Re: Psql patch to show access methods info

Hi!

Thank you for the review.  Revised patch is attached.

On Wed, Jan 22, 2020 at 1:33 AM Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
> I think I would like this feature to be in, but I'm not sure that the
> shape is final yet.  My points:
>
> a) I don't see any use for \dA as presented; I think the \dA+ output is
>    useful.  Therefore my preference would be that \dA presents what the
>    latest patch has as \dA+.  I think we should leave \dA+ unimplemented
>    for now; maybe we can use some use for it later on.

Neither \dA or \dA+ are introduced or affected by this patch.  If we
like to change their behavior, we should probably do this separately
from this patch.

> b) I think \dAp should list the function used for each support proc.  I
>    don't have any use for \dAp actually (I already said that upthread,
>    sorry for repeating myself), but I think that if we have it, then
>    showing only the proc number is pointless.

It was shown by \dAp+.  But I agree that it's essential information
that is unreasonable to hide under verbose option.  So, procedure name
is always shown now.  I've also renamed "Support function" column to
"Number".

> c) it would be damn handy if \dAf (maybe \dAf+) lists the datatypes that
>    each opfamily has opclasses for.  Maybe make the output an array, like
>    {int4,int8,numeric,...}  Something like [*] but somehow make it
>    prettier?

I made this change, but using subselect in target list.  It's probably
slower query, but better code readability IMHO.

> d) This one I'm unsure about: should we list the opfamily for each
>    opclass in \dAc?  I'm not sure whether it's useful for anything.

It's already shown by \dAc+ and I think this behavior is fine.

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