I'll consider delayed_commits.
The database was 85MB before compaction. We ran compact and it was still 85Mb.
So compact didn't work. The same db on other servers will compact ~10x its
original size.
> I strongly suggest disabling delayed_commits on general principles (what's
> written should stay written). Are you able to compact the database(s) that
> give this error?
>
> B.
>
> On 7 Aug 2012, at 18:42, stephen bartell wrote:
>
>> delayed_commits = true
>>
>> Stephen Bartell
>>
>> On Aug 7, 2012, at 10:39 AM, Robert Newson wrote:
>>
>>> Are you running with delayed_commits=true or false?
>>>
>>> B.
>>>
>>> On 7 Aug 2012, at 18:27, stephen bartell wrote:
>>>
>>>>
>>>>> Hi Stephen,
>>>>>
>>>>> Can you tell us anymore about the context, or did you start seeing these
>>>>> in the logs?
>>>>
>>>> Sure, here's some context. This couch is part of a demo server. It
>>>> travels a lot and is cycled a lot. There is one physical server, it
>>>> consists of nginx (serving web apps and reverse proxying for couch),
>>>> couchdb for persistence, and numerous programs which read and write to
>>>> couch. Traffic on couch can get very heavy.
>>>>
>>>> I didn't first see this in the logs. Some of the web apps would grind to
>>>> a halt, nginx would return 404, and then eventually couch would restart.
>>>> This would happen every couple of minutes.
>>>>
>>>>> By chance do you have a scenario that reproduces this? Was this db
>>>>> compacted or replicated from elsewhere?
>>>>
>>>> I wish I had a pliable scenario other than sending the server through taxi
>>>> cabs, airlines, and pulling the power cord several times a day. We
>>>> haven't seen this on any of our production servers.
>>>> This server was not subject to any replication. Most databases on it are
>>>> compacted often.
>>>>
>>>> Last night we were able to drill down to one particular program which was
>>>> triggering the crash. One by one, we backed up, deleted, and rebuilt the
>>>> databases that program touched. There was one database which seemed to be
>>>> the culprit, lets call it History. History is a dumping ground for stale
>>>> docs from another db. History is almost always written to, and rarely read
>>>> from. We don't compact History since all docs in it are one revision
>>>> deep. We never replicate to or from it. The only reason we deem History
>>>> the culprit is because after rebuilding it, there hasn't been a crash for
>>>> over 12 hours.
>>>>
>>>> I have an additional question. Is it possible to turn couch logging off
>>>> entirely, or would redirecting to dev/null suffice? When couch would
>>>> crash, hundreds of MB of crap would get dumped to the log. (
>>>> {{badmatch,{ok,<<32,50,48,48,10 … 'hundreds of MB of crap' …
>>>> ,0,3,232>>}}). Right when this dump occurred, the cpu spiked and the
>>>> server began its downward descent.
>>>>
>>>> Best
>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Bob
>>>>> On Aug 7, 2012, at 2:06 AM, stephen bartell <[email protected]> wrote:
>>>>>
>>>>>> Hi all, could some one help shed some light on this crash I'm having.
>>>>>> I'm on v1.2, ubuntu 11.04.
>>>>>>
>>>>>> [Mon, 06 Aug 2012 18:29:16 GMT] [error] [<0.492.0>] ** Generic server
>>>>>> <0.492.0> terminating
>>>>>> ** Last message in was {pread_iolist,88385709}
>>>>>> ** When Server state ==
>>>>>> {file,{file_descriptor,prim_file,{#Port<0.2899>,79}},
>>>>>> 93302896}
>>>>>> ** Reason for termination ==
>>>>>> ** {{badmatch,{ok,<<32,50,48,48,10 … huge dump … ,0,3,232>>}},
>>>>>> [{couch_file,read_raw_iolist_int,3},
>>>>>> {couch_file,maybe_read_more_iolist,4},
>>>>>> {couch_file,handle_call,3},
>>>>>> {gen_server,handle_msg,5},
>>>>>> {proc_lib,init_p_do_apply,3}]}
>>>>>>
>>>>>> I'm not too familiar with erlang, but what I gathered from the src was
>>>>>> `pread_iolist` function is used when reading anything from the disk. So
>>>>>> I think this might be a corrupt db problem.
>>>>>>
>>>>>> Thanks,
>>>>>> Stephen Bartell
>>>>>
>>>>
>>>
>>
>
