Hi, I started seeing those errors on Postgresql 10.1 running on Ubuntu 16.04.3 (64GB/8CPU) server. The DB enters recovery mode after that.
2017-11-23 07:20:39 CET::@:[24823]: ERROR: could not attach to dynamic shared area 2017-11-23 07:20:39 CET::@:[24822]: ERROR: could not map dynamic shared memory segment 2017-11-23 07:20:40 CET:192.168.xx,xx(33974):u(at)db:[24209]: ERROR: too many dynamic shared memory segments The errors happen when the parallel execution is enabled and multiple queries are executed simultaneously. If I set the max_parallel_workers_per_gather = 0 the error doesn't occur. The queries are rather big, each executes over 10sec. I see the error when 4 or more queries are started at the same time. my postgresql.conf: max_connections = 100 shared_buffers = 12GB effective_cache_size = 51GB work_mem = 83886kB maintenance_work_mem = 2GB max_wal_size = 8GB min_wal_size = 4GB checkpoint_completion_target = 0.9 wal_buffers = 32MB default_statistics_target = 1000 max_locks_per_transaction = 128 #max_parallel_workers_per_gather = 0 PS. I've posted this question on pgsql-admin distro but didn't get any feedback. -- regards, Jakub Glapa
