This latch protects the allocation of memory from the shared pool.
If there is contention on this latch, it is often an indication that the shared pool is fragmented.
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 'latch: shared pool' event. |
(DeltaLatchSharedPoolTime/DeltaServiceTime)*100 where:
DeltaLatchSharedPoolTime: difference of 'sum of time waited for sessions of foreground processes on the 'latch: shared pool' 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
Shared pool latch contention is often an indication of high hard parsing usually caused by the use of literal values in SQL statements. These statements could otherwise be shared if bind variables were used.
Prior to Oracle Server release 8.1.6, shared pool fragmentation could be acerbated by a shared pool that was too large. Reducing the size of the shared pool would reduce the contention for this latch.
For Oracle Server release 8.1.6 and later, there should be very little shared pool latch contention. If there is, it is probably a symptom of an application using literals. One possible solution is to use the init.ora parameter
Related Topics
About Alerts
About the Metric Detail Page
Editing Thresholds
Understanding Line Charts
Copyright © 1996, 2009, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its affiliates.
Other names may be trademarks of their respective owners.