On Nov 22, 2007 9:09 AM, giuseppe-r@xxxxxxxxxx <giuseppe-r@xxxxxxxxxx> wrote: > I'm doing tests on various Database and in particular I'm running a > comparison between Oracle 10g and Postgres 8.1 on a dedicated server As Bill said, do not publish any part of the Oracle result anywhere. > with 2 processors Dual-Core AMD Opteron 2218 2.6 GHz, 4GB of memory > and Debian GNU / Linux version 2.6.18-5. Performance is very similar up > to 30 users, but from 40 onwards with Postgres fall quickly. That is > not what happens with Oracle that comes to 600 users. Can you help me > with the tuning ? I'm not sure which TPC-C kit you're using, but you should probably use DBT-2. http://sourceforge.net/project/showfiles.php?group_id=52479&package_id=54389&release_id=485705 http://oss.oracle.com/projects/olt/ As for parameters, I'd start with: - Make sure wal and data are split and their RAIDs (if any) are configured properly. shared_buffers = 98304 (this may need to stay at your current one depending on the cost of checkpoints) max_prepared_transactions = 5 (this doesn't have anything to do with what it sounds like) max_fsm_relations = 1000 bgwriter_delay = 500 wal_sync_method = open_sync (or try open_datasync) wal_buffers = 256 checkpoint_segments = 256 (if you have the space) checkpoint_timeout = 1800 checkpoint_warning = 1740 effective_cache_size = 346030 default_statistics_target = 100 I'm not sure whether DBT-2 supports it out-of-the-box, but you should also look at changing default_transaction_isolation to serializable. Keep in mind that DBT-2 has several bugs in it. Though, I'm not sure whether Oracle fixed them on their version either. It also looks like you have fsync turned off, which means commits are not guaranteed (unlike your Oracle configuration). If you want apples-to-apples, you need to turn fsync on. -- Jonah H. Harris, Sr. Software Architect | phone: 732.331.1324 EnterpriseDB Corporation | fax: 732.331.1301 499 Thornall Street, 2nd Floor | jonah.harris@xxxxxxxxxxxxxxxx Edison, NJ 08837 | http://www.enterprisedb.com/ ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
