Re: Re: ALTER SYSTEM SET command to change postgresql.conf parameters (RE: Proposal for Allow postgresql.conf values to be changed via SQL [review])

2013-08-06 19:41 keltezéssel, Bruce Momjian írta:
> On Tue, Aug  6, 2013 at 06:34:35PM +0200, Boszormenyi Zoltan wrote:
>> 2013-08-05 16:01 keltezéssel, Stephen Frost írta:
>>> * Greg Stark (stark@mit.edu) wrote:
>>>> On Fri, Aug 2, 2013 at 4:05 PM, Stephen Frost <sfrost@snowman.net> wrote:
>>>>>> I'm not even clear we do want this in /etc since none of our GUC
>>>>>> options are repeatable things like Apache virtual servers. It actually
>>>>>> makes *more* sense for pg_hba than it does for gucs. I think we can
>>>>>> assume that in the future we'll have something like it however.
>>>>> I tend to agree with this also, though I can imagine wanting to separate
>>>>> things in a conf.d directory ala exim's conf.d directories, to allow
>>>>> tools like puppet to manage certain things environment-wide (perhaps
>>>>> krb_server_keyfile) while other configuration options are managed
>>>>> locally.
>>>> Extensions are actually a pretty good argument for why conf.d in /etc
>>>> (or wherever the non-auto-config is) is pretty important useful.
>>>> That's the kind of thing conf.d directories are meant for. A user can
>>>> install a package containing an extension and the extension would
>>>> automatically drop in the config entries needed in that directory.
>>> Agreed, though I think there should be a difference between "shared
>>> library load" being added-to for extensions, and "random
>>> extension-specific GUC"..
>> Now that you mention "shared library load", it may be a good idea
>> to add an "append-to-this-GUC" flag instead of overwriting the
>> previous value. Two GUCs may make use of it: shared_preload_libraries
>> and local_preload_libraries. It would make packagers' of extensions
>> and DBA's lives easier.
> 'search_path' might also use it, though we might need append and
> prepend.

Indeed. Although I was thinking along the lines of the GUC parser, so:

shared_preload_library += 'some_new_lib'

would append to the old value.

Maybe "<+=" is intuitive enough for prepending, or someone may
come up with a better idea.

But the extra flag would still be needed to indicate the GUC is a list,
so these new operators are usable on them and not on regular GUCs.

Best regards,
Zoltán Böszörményi

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Zoltán Böszörményi
Cybertec Schönig & Schönig GmbH
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