Re: 9.6 and fsync=off - Mailing list pgsql-hackers

From Tom Lane
Subject Re: 9.6 and fsync=off
Date
Msg-id 1035.1462205069@sss.pgh.pa.us
Whole thread Raw
In response to Re: 9.6 and fsync=off  (Andres Freund <andres@anarazel.de>)
Responses Re: 9.6 and fsync=off  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
Andres Freund <andres@anarazel.de> writes:
> On 2016-05-02 10:07:50 -0400, Robert Haas wrote:
>> - If that flag is set on a subsequent startup, say:
>> WARNING: Recovery was previously performed with fsync=off; this
>> cluster may be irretrievably corrupted.

> Well, the problem with that is that postgres crashes are actually
> harmless with regard to fsync=on/off. It's just OS crashes that are a
> problem. So it seems quite likely that the false-positive rate here
> would be high enough, to make people ignore it.

That's a pretty good point.  Also, as sketched, I believe this would
start bleating after a crash recovery performed because a backend
died --- which is a case where we know for certain there was no OS
crash.  So this idea needs some more thought.
        regards, tom lane



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