Hi I have the problem that on our servers it happens regularly under a certain workload (several times per minute) that all backend processes get a SIGUSR1 and spend several seconds in ProcessCatchupEvent(). At 100-200 connections (most of them idle) this causes the system load to skyrocket. I am not really familiar with the code but my wild guess is that the processes spend most of their time waiting for spinlocks. We have reduced the number of connections as much as possible for now but it still makes up for roughly 50% of the total CPU time. Has anyone experienced a similar problem? I can reproduce the issue on a test system with production data but it is not so easy to pinpoint what exactly causes the problem. The queries are basically tsearch2 full text searches over moderately big tables (~35GB). The queries are performed by functions which aggregate data from partitions in temporary tables, cache some data, and perform calculations before returning it to the user. The PostgreSQL version is 8.3.12, the test server has 8 amd64 cores and 16GB of ram. I experimented with shared_buffers between 1GB and 4GB but it doesn't make much of a difference. Disk IO doesn't seem to be an issue here. Regards, Julian v. Bock -- Julian v. Bock Projektleitung Software-Entwicklung OpenIT GmbH Tel +49 211 239 577-0 In der Steele 33a-41 Fax +49 211 239 577-10 D-40599 DÃsseldorf http://www.openit.de ________________________________________________________________ HRB 38815 Amtsgericht DÃsseldorf USt-Id DE 812951861 GeschÃftsfÃhrer: Oliver Haakert, Maurice Kemmann -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
