Re: OK to put temp tablespace on volatile storage or to omit it from backups?

Ian Lawrence Barwick <barwick(at)gmail(dot)com> writes:
> 2013/5/1 Yang Zhang <yanghatespam(at)gmail(dot)com>:
>> That is unfortunate. Good thing I asked, I guess. Do you have a
>> pointer to said blog post?

> I think this is the post in question:
> http://thebuild.com/blog/2013/03/10/you-cannot-recover-from-the-loss-of-a-tablespace/

Appears to be sheer blather, or at least not tempered by any thoughts
of whether it'd work in special cases. The main reality underlying it,
I think, is that WAL replay will complain if files are missing. But
there will be no WAL log entries for temp tables.

The main concern I'd have about Yang's idea is that just because *he*
thinks a tablespace is "temp" doesn't mean the system knows it is,
so there would be no protection against accidentally creating a regular
table there; whereupon he's at risk of replay failures.

Having said that, there's no substitute for testing ;-). I wouldn't be
surprised for instance if the DB won't restart until you create the
tablespace directories, and maybe even PG_VERSION files therein. But it
really shouldn't have an issue with the files underlying a temp table
not being there anymore; at worst you'd get some bleats in the log.

regards, tom lane