Re: Allow GiST opcalsses without compress\decompres functions

On Wed, Sep 20, 2017 at 5:02 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

> Alexander Korotkov <a.korotkov@postgrespro.ru> writes:
> > On Wed, Sep 20, 2017 at 4:25 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> Yes.  We don't allow out-of-line values, but we do allow compressed and
> >> short-header values.
>
> > BTW, this comment looks still invalid for me...
>
> >> #define SIGLENINT  4 /* >122 => key will *toast*, so very slow!!! */
>
> I haven't done the math to see if 122 is exactly the right value,
> but at some point index_form_tuple would decide that the tuple was
> uncomfortably big and try to compress it.  So the comment is right
> in general terms.
>

If comment means toast as compression, not out-of-line storage then it's
true.
However, it would be good to rephrase this comment to clarify that.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company