Date: Wed, 4 Jun 2008 10:35:49 -0400
From: Aidan Van Dyk <aidan@highrise.ca>
To: Andreas Pflug <pgadmin@pse-consulting.de>
Cc: Decibel! <decibel@decibel.org>, Tom Lane <tgl@sss.pgh.pa.us>,
	Greg Smith <gsmith@gregsmith.com>,
	Peter Eisentraut <peter_e@gmx.net>, pgsql-hackers@postgresql.org,
	Josh Berkus <josh@agliodbs.com>
Subject: Re: Overhauling GUCS
Message-ID: <20080604143548.GE14498@yugib.highrise.ca>
References: <48409D1E.3070208@agliodbs.com>
	<200806010032.53337.peter_e@gmx.net>
	<Pine.GSO.4.64.0806020452220.26912@westnet.com>
	<17932.1212415926@sss.pgh.pa.us>
	<20080604131810.GH65238@decibel.org>
	<4846A483.8000001@pse-consulting.de>
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* Andreas Pflug <pgadmin@pse-consulting.de> [080604 10:20]:

> Hiding the storage of config parameters opaquely behind an API is 
> something I've been hating for a long time on win32.

;-)

> When reading this thread, I'm wondering if anybody ever saw a config 
> file for a complex software product that was easily editable and 
> understandable. I don't know one. If there was one, it'd be nice to know 
> it so we can learn from it.

PostreSQL, Apache, X.org

They are all easily editable, and "understandable", in the sense that I
understand that I'm supposed to edit the line, changing the value
(following the comments list of accepted values)

They are "less understandable" if you mean that I know the implications
of any change I make.  But guess what, having those values inputed
through some other mechanism (like a GUI config file editor, a SQL statement,
or a nice pgadmin-SQL-hiding-interface isn't going to change that part
of "understandable".  That part of understandable only comes through
good documentation and reference material, which is universally
applicable to any config method.

> IMHO the best compromise in machine and human readability is an XML 
> format. It's easily decorateable with comments, easily interpreted and a 
> pg_settings view could enhance it with even more comments, so an editor 
> using pgsql functions (to read and write postresql.conf.xml) could be 
> enabled to supply comprehensive help.

Well, In my past, I've generally not got around to installing and using
software that reqired me to edit some jumble of XML.  Ya, maybe I'm
lucky.  And since I've got a lot invested in PG, I'ld be forced to of PG
moved to an XML config, but I'ld be forced to kicking and screaming...

I just *know* that I'ld reload/restart postmaster some time, and the
config file wouldn't be quite correct, and I'ld search for 10 minutes
trying to find the extra (or lack) ", or missing closing /...  But maybe
most people are better at parsing XML than me.  And that also may be
because I've actively avoided it for so long ;-)

I don't know *how* I'ld decorate my XML config file with comments and
history the way I do my text-based #-commented config files.

a.


-- 
Aidan Van Dyk                                             Create like a god,
aidan@highrise.ca                                       command like a king,
http://www.highrise.ca/                                   work like a slave.

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