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Hi,
Which process is responsible for updating CONTROL FILE abt
the datafile path, tablespace name and archives info.
I know that SCN is updated by ckpt. But have doubt for the above info
Regards
rakesh
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Originally posted by bang_dba
Hi,
Which process is responsible for updating CONTROL FILE abt
the datafile path, tablespace name
It's server process I guess
no idea about this
-nagarjuna
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I don't think server process is the one who does this....coz when some of the modifications what we do at the mount phase is also reflected in the control file; like when we change the name of the system datafile in the mount phase it is automatically reflected in the control file, during which there is no server proess started.....
I guess Oracle kerner internally writes to the controlfile abt the physical changes.....i am not sure abt this...
Can some experts put light on this ?
sonia
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Originally posted by Sonia
.... in the mount phase it is automatically reflected in the control file, during which there is no server proess started.....
What makes you think there is no server process started when database is mounted? In mount phase, the instance is allready started and functioning - SGA is formed, background processes started, it is only the database files that are not opened yet.
If you check the process scheme (Figure 8-2 in Concepts manual) http://download-west.oracle.com/docs...rocs.htm#18128, it clearly indicates which server processes are responsible for updating control file information: LGWR, CKPT and ARCn. There might be some othere process that interacts with controlfiles that are not indicated on that picture, but those three are the main contributors for controlfile information.
Jurij Modic
ASCII a stupid question, get a stupid ANSI
24 hours in a day .... 24 beer in a case .... coincidence?
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Right... its the ARCn process which does the job. The moment DB is mounted, SGA is formed,Background process starts, LGWR,ARCn starts.
Thanks
PNRDBA
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Originally posted by jmodic
What makes you think there is no server process started when database is mounted? In mount phase, the instance is allready started and functioning - SGA is formed, background processes started, it is only the database files that are not opened yet.
If you check the process scheme (Figure 8-2 in Concepts manual) http://download-west.oracle.com/docs...rocs.htm#18128, it clearly indicates which server processes are responsible for updating control file information: LGWR, CKPT and ARCn. There might be some othere process that interacts with controlfiles that are not indicated on that picture, but those three are the main contributors for controlfile information.
CKPT => updates checkpoint
LGWR => updates about log switches and log sequence numbers
ARCn => writes about the archivelogs
Then, who else updates about the datafile path and their name??? I think it should the be the server process that invokes the session.
Is there anyway to find out which process acts at a particular time and the name of the file???
-nagarjuna
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Nagarjuna,
I agree with you that it is not clear which process writes to controlfiles when you change some datafile or logfile names - that's why I said
There might be some othere process that interact with controlfiles that are not indicated on that picture
. However I'm sure of one thing: It is certainly not session's server process. Those processes never write anything to the database, all of their I/O activities are READs and READs only. I'm also cetain it is not ARCn processes (because there might not be any of them in the instance). I would not rule out neither CKPT nor LGWR to be responsible for this job, as well as maybe DBWR. I'm also positive SMON and PMON have nothing to do with that.
Jurij Modic
ASCII a stupid question, get a stupid ANSI
24 hours in a day .... 24 beer in a case .... coincidence?
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Jmodic,
yeh....a server process gets started as soon as you connect...
sql>connect / as sysdba
sql>startup mount
Is this process also responsible for initializing the SGA and starting other background processes....
And one more thing............is the serverprocess also considered as a background process ?
or is it called as a foreground process ?
regards
sonia
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Originally posted by Sonia
Jmodic,
yeh....a server process gets started as soon as you connect...
sql>connect / as sysdba
sql>startup mount
Is this process also responsible for initializing the SGA and starting other background processes....
Yes, I would say so.
And one more thing............is the serverprocess also considered as a background process ?
or is it called as a foreground process ?
[/B]
No, server process (a process that is opened by RDBMS on behalf of user's application process) is never considered as "background process" in the context of Oracle's process terminology. AFAIK Oracle documentation allways mention only two tipes of processes that are handled by RDBMS on the server side: "background processes" (PMON, SMON, DBWR, LGWR, ......) and "server processes" (processes that handle user requests against the database). I don't remember coming across the term "foreground process" in this context.
Jurij Modic
ASCII a stupid question, get a stupid ANSI
24 hours in a day .... 24 beer in a case .... coincidence?
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