Re: WORM and Read Only Tables (v0.1)

On Tue, Dec 11, 2007 at 11:12:46AM +0000, Simon Riggs wrote:
>
> Read-Only Tables
> ----------------

In the past when this topic came up, there was some discussion of doing this
at a level somewhere below the table horizon. There are a number of nasty
limitations for partitions currently (not the least of which is that real
uniqueness guarantees are impractical), so allowing users to specify some
segment of the table to be "read only" without imposing it on the whole
table would be awful nice. I seem to recall Jan had an idea on how to do
it, but I could be wrong.

Also, doing this at the tuple, rather than table-wide, level might lead to
additional capabilities in this area:

> Attach
> ------
>
> Writing tables on one system and then moving that data to other systems
> is fairly common. If we supported read-only tables then you might
> consider how you would publish new versions to people.

Some time ago I was speculating on pie-in-the-sky features I might like in
Postgres, and it was something like this attach. But the idea was somehow
related to the read-only tuples.

In my specific case, I have piles and piles of mostly useless data.
Sometimes, however, some of that data is possibly useful in retrospect. So
the suggestion was to have tables that could be mostly offline -- archived
somewhere -- but for which we had enough metadata online to say, "You have
some data that might match in catalog C. Go mount it, and I'll check." I
think this is subtly different from the attach case you're outlining?

A