On Mon, Jun 13, 2011 at 10:29 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Stefan Kaltenbrunner <ste...@kaltenbrunner.cc> writes: >> On 06/12/2011 11:39 PM, Robert Haas wrote: >>> Profiling reveals that the system spends enormous amounts of CPU time >>> in s_lock. > >> just to reiterate that with numbers - at 160 threads with both patches >> applied the profile looks like: > >> samples % image name symbol name >> 828794 75.8662 postgres s_lock > > Do you know exactly which spinlocks are being contended on here? > The next few entries > >> 51672 4.7300 postgres LWLockAcquire >> 51145 4.6817 postgres LWLockRelease >> 17636 1.6144 postgres GetSnapshotData > > suggest that it might be the ProcArrayLock as a result of a huge amount > of snapshot-fetching, but this is very weak evidence for that theory.
I don't know for sure what is happening on Stefan's system, but I did post the results of some research on this exact topic in my original post. -- 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
