Re: Physical Database Configuration - Mailing list pgsql-general

My solution did not involve tablespaces, but was more of a quick solution
to make it easier for admins to do _some_ sort of physical configuration.

The idea is that the developer could do something like

'create alternate location ALTERNATE_LOCATION_NAME for
DATABASE_OBJECT_NAME at "/PATH/TO/PHYSICAL/FILE";'

We would have a system table holding theses values. Then, all database
commands which create a file for an object, call open_object(oid,
object_name) or something to create the file object.  This will first look
in the new system table to see if there is a mapping for an object of this
name.  If so, it will create a symlink to "/PATH/TO/PHYSICAL/FILE" for the
oid before opening the file.

Anyway, if people are working on tablespaces, I'll defer to them.  This
small fix is something that I might actually have time to do, but
tablespaces definitely not.

Jon

On Wed, 25 Jun 2003 nolan@celery.tssi.com wrote:

> > Well, correct solution is to implement tablespaces on which objects like
> > databases, tables and indexes can be put.
>
> I've not looked at the SQL standard, but it seems to me like the order
> should be:
>
> Databases
>    Tablespaces
>       Schemas
>          Objects (tables, indexes, functions, etc.)
>
> And it really isn't hierarchical.  As I understand them (based on my
> Oracle background), tablespaces, unlike schemas, do NOT create a layer
> of data abstraction.   That is to say, while the same table name
> can exist in multiple schemas, only one instance of a given table name
> within a given schema can exist, regardless of what tablespace it is in.
>
> That makes the tablespace a property of an object.
>
> Whether or not two databases can share tablespaces isn't clear to me,
> though as a DBA I can think of good reasons why they probably shouldn't
> do so, I'm not sure if that is an absolute.
>
> > I have no idea what is the status of that effort right now. You can search the
> > archives or I hope this kicks a fresh discussion..:-)
>
> I'm game, though I'm also not ready to lead such a project, probably not
> even the discussion on it.
> --
> Mike Nolan
>
>
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