Re: Postgres-R: primary key patches

markus(at)bluegap(dot)ch (Markus Wanner) writes:
> as you might know, Postgres-R relies on primary keys to address tuples
> of a table. It cannot replicate tables without a primary key.

Slony-I does the same, with the "variation" that it permits the option
of using a "candidate primary key," namely an index that is unique+NOT
NULL.

If it is possible to support that broader notion, that might make
addition of these sorts of logic more widely useful.

> Primary keys currently aren't really used within the executor, so I
> had to extended and modify Postgres here and there, to get the
> required information. To ease reviewing I have split out these
> modifications and present them here as two separate little patches.

I know Jan Wieck has in mind the idea of adding an interface to enable
doing highly efficient IUD (Insert/Update/Delete) via generating a way
to do direct heap updates, which would be *enormously* more efficient
than the present need (in Slony-I, for instance) to parse, plan and
execute thousands of IUD statements. For UPDATE/DELETE to work
requires utilizing (candidate) primary keys, so there is some
seemingly relevant similarity there.
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