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Your instance has spent much of its In Oracle time waiting for the Redo Log.
Description
| |
What to do
next
|
Perform one of
the following options:
n Examine the related
Oracle events (lower area), Redo Activity (upper area), to determine the problem
type in the Statistics workspace.
n Examine high Redo Log
Buffer Wait statements in the Activity workspace.
|
Advice
|
Use any one of
the typical problem scenarios described below.
n If the log buffer size
is too small, this usually results in long waits for the Log Buffer Space
event.
Consider
increasing the Log_buffer parameter.
n If the log buffer size
is too big, this usually results in a low number of user commits, high redo
wastage statistics, and long waits for the Log File Sync
event.
Consider
decreasing the Log_buffer parameter and/or the hidden LOG_I/O_SIZE
parameter.
n If there are too many
commits, this usually results in long waits for the Log File Sync event and the
number of user commits is very high.
Consider
changing the application flow and logic (by decreasing the commit frequency or
using bulk commits [resulting in larger transactions]).
n If the LGWR is too slow,
check whether Log File Sync is still the dominant event. This may be due to high
values for Log File Parallel Write, or because there are not many commits. This
may mean that the LGWR is underperforming.
Consider moving
the log file to a faster, dedicated device.
Whenever the
Log Buffer Space and Log File Sync events occur together, consider changing the
hidden LOG_I/O_SIZE parameter.
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