Don Baccus <dhogaza@pacifier.com> writes:
> This would need to be done to implement some sort of tablespace-style
> facility, too, right? I'm off Xun's thread in asking but I've been
> wondering. DBs like Oracle allow you to place tables and indices
> whereever you like in the filesystem. This is normally done to
> distribute things across different spindles, and in large, busy
> databases makes a significant difference. I've done some experimenting
> moving index files to a different spindle (using "ln" to fool
> postgres, of course) and insertions go measurably faster. Spindles
> are so cheap nowadays :)
As you say, you can fake it manually with symbolic links, but that's
a kluge.
The "database location" stuff that Peter and Thomas have been arguing
about is intended to allow a single postmaster to control databases that
are in multiple physical locations --- but there seems to be some debate
as to whether it works ;-). (I never tried it.) In any case, we don't
currently have any official provision for controlling location at finer
than database level. It'd be nice to be able to push individual tables
around, I suppose.
This wouldn't require a new storage manager, since presumably you'd
still be using the Unix-filesystem storage manager. The trick would be
to allow a path rather than just a base file name to be specified
per-relation. I'm not sure if it'd be hard or not. Probably, all the
system tables would have to stay in the database's default directory,
but maybe user tables could be given path names without too much
trouble...
regards, tom lane