RE: log file sync wait

From: Gogala, Mladen <MGogala_at_oxhp.com>
Date: Mon, 05 May 2003 09:17:04 -0800
Message-ID: <F001.0058FB80.20030505091704@fatcity.com>

We're not talking about "_disable_logging", an ancient parameter for cheating on benchmarks, are we? I've tried that and if anything happens, the database doesn't come up. Other then the possibility that you might lose all your data, everything works fine and the database is flying like a greased lightning.

Mladen Gogala
Oracle DBA
Phone:(203) 459-6855
Email:mgogala_at_oxhp.com

-----Original Message-----
Sent: Monday, May 05, 2003 5:07 AM
To: Multiple recipients of list ORACLE-L

Ganesh:

Not very true. Slower log files with bigger log buffers are the main cause for log file sync waits. THis typically happens during a transaction end, either commit or rollback will make others wait for the log file sync.

To reduce this, you can keep the redo logs in the fastest disk, use no-logging wherever you can, reduce the commits,tune the sessions/processes parameter. And also there is an underscore parameter which will completely eliminate the log_file_sync waits. But that is against the Oracle's implementation of the ACID property in the transactional database system. You can use them during batch loads, benchmarks, _non_ production systems and test systems. But then the committed transactions are not necessarily committed transactions.

• ganesh_raja_at_non.agilent.com wrote:
  > Ur Log file sync wait is mainly because your Log Buffer is small and
  > every time Logwr Writes the redo into the Redo Logs your apps are
  > waiting for the sync to complete.
  >
  > Run Your Lgwr in Parallel using IO Slaves or use Async_IO parameter
  > ro control it from OS.
  > Increase the size of your LOGBuffer so that the ur App does not wait
  > for the syncs..
  >
  > HTH
  >
  > Best Regards,
  > Ganesh R
  

  ---

Have a nice day !!

---

Best Regards,
K Gopalakrishnan,
Bangalore, INDIA.

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Received on Mon May 05 2003 - 12:17:04 CDT