On Thu, Sep 8, 2011 at 8:42 PM, Fujii Masao <masao.fu...@gmail.com> wrote: > Another idea to avoid spinlock contention is save the timestamp in > PgBackendStatus (which contains information for pg_stat_activity). > This enables us to write and read the timestamp without spinlock. > Comments?
That seems like a possibly promising approach, in that each backend could update the information separately, and it's the reader's job to go find the maximum of all those values when needed. So the overhead is (properly, in this case) placed on the reader instead of the writer. But it's a bit tricky, because when the reader wants that maximum, it has to take into account inactive backends that may have committed transactions before exiting, not just the ones that are still connected. -- 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
