Re: Multicolumn index corruption on 8.4 beta 2

Florian Weimer wrote:
> * Josh Berkus:
>
> > Our documentation has been clear, back to version 7.0, that turning
> > fsync=off carries the risk that you will have to recreate your entire
> > database in the event of unexpected shutdown. That's not new.
>
> The documentation does not say this. Instead, there's the following
> rather explicit explanation that only OS crashes matter:
>
> | (Crashes of the database software itself are not a risk factor
> | here. Only an operating-system-level crash creates a risk of
> | corruption.)
>
> If it really matters how PostgreSQL is shut down in "fsync = off" mode
> (while the operating system keeps running), the documentation is
> seriously wrong here.

Yeah, AFAICT the writes are handed off to the operating system (just not
synced), so if it flushes its caches sanely at all there shouldn't be a
problem.

--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support