Re: Patch to improve reliability of postgresql on linux nfs - Mailing list pgsql-hackers

From Florian Pflug
Subject Re: Patch to improve reliability of postgresql on linux nfs
Date
Msg-id 4CFAF680-B5B8-4A5A-9B40-9A84F9680BE8@phlo.org
Whole thread Raw
In response to Re: Patch to improve reliability of postgresql on linux nfs  (George Barnett <gbarnett@atlassian.com>)
Responses Re: Patch to improve reliability of postgresql on linux nfs
List pgsql-hackers
On Sep12, 2011, at 06:30 , George Barnett wrote:
> On 10/09/2011, at 1:30 AM, Bernd Helmle wrote:
>
>> --On 9. September 2011 10:27:22 -0400 Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>
>>> On the whole I think you'd be better off lobbying your NFS implementors
>>> to provide something closer to the behavior of every other filesystem on
>>> the planet.  Or checking to see if you need to adjust your NFS
>>> configuration, as the other responders mentioned.
>>
>> You really need at least mount options 'hard' _and_ 'nointr' on NFS mounts, otherwise you are out of luck. Oracle
andDB2 guys recommend those settings and without them any millisecond of network glitch could disturb things
unreasonably.
>
> My mount options include hard and intr.

If you really meant to say "intr" there (and not "nointr") then that probably explains the partial writes.

Still, I agree with Noah and Kevin that we ought to deal more gracefully with this, i.e. resubmit after a partial
read()or write(). AFAICS there's nothing to be gained by not doing that, and the increase in code complexity should be
negligible.If we do that, however, I believe we might as well handle EINTR correctly, even if SA_RESTART should prevent
usfrom ever seeing that. 

best regards,
Florian Pflug



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