Robert Haas wrote:
> On Mon, Mar 21, 2011 at 12:05 PM, Anton Yuzhaninov <cit...@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 It seems to be wrong (outdated).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.
I have applied the attached patch and backpatched it to 9.0 and 9.1.
--
Bruce Momjian <br...@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ It's impossible for everything to be true. +
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
new file mode 100644
index 5098aad..68ceff1
*** a/doc/src/sgml/runtime.sgml
--- b/doc/src/sgml/runtime.sgml
*************** psql: could not connect to server: No su
*** 604,616 ****
<row>
<entry><varname>SEMMNI</></>
<entry>Maximum number of semaphore identifiers (i.e., sets)</>
! <entry>at least <literal>ceil((max_connections + autovacuum_max_workers) / 16)</literal></>
</row>
<row>
<entry><varname>SEMMNS</></>
<entry>Maximum number of semaphores system-wide</>
! <entry><literal>ceil((max_connections + autovacuum_max_workers) / 16) * 17</literal> plus room for other applications</>
</row>
<row>
--- 604,616 ----
<row>
<entry><varname>SEMMNI</></>
<entry>Maximum number of semaphore identifiers (i.e., sets)</>
! <entry>at least <literal>ceil((max_connections + autovacuum_max_workers + 4) / 16)</literal></>
</row>
<row>
<entry><varname>SEMMNS</></>
<entry>Maximum number of semaphores system-wide</>
! <entry><literal>ceil((max_connections + autovacuum_max_workers + 4) / 16) * 17</literal> plus room for other applications</>
</row>
<row>
*************** psql: could not connect to server: No su
*** 685,691 ****
linkend="sysvipc-parameters">). The parameter <varname>SEMMNI</>
determines the limit on the number of semaphore sets that can
exist on the system at one time. Hence this parameter must be at
! least <literal>ceil((max_connections + autovacuum_max_workers) / 16)</>.
Lowering the number
of allowed connections is a temporary workaround for failures,
which are usually confusingly worded <quote>No space
--- 685,691 ----
linkend="sysvipc-parameters">). The parameter <varname>SEMMNI</>
determines the limit on the number of semaphore sets that can
exist on the system at one time. Hence this parameter must be at
! least <literal>ceil((max_connections + autovacuum_max_workers + 4) / 16)</>.
Lowering the number
of allowed connections is a temporary workaround for failures,
which are usually confusingly worded <quote>No space
--
Sent via pgsql-docs mailing list (pgsql-docs@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-docs
