Re: PostgreSQL configuration - Mailing list pgsql-hackers

> I just had a thought about this: seems like a big part of the objection
> is the risk of specifying -C and -D that don't go together.  Well, what
> if they were the same switch?  Consider the following simplification of
> the proposed patch:

I was really excited about this idea, then I thought about it, and while
it would answer some of the issues I mean to address, I find myself a
little disappointed that some of the functionality I wanted, i.e. multiple
databases with the same configuration, was not possible. However,
compromise is good.

>
> 1. Postmaster has just one switch, '-D datadir' with fallback to
> environmental variable PGDATA, same as it ever was.

I like this, I think, ... but it removes the posibility to run the same
configuration with the same database. This scenario is one of my "best
case" reasons why I think my patch is good, but, I think I can get 99% of
what I'm looking for with my modification outlined at the bottom of this
post.


>
> 2. The files that must be found in this directory are the configuration
> files, namely postgresql.conf, pg_hba.conf, pg_ident.conf.  (And any
> files they include are taken as relative to this directory if not
> specified with absolute path.  We'll still add the #include facility
> to postgresql.conf; the others have it already IIRC.)

My patch *already* has this functionality if it is a directory. I agree
with this, it was suggested (maybe even by you) over a year ago.


[snip -- good stuff]

Tom, this is great! I think we are almost there and I really appreciate
your flexibility in view of my obstinance. :-)

I like what you suggest, While I don't get the -D and -C functionality
(which I don't use, but thought was cool), I think I would like to add one
thing:

postmaster -D /etc/postgres/postgresql.conf

If the path specified is a config file, then "data_dir" MUST address a
valid PostgreSQL data directory.

So, here is (how I see) the logical breakdown of the feature:

"postmaster -D /somedir/data" works as it always has, it points to the
data dirtectory in which all the various config files live. If No
"data_dir" is specified, then "/somedir/data" is assumed to be where base,
pg_xlog, pg_clog, and etc. reside.

If, however, "data_dir" is specified, the data oriented elements like
"global," "base," "pg_clog," and "pg_xlog" are contained within that
directory. (In the future, we may be able to specify these locations
separately)

If "postmaster -D /etc/postgresql.conf" points to a file, then that file
MUST specify the location of "data_dir," "hba_conf," and "ident_conf."

Like I said, while I don't get the convenience of combining "-D ..." and
"-C ..." I do get most of what I'm asking for.

If this works for all you guys, I'll submit a patch Wednesday.