Hello ! I am running PostgreSQL 8.3.5 on a linux machine (Ubuntu 10.04). Sometimes it happens that connecting to the database fails with error : FATAL: semctl(360458, 3, SETVAL, 0) failed: Invalid argument (PGError) If i restart postgres the problem gets "fixed". It doesn't matter how do i connect to the database : i saw this happening from psql, from jdbc, and from ruby. The pgsql configuration is the default one : i have changed only listen_addresses and the port. However, the machine is configured with some pretty large values for POSIX queues: fs.mqueue.msgsize_max=2621440 fs.mqueue.msg_max=10240 fs.mqueue.queues_max=10240 Also, the user is unlimited in regards to queues in /etc/security/limits/conf : am hard msgqueue unlimited These are needed for another application running on the same machine (which performs some heavy communication via POSIX queues). I am not sure whether this can interfere with the semaphores used by postgres ... Does the situation described above ring any bell for anyone? Any suggestion about how to analyse deeper the problem ? I am also aware that the error happened also on another machine (Fedora linux) that has the same mqueue settings. Best regards, Adrian Maier PS: Here is an example log file : LOG: database system was shut down at 2010-11-04 16:50:35 EET LOG: database system is ready to accept connections LOG: autovacuum launcher started FATAL: semctl(360458, 6, SETVAL, 0) failed: Invalid argument FATAL: semctl(360458, 3, SETVAL, 0) failed: Invalid argument FATAL: semctl(360458, 2, SETVAL, 0) failed: Invalid argument LOG: received smart shutdown request LOG: autovacuum launcher shutting down LOG: shutting down LOG: database system is shut down LOG: semctl(327689, 0, IPC_RMID, ...) failed: Invalid argument LOG: semctl(360458, 0, IPC_RMID, ...) failed: Invalid argument -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general