Warning: log write time

After upgrading to 10.2.0.4, we started seeing messages in alert log

*** 2009-10-27 11:12:26.575
Warning: log write time 590ms, size 22KB

Metalink Note 601316.1 describes this issue. LGWR starts producing trace files with this kind of information:

Elapsed times include waiting on following events:

Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 3 0.00 0.00
SQL*Net message from client 3 0.00 0.00
db file sequential read 7080 3.83 196.43
latch: session allocation 1 0.00 0.00
read by other session 2 0.53 0.59
latch free 1 0.00 0.00

*** 2009-10-27 11:12:26.575
Warning: log write time 590ms, size 22KB
*** 2009-10-27 11:12:28.294
Warning: log write time 610ms, size 43KB
*** 2009-10-27 11:12:30.257
Warning: log write time 570ms, size 69KB
*** 2009-10-27 11:12:47.335
Warning: log write time 700ms, size 2213KB
*** 2009-10-27 11:14:02.255
Warning: log write time 560ms, size 1372KB
*** 2009-10-27 11:14:03.104
Warning: log write time 850ms, size 2823KB
*** 2009-10-27 11:16:10.756
Warning: log write time 640ms, size 261KB
*** 2009-10-27 11:16:51.149
Warning: log write time 500ms, size 1703KB
*** 2009-10-27 11:16:51.800
Warning: log write time 650ms, size 3317KB

As per the note

These messages are very much expected in 10.2.0.4 database in case the log write is more than 500 ms.

This is a warning which means that the write process is not as fast as it intented to be. So probably you need to check if the disk is slow or not or for any potential OS causes. If everything looks fine at the hardware level or OS level then you can safely ignore these messages.

The trace file can easily be deleted or truncated.