Re: Multicolumn index corruption on 8.4 beta 2 - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: Multicolumn index corruption on 8.4 beta 2
Date
Msg-id 20090609173734.GF5938@alvh.no-ip.org
Whole thread Raw
In response to Re: Multicolumn index corruption on 8.4 beta 2  (Florian Weimer <fweimer@bfk.de>)
Responses Re: Multicolumn index corruption on 8.4 beta 2  ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>)
List pgsql-hackers
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


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