On Tue, Oct 27, 2015 at 4:04 PM, Merlin Moncure <mmoncure@xxxxxxxxx> wrote: > On Tue, Oct 27, 2015 at 2:33 PM, Jeff Janes <jeff.janes@xxxxxxxxx> wrote: >> On Mon, Oct 26, 2015 at 8:30 PM, 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. >> >> >> From all the lseeks on the same file, it looks like you are doing a >> sequential scan on a table for the inside of a nested loop. What is the >> query it is running, and what is the execution plan for it? To get that, >> run: > > this smells like thp compaction: drat -- sorry for partial email. check this link: http://structureddata.org/2012/06/18/linux-6-transparent-huge-pages-and-hadoop-workloads/ if that turns out not to be productive, need to check 'perf top', and also rule out problems with individual queries. merlin -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
