Re: postgres crashes on insert in 40 different threads

I don't think it's the case. I am using newrelic for monitoring my DB
servers(I have one master and 2 slaves - all use the same configuration) -
memory is not going above 12.5GB, so I have a good reserve, also I don't
see any swapping there :(

Thanks,
Dzmitry

On 8/19/13 11:36 AM, "Stéphane Schildknecht"
<stephane(dot)schildknecht(at)postgresql(dot)fr> wrote:

>Le 19/08/2013 10:07, Dzmitry a écrit :
>> Hey folks,
>> I have postgres server running on ubuntu 12,Intel Xeon 8 CPUs 29 GB
>>RAM.
>> With following settings:
>> max_connections = 550
>> shared_buffers = 12GB
>> temp_buffers = 8MB
>> max_prepared_transactions = 0
>> work_mem = 50MB
>> maintenance_work_mem = 1GB
>> fsync = on
>> wal_buffers = 16MB
>> commit_delay = 50
>> commit_siblings = 7
>> checkpoint_segments = 32
>> checkpoint_completion_target = 0.9
>> effective_cache_size = 22GB
>> autovacuum = on
>> autovacuum_vacuum_threshold = 1800
>> autovacuum_analyze_threshold = 900
>>
>> I am doing a lot of writes to DB in 40 different threads ­ so every
>>thread
>> check if record exists ­ if not => insert record, if exists => update
>>record.
>> During this update, my disk IO almost always ­ 100% and sometimes it
>>crash my
>> DB with following message:
>>
>> 2013-08-19 03:18:00 UTC LOG: checkpointer process (PID 28354) was
>>terminated
>> by signal 9: Killed
>> 2013-08-19 03:18:00 UTC LOG: terminating any other active server
>>processes
>> 2013-08-19 03:18:00 UTC WARNING: terminating connection because of
>>crash of
>> another server process
>> 2013-08-19 03:18:00 UTC DETAIL: The postmaster has commanded this
>>server
>> process to roll back the current transaction and exit, because another
>>server
>> process exited abnormally and possibly corrupted shared memory.
>> 2013-08-19 03:18:00 UTC HINT: In a moment you should be able to
>>reconnect to
>> the database and repeat your command.
>> 2013-08-19 03:18:00 UTC WARNING: terminating connection because of
>>crash of
>> another server process
>> 2013-08-19 03:18:00 UTC DETAIL: The postmaster has commanded this
>>server
>> process to roll back the current transaction and exit, because another
>>server
>> process exited abnormally and possibly corrupted shared memory.
>> 2013-08-19 03:18:00 UTC HINT: In a moment you should be able to
>>reconnect to
>> the database and repeat your command.
>> 2013-08-19 03:18:00 UTC WARNING: terminating connection because of
>>crash of
>> another server process
>> 2013-08-19 03:18:00 UTC DETAIL: The postmaster has commanded this
>>server
>> process to roll back the current transaction and exit, because another
>>server
>> process exited abnormally and possibly corrupted shared memory.
>>
>> My DB size is not very big ­ 169GB.
>>
>> Anyone know how can I get rid of DB crash ?
>>
>>
>> Thanks,
>> Dzmitry
>>
>
>The fact that the checkpointer was killed -9 let me think the OOMKiller
>has
>detected you were out of memory.
>
>Could that be the case?
>
>12GB of shared_buffers on a 29Gb box is too high. You should try to lower
>that
>value to 6GB, for instance.
>550*50MB, that is 27GB of RAM that PostgreSQL could try to adress.
>
>I can imagine your system is swapping a lot, and you exhaust swap memory
>before
>crash.
>
>Regards,
>
>--
>Stéphane Schildknecht
>Loxodata - Conseil, expertise et formations
>
>
>
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