Re: PostgreSQL configuration

> Dennis Bjorklund <db(at)zigo(dot)dhs(dot)org> writes:
>> On Thu, 8 Apr 2004 pgsql(at)mohawksoft(dot)com wrote:
>>> more flexable configuration based on the idea that configuration and
>>> data
>>> are in SEPARATE locations is important.
>
>> Why is it important and wouldn't it just make it harder to have several
>> database clusters (for example with different locale) or several
>> versions
>> of pg installed at the same time?
>
> My recollection of the arguments against were first that and second
> reliability --- there was concern about getting config and data of
> multiple installations mixed up if they weren't kept together. In the
> worst case you could conceivably bollix an installation unrecoverably
> that way. (Right now I do not think there is anything quite that
> critical in postgresql.conf, but someday there might be. My very vague
> recollection is that the proposed patch changed things so that WAL and
> DATA directories would be separately specified in the config file; if
> correct, mismatching them definitely would be a great chance to shoot
> oneself in the foot.)

The patch I had kept the directory layout as one single setting, just that
postgresql,conf was able to contain the location of pg_hba.conf,
pg_ident.conf, and the data directory.

Thus, one could start PostgreSQL as:
postmaster -C /etc/postgres/webdb.conf

Which would allow full configuration from that one file.

>
> I've recently had some very unpleasant experiences trying to install
> test versions of MySQL on machines that already had older versions
> installed normally. It seems that MySQL *will* read /etc/my.cnf if it
> exists, whether it's appropriate or not, and so it's impossible to have
> a truly independent test installation, even though you can configure it
> to build/install into nonstandard directories. Let's not emulate that
> bit of brain damage.

MySQL is, in general, unpleasent, but that is more or less a packaging issue.