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Re: Oracle 10g dedicated server how to change to shared mode

From: Rauf Sarwar <rs_arwar_at_hotmail.com>
Date: 13 Jan 2005 09:57:24 -0800
Message-ID: <1105639044.109499.144870@z14g2000cwz.googlegroups.com>

Holger Baer wrote:
> Ed Stevens wrote:
> > On 12 Jan 2005 19:12:39 -0800, evoradba_at_yahoo.ca (Maria) wrote:
> >
> >
> >>Hello
> >>
> >>I have installed Oracle 10g on solaris back in August then to test
we
> >>decided to change to dedicaded mode. Now we can't connect from any
> >>other server, keep getting this error message
> >>SQL*Plus: Release 10.1.0.3.0 - Production on
> >>ERROR:
> >>ORA-12500: TNS:listener failed to start a dedicated server process
> >>
> >>The thing when I do a tnsping to this instance from any other
server
> >>its fine?
> >
> > I presume that was not meant as a question. ;-)
> >
> > You need to understand that TNSPING only proves that you have basic
> > network connectivity and that the listener recognizes the service
you
> > are TNSPINGing. You can put a reference to MYSID in the
listener.ora
> > file and succesfully TNSPING MYSID, without even having created a
> > database MYSID. It's like calling the post office and asking if
they
> > would try to deliver a letter to 123 Elm St. If they say 'yes' it
> > proves you can contact the post office and they think they know
where
> > 123 Elm St. is. It doesn't prove that there actually is such a
> > location.
> >
>
> Ed,
>
> this really nice explanation is unfortunately slightly wrong. When
> you tnsping, the listener doesn't really care if there is such a
service.
> (I tested just with 9.2 on windows)
>
> To keep the analogy: It's like calling the post office and asking if
they
> would try to deliver a letter to 123 Elm St. If they say 'yes' it
proves
> that there was a post office ( or someone who likes a good laugh
> just as everybody else ;-) ). And if you send them something, and if
they
> still are there, they will start looking if they can actually deliver
> what you sent.
>

Holger, You are correct in saying that listener does not care if the sid/service_name exists or not that is sent in the connect descriptor. However, If you don't send in the sid/service_name in the connect descriptor, listener still acknowledges your ping.

C:\>tnsping
(description=(address=(protocol=tcp)(host=rasa)(port=1521)))

TNS Ping Utility for 32-bit Windows: Version 9.2.0.5.0 - Production on 13-JAN-2005 17:45:51 Copyright (c) 1997 Oracle Corporation. All rights reserved.

Attempting to contact
(description=(address=(protocol=tcp)(host=rasa)(port=1521))) OK (20 msec)

So continuing with the analogy,
It's like calling the post office and asking if they are located on 123 Elm street and are currently open. That's it. Whether they can deliver a letter to the address is a separate thing. So listener does actually behave like the postal service :>).

Tnsping is the subset of Ping. Ping just tells you if the IP address is valid and the machine is up and running... it does not tell you whether you can access it. Tnsping will tell you if there is an Oracle listener on that machine listening on port xxxx using protocol yyyy... It does not tell you anything beyond that.

Regards
/Rauf Received on Thu Jan 13 2005 - 11:57:24 CST

Original text of this message

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