Re: patch for parallel pg_dump

Robert Haas <robertmhaas@gmail.com> writes:
> But the immediate problem is that pg_dump.c is heavily reliant on
> global variables, which isn't going to fly if we want this code to use
> threads on Windows (or anywhere else).  It's also bad style.  So I
> suggest that we refactor pg_dump.c to get rid of g_conn and g_fout.

I've looked at that a bit in the past and decided that the notational
overhead would be too much.  OTOH, if we're going to be forced into it
in order to support parallel pg_dump, we might as well do it first in a
separate patch.

> ...  But it
> seems possible that we might someday want to dump from one database
> and restore into another database at the same time, so maybe we ought
> to play it safe and use different variables for those things.  So I'm
> inclined to think we could just add a "PGconn *remote_connection"
> argument to the Archive structure (to go with all of the similarly
> named "remote" fields, all of which describe the DB to be dumped) and
> then that would be available everywhere that the Archive itself is.

I always thought that the "remote" terminology was singularly unhelpful.
It implies there's a "local" connection floating around somewhere, which
of course there is not, and it does nothing to remind you of whether the
connection leads to a database being dumped or a database being restored
into.  If we are going to have two fields, could we name them something
less opaque, perhaps "src_connection" and "dest_connection"?
        regards, tom lane