Re: [HACKERS] Patching dblink.c to avoid warning about open

Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Well, as I said in the patch email:
>
> >     The reported problem is that dblink_open/dblink_close() (for cursor
> >     reads) do a BEGIN/COMMIT regardless of the transaction state of the
> >     remote connection.  There was code in dblink.c to track the remote
> >     transaction state (rconn), but it was not being maintained or used.
>
> You should lose the remoteXactOpen flag entirely, in favor of just
> testing PQtransactionStatus() on-the-fly when necessary.  Simpler,
> more reliable, not notably slower.
>
> With that change, the separate remoteConn struct could be dropped
> altogether in favor of just using the PGconn pointer.  This would
> make things notationally simpler, and in fact perhaps allow undoing
> the bulk of the edits in your patch.  As-is I think the patch is
> pretty risky to apply during beta.

The problem with not using rconn is that we are not saving the
transaction status at the _start_ of the cursor open.  If we don't do
that, we have no way of knowing on close if _we_ opened the transaction
or whether it was opened by the user.

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