[ forgot to comment on this part ]
Andrew Dunstan <andrew@dunslane.net> writes:
> To answer another point I see Tom made on the -general list: while
> individual backends may crash from time to time, crashes of the whole
> Postgres server are very rare in my experience in production
> environments.
Well, if you mean the postmaster darn near never goes down, that's true,
because we go out of our way to ensure it does as little as possible.
But that has got zip to do with this discussion, because a backend crash
has to be assumed to have corrupted unlogged tables. There are some
folk over in -general who are wishfully thinking that only a postmaster
crash would lose their unlogged data, but that's simply wrong. Backend
crashes *will* truncate those tables; there is no way around that. The
comment I made was that my experience as to how often backends crash
might not square with production experience --- but you do have to draw
the distinction between a backend crash and a postmaster crash.
regards, tom lane