Re: WIP: Access method extendability

On 11/10/2014 10:30 PM, Alexander Korotkov wrote:

Don't allowing CREATE ACCESS METHOD command seems problematic for me. How
could it work with pg_upgrade? pg_dump wouldn't dump extra pg_am records.
So, pg_upgrade would break at creating operator classes on new cluster. So,
I agree with dropping create am command only if we let pg_dump to dump
extra pg_am records...

pg_dump would dump the CREATE EXTENSION command, and the extension's installation script inserts the row to pg_am. pg_dump doesn't dump objects that are part of an extension, so that's how this would work with the CREATE ACCESS METHOD command, too.

Backtracking a bit, to summarize the discussion so far:

* It would be nice to have indexes that are not WAL-logged, but are automatically re-created after a crash. But it's a completely different and orthogonal feature, so there's no need to discuss that further in this thread.

* If an extension is buggy, it can crash and corrupt the whole database. There isn't really anything we can do about that, and this patch doesn't make that any better or worse.

* CREATE ACCESS METHOD command isn't worth it.