Re: libpq object hooks (libpq events)

Alvaro Herrera wrote:
> Andrew Chernow escribió:
>> Attached is the latest patch. It has addressed the requested changes
>> found here:
>> http://archives.postgresql.org/pgsql-patches/2008-05/msg00389.php
>>
>> Its a tarball because there are two new files, libpq-events.c and
>> libpq-events.h. The patch is in the tarball as well as attached to the
>> email.
>
> I modified this patch slightly. I was about to try libpqtypes on it,
> but then I noticed that libpqtypes as published on pgfoundry is based on
> a very old version of this patch, so I punted. So, for now, the only
> guarantee is that it compiles with no warnings.
>

Being that it is now on pgfoundry, we didn't want to make drastic changes. We
wanted to wait to see how this patch unfolds and make a major change then.

"event" version of libpqtypes (not on foundry yet)
http://libpqtypes.esilo.com/libpqtypes-events.tar.gz

> (I also removed PQresultAlloc.)
>

Nooooooo ... removing PQresultAlloc breaks libpqtypes! It also removes some of
the use cases provided by PQsetvalue, which allows one to add to a result (in
our case from scratch).

> There's one thing that seems a bit baroque, which is the
> PG_COPYRES_USE_ATTRS stuff in PQcopyResult. I think that flag
> introduces different enough behavior that it should be a routine of its
> own, say PQcopyResultAttrs. That way you would leave out the two extra
> params in PQcopyResult.
>

Okay. We can move attr copying to its own function.

> Oh -- one last thing. I am not really sure about the flags to
> PQcopyResult. Should there really be flags to _remove_ behavior,
> instead of flags that add?
>

Agreed, that is kinda weird. Probably ended up that because the flags were an
after thought.

> However, the only change of any significance that I introduced was that
> a "name" is attached to every event proc, so that it can be reported in
> error messages, as reporting only %p seems very useless. (I also
> removed PQresultAlloc.)

I don't mind re-introducing the name, but Tom seemed very against this due to
conflicts. If 2 different libraries register the same name, debugging would be
painful.

> The main missing thing from this patch is SGML docs for the
> new libpq functions.

We have no issue here. We are waiting for the patch to gain acceptance so we
only document this once.

--
Andrew Chernow
eSilo, LLC
every bit counts
http://www.esilo.com/