Re: Database directory names

On Tue, 2 Jul 2002, Kris Deugau wrote:

> I'm in the final stages of setting up database access for our domain
> hosting customers.  The current system is running PostgreSQL 7.0- with
> which I haven't met any major problems (other than trying to figure out
> how to restrict access to each domain's database- solved).
>
> However...  That box is slated for some major hardware upgrades, and an
> update from RedHat 7.0 to 7.3- bringing Postgres up to 7.2.  This is not
> in and of itself a problem...  but one particular attribute of 7.2 has
> me very puzzled and concerned.
>
> In 7.0, each database resided in /var/lib/pgsql/data/base/{database
> name}. This appears to have changed in 7.2 to an indecipherable number,
> with no apparent relation to the database name.
>
> I've spent a little time playing with
>    CREATE DATABASE dbname WITH LOCATION = 'dbpath';
> but it doesn't really suit my needs;  I don't want to specify where the
> base/ directory goes!  I don't need to.  I do want to be able to easily
> track disk usage on a per-database basis- and while I could just make
> note of the directory created when a database is created, it would be
> *much* simpler to automate information-generating scripts based on the
> database name directly.  (Nor do I want to hassle with trying to get
> appropriate environment variables set for the postmaster;  I *really*
> don't want to have to modify the init script.)
>
> Is this a feature, a bug, or a change related to some other critical
> functional capability of Postgres?  I haven't found anything else that
> meets our requirements here, and I can work around this annoyance if
> required- but I'd rather be lazy.  ;)

Switching to numbers for tables and databases helped a few things
(including for tables making it easier to rollback a drop table).
There's a contrib item, oid2name which will print out a mapping
of directory number to database name.  The readme gives an example
of using it with du.