Re: SMP-support on PostgreSQL/Cygwin
От | Henshall, Stuart - WCP |
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Тема | Re: SMP-support on PostgreSQL/Cygwin |
Дата | |
Msg-id | E2870D8CE1CCD311BAF50008C71EDE8E01F74813@MAIL_EXCHANGE обсуждение исходный текст |
Ответ на | SMP-support on PostgreSQL/Cygwin ("Markus Wollny" <Markus.Wollny@computec.de>) |
Список | pgsql-cygwin |
Hello, There is no threading in PostgreSQL, it uses a multi process model where each connection has a back end process. All the postmaster does is fork new backends, so unless you are doing a lot of connecting the postmaster shouldn't be doing much. Therefore a transaction will not use more than one processor. However it sounds as if you have multiple connections executing at once, so it may be lock contention or I/O bound. Increasing shared memory buffers may help. - Stuart > -----Original Message----- > From: Markus Wollny [mailto:Markus.Wollny@computec.de] > Sent: 07 March 2002 08:57 > > Hello! > > I've got PostgreSQL 7.2 running on Cygwin on a four-processor Win2K > server. Now I sometimes notice processor time being very unevenly > distributed between processors. When I start I time consuming job, at > the beginning it shows up quite evenly on all four processors. The > taskmanager shows 12 process-instances of postgres.exe running. One of > them however seems to consume quite a lot more processing > power than the > others - I assume that this one is the daemon-postmaster, which spawns > all the other processes. In a later stage of the test-job, > the processor > time on three of the processors seems to be falling, whereas on one of > the four usage remains at a high level. This could indicate that the > postmaster ist running exclusively on this one processor. Hence my > question: Is there no multithreading in this configuration which would > allow for a more evenly distribution of processing time on > all available > processors? > > Greetings, > > Markus >
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