Oracle keeps note of which rows are locked by which transaction in an area at the top of each data block known as the 'interested transaction list'. The number of ITL slots in any block in an object is controlled by the INITRANS and MAXTRANS attributes. INITRANS is the number of slots initially created in a block when it is first used, while MAXTRANS places an upper bound on the number of entries allowed. Each transaction which wants to modify a block requires a slot in this 'ITL' list in the block.
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 'enqueue: TX mode 4, Transaction - allocate ITL entry' event. |
(DeltaEnqueueAllocITLTime/DeltaServiceTime)*100 where:
DeltaEnqueueAllocITLTime: difference of 'sum of time waited for sessions of foreground processes on the 'enqueue: TX mode 4, Transaction - allocate ITL entry' 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
To increase the number of ITL slots, recreate the table and increase the INITRANS parameter for the object with the contention. An alter table statement can be run to increase the ITL slots by increasing the value for INITRANS, but this will only take effect for new blocks.
Related Topics
About Alerts
About the Metric Detail Page
Editing Thresholds
Understanding Line Charts
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