From: | "James Pang (chaolpan)" <chaolpan(at)cisco(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | "pgsql-admin(at)lists(dot)postgresql(dot)org" <pgsql-admin(at)lists(dot)postgresql(dot)org> |
Subject: | RE: multiple sessions to create index in parallel support |
Date: | 2022-06-22 14:15:34 |
Message-ID: | PH0PR11MB519109D62D6D03BA59BD4739D6B29@PH0PR11MB5191.namprd11.prod.outlook.com |
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Lists: | pgsql-admin |
Sorry for confusion. This time, I add "max_parallel_workers"=32 , "max_parallel_maintenance_workers"=32 , "max_workers_process"=64 to postgresql.conf, and restart database. This time, both session runs in parallel now. Last several tests only got these parameter changes by set max_parallell_workers... in session level , for each session , only 1 session parallel creating index.
James
-----Original Message-----
From: James Pang (chaolpan)
Sent: Wednesday, June 22, 2022 9:34 AM
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-admin(at)lists(dot)postgresql(dot)org
Subject: RE: multiple sessions to create index in parallel support
All max_workers_process got increased to 32 before creating index. The 2 session try to create index on totally separate large tables(40gb) , either one in 8 parallel workers, but not both.
James
-----Original Message-----
From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Sent: Tuesday, June 21, 2022 11:04 PM
To: James Pang (chaolpan) <chaolpan(at)cisco(dot)com>
Cc: pgsql-admin(at)lists(dot)postgresql(dot)org
Subject: Re: multiple sessions to create index in parallel support
"James Pang (chaolpan)" <chaolpan(at)cisco(dot)com> writes:
> Max_parallel_workers and max_parallel_maintenance_workers both equal to 32, one session create one index in a large table show parallel 8 workers, the other session creating one index in another separate table always in serial. Even increase max_parallel_worers and max_parallel_maintenance_workers to 64, still show one is parallel 8 workers, the other is done in serial.
Hmm, what about max_worker_processes ? That's an independent limit.
regards, tom lane
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