On Tue, 27 Oct 2015 11:30:45 +0800 "657985552@xxxxxx" <657985552@xxxxxx> wrote: > Dear sir: > Recently a wired question about postgresql database really bothered me a lot, so i really need your help. Here is the problem, in the most situations the postgre database work very well, Average 3500tps/s per day, the cpu usage of its process is 3%~10% and every query can be responsed in less than 20ms, but sometimes the cpu usages of its process can suddenly grow up to 90%+ , at that time a simple query can cost 2000+ms. ps: My postgresql version is 9.3.5 and the database is oltp server. 9.3.5 is pretty old, you should probably schedule an upgrade. > shared_buffers | 25GB Try setting this to 16GB. It's been a while since I tested on large-memory/high-load systems, but I seem to remember that shared_buffers above 16G could cause these sorts of intermittant stalls. If that doesn't improve the situation, you'll probably need to provide more details, specifically the layout of the table in question, as well as the queries that are active when the problem occurs, and the contents of the pg_locks table when the problem is occurring. -- Bill Moran -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general