Horton

Re: Mark all GUC variable as PGDLLIMPORT

Chapman Flack <chap@anastigmatix.net>

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From: Chapman Flack <chap@anastigmatix.net>
To: Robert Haas <robertmhaas@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Bruce Momjian <bruce@momjian.us>, Julien Rouhaud <rjuju123@gmail.com>, Michael Paquier <michael@paquier.xyz>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-08-23T21:07:57Z
Lists: pgsql-hackers 
On 08/23/21 14:30, Robert Haas wrote:
> it seems likely that this proposed
> API would have the exact same problem, because it would let people do
> exactly the same thing. And, going through this proposed API would
> still be significantly more expensive than just accessing the bare
> variables, because you'd at least have to do some kind of lookup based
> on the GUC name

I think the API ideas in [0] would not let people do exactly the same thing.

They would avoid exposing the bare variables to overwrite. Not that
there has been any plague of extensions going and overwriting GUCs,
but I think in some messages on this thread I detected a sense that
in principle it's better if an API precludes it, and that makes sense
to me.

The second idea also avoids the expense of name-based lookup (except once
at extension initialization), and in fact minimizes the cost of obtaining
the current value when needed, by slightly increasing the infrequent cost
of updating values.

Regards,
-Chap


[0] https://www.postgresql.org/message-id/6123C425.3080409%40anastigmatix.net

Commits

  1. Remove PGDLLIMPORT marker from __pg_log_level

  2. Mark a few 'bbsink' related functions / variables static.

  3. Add some missing PGDLLIMPORT markings

  4. Apply PGDLLIMPORT markings broadly.

  5. Helper script to apply PGDLLIMPORT markings.

  6. Simplify declaring variables exported from libpgcommon and libpgport.