Re: GUC assign hooks (was Re: wal_buffers = -1 and SIGHUP)

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Bernd Helmle <mailings@oopsware.de>, pgsql-hackers@postgresql.org
Date: 2011-04-03T23:16:32Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Sun, Apr 3, 2011 at 1:26 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> IMO the real problem is essentially that GUC assign hooks have two
>> functions, checking and canonicalization of the value-to-be-stored
>> versus executing secondary actions when an assignment is made; and
>> there's no way to get at just the first one.

> Yes, I think that's right.  A related point is that the API for assign
> hooks is not consistent across all data types: string assign hooks can
> return a replacement value, whereas everyone else can only succeed or
> fail.

Right.  In the original design we only foresaw the need to canonicalize
string values, so that's why it's like that.  This change will make it
more consistent.

			regards, tom lane