Tom, Are you having a lot of control file writes precipitated by a small redo log file as compared to the redo size/rate and a large number of datafiles? You should be able to check this from the number of datafiles and redo log file/rate and have a feeling for amount of checkpoint I/O by comparing V$SYSSTAT's 'physical writes non checkpoint' to 'physical writes'. The former should lag the latter by a a very small percentage.... Regards, John Kanagaraj <>< DB Soft Inc Phone: 408-970-7002 (W) Co-Author: Oracle Database 10g Insider Solutions http://www.amazon.com/exec/obidos/tg/detail/-/0672327910/ ** The opinions and facts contained in this message are entirely mine and do not reflect those of my employer or customers ** -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Steve Adams Sent: Monday, February 27, 2006 4:56 PM To: pele_00_2000@xxxxxxxxx Cc: oracle-l@xxxxxxxxxxxxx Subject: Re: High waits/Timeouts - log file parallel write Hi Tom, The 'log file parallel write' waits affect LGWR only. They do not affect the performance of user processes directly (although they do impact somewhat on your 'log file sync' wait duration). The number of timeouts is influenced by your use of asynchronous I/O and by how often LGWR is posted by user processes. It is not a useful indicator of performance problems. I think you should be more concerned about the 'control file parallel write' waits that are probably affecting user processes directly. @ Regards, @ Steve Adams @ http://www.ixora.com.au/ - For DBAs @ http://www.christianity.net.au/ - For all TP wrote: > Hello all, > > I seeing high Waits, Timeouts from one the problem instance. > > Top 5 Timed Events > ~~~~~~~~~~~~~~~~~~ > % Total > Event > Waits Time (s) Ela Time > -------------------------------------------- > ------------ ----------- -------- > CPU time > 8 40.51 > control file parallel write > 642 5 25.56 > db file sequential read > 343 2 9.40 > log file parallel write > 9,697 2 7.99 > log file sync > 425 1 5.69 > -- //www.freelists.org/webpage/oracle-l