Dzmitry wrote: > On 8/19/13 11:36 AM, "Stéphane Schildknecht" <stephane.schildknecht@xxxxxxxxxxxxx> wrote: >> Le 19/08/2013 10:07, Dzmitry a écrit : >>> 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 [...] >>> >>> My DB size is not very big 169GB. >>> >>> Anyone know how can I get rid of DB crash ? >> 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. > 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 :( You can check by examining /var/log/messages to see if the OOM killer is at fault, which is highly likely. The OOM killer uses heuristics, so it does the wrong thing occasionally. The documentation is helpful: http://www.postgresql.org/docs/9.2/static/kernel-resources.html#LINUX-MEMORY-OVERCOMMIT Yours, Laurenz Albe -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
