Re: number of semaphores and semaphore sets - Mailing list pgsql-docs

On Mon, Mar 21, 2011 at 12:05 PM, Anton Yuzhaninov <citrin@citrin.ru> wrote:
> This page:
> http://www.postgresql.org/docs/9.0/interactive/kernel-resources.html
>
> has formula:
> ceil((max_connections + autovacuum_max_workers) / 16)
>
> for number of semaphore sets (identifiers).
>
> It seems to be wrong (outdated).
>
> Correct formula seems to be
>
> ceil((max_connections + autovacuum_max_workers + 4) / 16)
>
> Semaphore sets created in src/backend/storage/lmgr/proc.c:
> 1. MaxConnections
> 2. autovacuum_max_workers + 1
> 3. NUM_AUXILIARY_PROCS (currently 3)

Yeah, I think you're right.  It appears that nothing material has
changed here since 8.3, so I'm inclined to back-patch this doc fix
back that far.

Barring objections, I'll go change this.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company