Re: Role of ORACLE_SID?

Hi from Paris

to be more precise, setting ORACLE_SID has no means outside of the server machine. This variable is used, in conjunction with value for ORACLE_HOME, to get the SGA memory adress, in order to attach the shadow process to shared memory.

Using SQL*Net, this task is done by the listener, which has to start the shadow process and attach it to SGA.

So, there is no reason to set ORACLE_SID on client machines...

"Frank" <fvanbortel_at_netscape.net> a écrit dans le message de news:3ECD1E54.3030105_at_netscape.net...
> Volker Hetzer wrote:
> > Hi!
> > I've been debugging a log on problem for the last few days and I think
I'm
> > in the process of finding the error in my idea of how the oracle
connection
> > is established.
> > So, can anybody explain to me the role of the environment variable
ORACLE_SID
> > in a scenario where the client sits on a different machine from the db
server?
> >
> > I had assumed, when I set ORACLE_SID to the Db SID then sqlplus would,
> > when called "sqlplus name/passwd" check the environment for the SID,
> > consult tnsnames on where to find a db with that sid and then connect to
it.
>
> Close, but no tnsnames (or LDAP, or HOSTS, or whatever is defined in
> sqlnet.ora):
>
> D:\oracle\817\bin>set ORACLE_SID=web920
> D:\oracle\817\bin>sqlplus system/manager
> SQL*Plus: Release 8.1.7.0.0 - Production on Thu May 22 20:52:33 2003
> (c) Copyright 2000 Oracle Corporation. All rights reserved.
>
> ERROR:
> ORA-12560: TNS:protocol adapter error
> Enter user-name:
> D:\oracle\817\bin>type sqlnet.log
>
> ***********************************************************************
> Fatal NI connect error 12560, connecting to:
>
>

(DESCRIPTION=(ADDRESS=(PROTOCOL=BEQ)(PROGRAM=oracle)(ARGV0=oracleweb920)(ARG S='
>

(DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))'))(CONNECT_DATA=(SID=web92 0)(C
>

ID=(PROGRAM=D:\oracle\817\bin\SQLPLUS.EXE)(HOST=CS-FRANK02)(USER=frankbo))))
>
> VERSION INFORMATION:
> TNS for 32-bit Windows: Version 8.1.7.4.0 - Production
> Oracle Bequeath NT Protocol Adapter for 32-bit Windows: Version
> 8.1.7.4.0 - Production
>
> What happens is that the bequeth protocol kicks in - the only protocol
> that does *not* need a listener, because it communicates directly to
> the program stack.
> So, it does not network, and cannot be used for remote connections.
>
> The other side is, that the @networkDbName stuff is actually an alias.
> It's perfectly ok to use: scott/tiger_at_bowie, where bowie is an alias
> for an instance with a sid of jimmy:
> BOWIE.CS.NL =
> (DESCRIPTION =
> (ADDRESS_LIST =
> (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.200)(PORT = 1521))
> )
> (CONNECT_DATA =
> (SID = JIMMY)
> )
> )
>
> Hth,
> --
> Regards, Frank van Bortel
>
Received on Fri May 23 2003 - 10:35:53 CDT