Redo log switches and waits database freezes

  • From: "Jack van Zanen" <jack@xxxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 20 Nov 2006 22:52:48 +0100

Hi All,



OS: windows 2003 server



I have a database that is running in noarchivelog mode and the log files are
not multiplexed. I have only 2 drives available for oracle so I have put my
redo log files separate from datafiles


This database is for conversion purposes and needs to be as fast as the
hardware allows me.

I am using SQL*loader to load files into this database after which I can do
transformations followed by and extraction to the final system.


I need enabled constraints (mainly check) so direct load is out of the
question I guess.


Now when I load my data After a while all 4 250MB logfiles have status
active and checkpointing  freezes the database. 

But even if it just loads 1 file, leaving just 1 redo log file active and 1
current, and I manually checkpoint the database this takes a long time
during which the database is not responding.


I have searched metalink  and google but have not found anything usefull
relating to this.


I have some of the wait events relating to the logfiles listed here and the
top wait events for this loader session was actually log file sync



9|log file sequential read|15|0.37

9|log file single write|68|1.67

9|log file parallel write|897575|0.75

2|log file switch completion|742|33.74

5|log file sync|896616|0.75



If you need more information please let me know specific which 


Brgds Jack

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