The session is waiting for a buffer to be written. The write is caused by normal aging or a cross instance call.
A user wants to modify a block that is part of DBWR’s current write batch. When DBWR grabs buffers to write, it marks them as 'being written'. All the collected buffers are then written to disk. The wait 'write complete waits' implies we wanted a buffer while this flag was set. The flags are cleared as each buffer is written.
The rest of the information in this section is only valid for this metric when it appears in either the Enterprise Manager Grid Control or the Enterprise Manager Database Control (if applicable).
The following table shows how often the metric's value is collected and compared against the default thresholds. The 'Consecutive Number of Occurrences Preceding Notification' column indicates the consecutive number of times the comparison against thresholds should hold TRUE before an alert is generated.
|
Target Version |
Evaluation and Collection Frequency |
Upload Frequency |
Operator |
Default Warning Threshold |
Default Critical Threshold |
Consecutive Number of Occurrences Preceding Notification |
Alert Text |
|
pre-10g |
Every Minute |
After Every Sample |
> |
20 |
Not Defined |
3 |
%value%%% of service time is spent waiting on the 'write complete waits' event. |
(DeltaWriteCompleteWaitsTime/DeltaServiceTime)*100 where:
DeltaWriteCompleteWaitsTime: difference of 'sum of time waited for sessions of foreground processes on the 'write complete waits' event' between sample end and start
DeltaServiceTime: difference of 'sum of time waited for sessions of foreground processes on events not in IdleEvents + sum of 'CPU used when call started' for sessions of foreground processes' between sample end and start
See Idle Events
Multiple DBWRs, ASYNC_IO and/or increasing the size of the buffer cache may help reduce waits.
Related Topics
About Alerts
About the Metric Detail Page
Editing Thresholds
Understanding Line Charts
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