Re: Backend Question

Chris Bitmead <chris@bitmead.com> writes:
> Can anyone tell me what the concept of a "group" is in
> backend/libpq/portal.c? There are functions like PQntuplesGroup,
> PQfnumberGroup, PQfsizeGroup, PQftypeGroup etc etc.

Once upon a time it probably supported something like the ability to
merge tuples of different types into a SELECT result.  It does not
now: a little scanning shows there is no way to get no_groups above 1
in the current logic.

You should realize, however, that all that backend-PQexec code is dead
code and has been for a long time.  It's unlikely that it works at all
any more, considering all the changes that have gone on while it sits
untested on the sidelines.  I proposed ripping it out a few months ago,
and no one objected ... but I haven't got round to it yet.
        regards, tom lane