Hi,

usage of semaphores depends on the number of current connections
(not the possible one).

Have a look at: http://sapdb.2scale.net/moin.cgi/DiagnosingSharedResources

Setting this value as mentioned from Markus D�hr we decreased our
cpu usage from avg. 50% to 20% (again thanks to Markus ;-) ).


bye GERD




-----Urspr�ngliche Nachricht-----
Von: Patrick Buchinger [mailto:[EMAIL PROTECTED]
Gesendet: Dienstag, 11. November 2003 11:06
An: SAPDB Mailinglist
Betreff: RE: !! db crash !! "cannot create semaphore" ????


hello!

since we have the same problem (it occured after i was installing a 5th
database instance on our server) i will also try adding this line to
/etc/sysctl.conf.

but i'm courious what exactly does this line do? could i run into
problems when i set these values too high?

thank you,

patrick buchinger

ps: we are running red hat 9.0


> Hi again,
>
> > the command tells me:
> >
> > sysctl -a | grep sem
> > kernel.sem = 250        32000   32      128
> >
> > seems you have a lot more ;-)
> >
> > What exactly does this mean (in combination with sapdb), and
> > how can I increase this value ?kernel.sem=4096 512000 1600 2048
>
> The definition is
>
> kernel.sem: max_sem_per_id max_sem_total max_ops_sem_call max_sem_ids
>
> We use the SuSE provided suse-sapinit.rpm to change the parameters at
> bootup. For quickly changing this:
>
> - edit /etc/sysctl.conf
> - add
>
>       kernel.sem=4096 512000 1600 2048
>
>   without quotation marks and the like
> - execute
>
>       # sysctl -p /etc/sysctl.conf
>
> If you then have a look at the parameter again via
>
>       # sysctl -a | grep sem
>
> you'll see that is has changed.
>
> The RPM I talked about will just add the call to sysctl to the startup
> scripts.
>
>
> Hope this helps :-)
>
>
> Greetz,
>
>
> SIEGENIA-AUBI KG
> Informationswesen
>
> i.A.
>
> Markus D�hr
> SAP-CC/BC, SAPDB-DBA
>
> Tel.:  +49 6503 917-152
> Fax:   +49 6503 917-7152
> E-Mail: [EMAIL PROTECTED]
> Internet: http://www.siegenia-aubi.com
>


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