On Tue, Sep 2, 2014 at 11:02 PM, Xiaoyulei <xiaoyu...@huawei.com> wrote: > benchmarSQL has about half reads. So I think it should be effective. > > I don't think BufFreelistLock take much time, it just get a buffer from list. > It should be very fast.
You're wrong. That list is usually empty right now; so it does a linear scan of the buffer pool looking for a good eviction candidate. > The test server has 2 CPUs and 12 cores in each CPU. 24 processor totally. > CPU Idle time is over 50%. IO only 10%(data is in SSD) > > I perf one process of pg. The hot spot is hash search. Attachment is perf > data file. I think you need to pass -g to perf so that you get a call-graph profile. Then you should be able to expand the entry for hash_search_with_hash_value() and see what's calling it. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
