log file sync

I'm experiencing substantial waits on log file events, as seen below:

                                    Time Waited  % Time
Wait Event                                (min)  Waited Waits (k) % Waits


----------------------------------- ----------- ------- --------- -------

log file sync                               538   55.94      1042   30.31
db file sequential read                     169   17.56      1170   34.05
log file parallel write                     123   12.82       989   28.79
db file parallel write                       95    9.90        35    1.03

From this, it appears that log file sync wait time is about 4-5 times log file parallel write time. I've been looking at some of the advice on Steve Adams' IXOra site, and it seems that my "sync cost" is thus around 4, and I should probably have a smaller log buffer size. But when I run his lgwr_stats script, I get the following results:

    Average Log
     Write Size

           2048

     Background
 Write Theshold

          87552

Sync Cost Ratio

           1.13

Which indicates a much lower sync cost. I realize this is not a "IXOra scripts forum", but which is the proper sync cost, and does my log buffer need to be smaller? It is currently 256K.

--Terry
Received on Sat Feb 23 2002 - 14:37:13 CST