Postgresql error "pg_ctl stop" is invoked after a "postmaster -i &" invocation

Reini Urban rurban@x-ray.at
Thu Dec 9 14:07:00 GMT 2004


Carlo Florendo schrieb:
> I invoked:
> 
> "postmaster -i -D /var/postgresql/data  &"
> 
> and was able to start and connect to my database. Since the process was 
> made to run on the background, I wanted a way to stop it without doing a 
> "kill -9".  Thus, on another instance of my shell, I invoked :
> 
> "pg_ctl stop -D /var/postgresql/data"
> 
> Postgres says it was unsuccessful in shutting down the database.   
> However, doing a "ps" revealed that no postgres processes were running.
> 
> I then tried to restart the DB once again with:
> 
> "postmaster -i -D /var/postgresql/data  &"
> 
> This time, I got this errror:
> 
> $ postmaster -i -D /var/postgresql/data &
> FATAL:  could not create semaphores: No space left on device
> DETAIL:  Failed system call was semget(5432004, 17, 03600).
> HINT:  This error does *not* mean that you have run out of disk space.
>        It occurs when either the system limit for the maximum number of 
> semaphore sets (SEMMNI), or the system wide maximum number of semaphores 
> (SEMMNS), would be exceeded.  You need to raise the respective kernel 
> parameter.  Alternatively, reduce PostgreSQL's consumption of semaphores 
> by reducing its max_connections parameter (currently 40).
>        The PostgreSQL documentation contains more information about 
> configuring your system for PostgreSQL.
> 
> 
> I have a lot of diskspace.  Doing a "df" revealed:

Now the tricky part:
Did you actually read what the error message told you?

Honestly, I know of no other POSIX or Windows app which explains such a 
basic error in such helpful details. And I thought postgresql is already 
  ready for the dummy mode with the new windows port.

max_connections=40 is a bit high and your SEMMNS are way too low for 40.
5 are recommended for a busy system.

$ nano /etc/cygserver.conf
There you can edit the explained kernel params.

> $ df
...
-- 
Reini Urban
http://xarch.tu-graz.ac.at/home/rurban/

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