Before i used 9.3.5 and servers with ubuntu 12 with 32GB memory.
After upgrade to 9.4.1, with more power server 60GB memory on each in =
wall replication and ubuntu 14, started get db stucks when run multi =
update from resque/sidekiq background workers. resque/sidekiq work via =
pgpool 3.3
Queries can be as simple, update column where primary id =3D id. and =
complex, doesn't metter. usually average connections about less 300, but =
when queries stucks, count connections grow to maximum and i get
LOG: process 16121 still waiting for ShareLock on transaction =
2448707428 after 1000.121 ms
DETAIL: Process holding the lock: 16139. Wait queue: 16121.
LOG: process 16146 still waiting for ExclusiveLock on tuple (665346,11) =
of relation 997395 of database 16455 after 1000.102 ms
DETAIL: Process holding the lock: 16121. Wait queue: 16146.
ERROR: canceling statement due to lock timeout
then
FATAL: sorry, too many clients already
then only restart help, when run restart got this
WARNING: terminating connection because of crash of another server =
process
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.
HINT: In a moment you should be able to reconnect to the database and =
repeat your command.
Current settings,
Database size 190GB
max_connections =3D 400
shared_buffers =3D 13GB
work_mem =3D 19660kB
maintenance_work_mem =3D 2GB
effective_cache_size =3D 40GB
But i played with different, didn't help. On 9.3 all was fine. Nothing =
more in logs.
Also in one day i did pg_repack, on next day db was down with usual =
queries.=
