This metric represents the percentage of statement executions that do not require a corresponding parse. A perfect system would parse all statements once and then execute the parsed statement over and over without reparsing. This ratio provides an indication as to how often the application is parsing statements as compared to their overall execution rate. A higher number is better.
This test checks the percentage of executes that do not require parses. If the value is less than or equal to the threshold values specified by the threshold arguments, and the number of occurrences exceeds the value specified in the "Number of Occurrences" parameter, then a warning or critical alert is generated.
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 5 Minutes |
After Every Sample |
< |
Not Defined |
Not Defined |
2 |
Only %value%%% of executes are performed without parses. |
|
Target Version |
Server Evaluation Frequency |
Collection Frequency |
Upload Frequency |
Operator |
Default Warning Threshold |
Default Critical Threshold |
Consecutive Number of Occurrences Preceding Notification |
Alert Text |
|
10.1.0.x; 10.2.0.x; 11.1.0.x; 11.2.0.x |
Every Minute |
Not Defined |
After Every Sample |
< |
Not Defined |
Not Defined |
2 |
Generated By Database Server |
((DeltaExecuteCount - (DeltaParseCountTotal)) / DeltaExecuteCount) * 100 where:
DeltaParseCountTotal: difference in 'select value from v$sysstat where name='parse count (total)'' between sample end and start
DeltaExecuteCount: difference in 'select value from v$sysstat where name='execute count'' between sample end and start
An execute to parse ratio of less than 70% indicates that the application may be parsing statements more often than it should. Reparsing the statement, even if it is a soft parse, requires a network round trip from the application to the database, as well as requiring the processing time to locate the previously compiled statement in the cache. Reducing network round trips and unnecessary processing improves application performance.
Use the Top Sessions page sorted by Parses to identify the sessions responsible for the bulk of the parse activity within the database. Start with these sessions to determine whether the application could be modified to make more efficient use of its cursors.
Related Topics
About Alerts
About the Metric Detail Page
Editing Thresholds
Understanding Line Charts
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