RE: 'redo copy' latch

From: Naveen Nahata <naveen_nahata_at_mindtree.com>
Date: Tue, 22 Oct 2002 21:38:24 -0800
Message-ID: <F001.004F08F5.20021022213824@fatcity.com>

Thanx for the reply. Version is 8.0.6.1.0 on WindowsNT

What is the parameter that defines the no. of 'redo copy latches'. Is it decided by Oracle or DBA has the control over it?

Regards
Naveen

-----Original Message-----
Sent: Wednesday, October 23, 2002 4:34 AM To: Multiple recipients of list ORACLE-L

Naveen:

   What Oracle version are you using?
   The LGWR behavior has changed in version 8i.

   As far as I know (and you can read many papers about it in ixora site), the redo copy latches are requested as immediate (no-wait mode), all of them except the last one. The last one is requested in wait mode.

   As you have many redo copy latches Oracle does not waste any time sleeping for one of them, he tries the other ones first and sleep for the last one.

   BUT this is the LGWR behavior up to version 7.3.4, I think that in newer versions (8i ....9i) it has changed a lot, and I believe that Oracle does not wait for the redo copy latches any longer.    

   I hope some Guru could confirm this and explain the new behavior in detail.

HTH
Greetings
Diego Cutrone    

Hi All,

When looking at v$latch it gave me the following stats for 'redo copy'

GETS: 35
MISSES: 21
IMMEDIATE_GETS: 326975
IMMEDIATE_MISSES: 65 according to my understanding 'redo copy' is required when the process writes
to the redo buffer. am i right?

if i'm right, why is it that this latch is requested with a no-wait option(evident from high IMMEDIATE_GETS as compared to GETS).

regards
Naveen
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Author: Naveen Nahata
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Author: Naveen Nahata
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To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). Received on Wed Oct 23 2002 - 00:38:24 CDT