Re: [BUGS] Breakage with VACUUM ANALYSE + partitions

On Fri, Apr 29, 2016 at 7:58 PM, Andres Freund <andres@anarazel.de> wrote:
> On 2016-04-28 17:41:29 +0100, Thom Brown wrote:
>> I've noticed another breakage, which I can reproduce consistently.
>
>> 2016-04-28 17:36:08 BST [18108]: [47-1] user=,db=,client= DEBUG:  could not
>> fsync file "base/24581/24594.1" but retrying: No such file or directory
>> 2016-04-28 17:36:08 BST [18108]: [48-1] user=,db=,client= ERROR:  could not
>> fsync file "base/24581/24594.1": No such file or directory
>> 2016-04-28 17:36:08 BST [18605]: [17-1]
>> user=thom,db=postgres,client=[local] ERROR:  checkpoint request failed
>> 2016-04-28 17:36:08 BST [18605]: [18-1]
>> user=thom,db=postgres,client=[local] HINT:  Consult recent messages in the
>> server log for details.
>
> Yuck. md.c is so crummy :(
>
> Basically the reason for the problem is that mdsync() needs to access
> "formally non-existant segments" (as in ones where previous segments are
> < RELSEG_SIZE), because we queue (and the might be preexistant) fsync
> requests via register_dirty_segment() in mdtruncate().

Shouldn't we just throw those flush requests away?

-- 
Robert Haas
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