since
toast was committed.

We've been talking about a number of ideas for making toast more
flexible but there are clearly an infinite number of permutations and
the trick will be figuring out how to present the useful ones without
making things too complicated for the user to control.

--
greg
http://mit.edu/~gsstark/resume.pdf