On Wed, Oct 5, 2011 at 1:48 PM, Kevin Grittner <[email protected]> wrote: > Hamza Bin Sohail <[email protected]> wrote: > >> My postgres version is 8.3.7 > > Why such an old version? Why exclude the available bug fixes? > > http://www.postgresql.org/support/versioning > >>> I am aware that lock contention can be checked with lockstat (and >>> with pg_locks ? ) but I wanted to know if someone can tell me how >>> much contention there would be for this database in a 16-core >>> system vs a 4-core system. I just need a rough idea. > > How many database connections will be used? If more than about > twice the number of cores, you should probably be going through a > transaction-based connection pool. > > With 16 cores, even with a properly configured connection pool, you > will probably be on the edge of where spinlock contention starts > eating significant CPU time. With enough system RAM and proper > tuning the hit should be fairly minor, I think. It really gets bad > at 32 cores, although that is being improved for next year's 9.2 > release.
I think that on write-heavy workloads (like pgbench) we bottleneck on lightweight lock contention around 8 cores. :-( -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
