DB2 Version 9.7 for Linux, UNIX, and Windows

lock_waits - Lock waits monitor element

The total number of times that applications or connections waited for locks.

Table 1. Table Function Monitoring Information
Table Function	Monitor Element Collection Level
MON_GET_CONNECTION table function - Get connection metrics	REQUEST METRICS BASE
MON_GET_CONNECTION_DETAILS table function - Get detailed connection metrics (reported in DETAILS XML document)	REQUEST METRICS BASE
MON_GET_SERVICE_SUBCLASS table function - Get service subclass metrics	REQUEST METRICS BASE
MON_GET_SERVICE_SUBCLASS_DETAILS table function - Get detailed service subclass metrics (reported in DETAILS XML document)	REQUEST METRICS BASE
MON_GET_UNIT_OF_WORK table function - Get unit of work metrics	REQUEST METRICS BASE
MON_GET_UNIT_OF_WORK_DETAILS table function - Get detailed unit of work metrics (reported in DETAILS XML document)	REQUEST METRICS BASE
MON_GET_WORKLOAD table function - Get workload metrics	REQUEST METRICS BASE
MON_GET_WORKLOAD_DETAILS table function - Get detailed workload metrics (reported in DETAILS XML document)	REQUEST METRICS BASE
MON_GET_ACTIVITY_DETAILS table function - Get complete activity details (reported in DETAILS XML document)	ACTIVITY METRICS BASE
MON_GET_PKG_CACHE_STMT table function - Get SQL statement activity metrics in the package cache	ACTIVITY METRICS BASE
MON_GET_PKG_CACHE_STMT_DETAILS table function - get detailed metrics for package cache entries	ACTIVITY METRICS BASE

Table 2. Snapshot Monitoring Information
Snapshot Level	Logical Data Grouping	Monitor Switch
Database	dbase	Basic
Application	appl	Basic

For snapshot monitoring, this counter can be reset.

Table 3. Event Monitoring Information
Event Type	Logical Data Grouping	Monitor Switch
Activities	event_activity (reported in the details_xml document)	ACTIVITY METRICS BASE
Activities	event_activitymetrics	ACTIVITY METRICS BASE
Statistics	event_scstats (reported in the metrics document)	REQUEST METRICS BASE
Statistics	event_wlstats (reported in the metrics document)	REQUEST METRICS BASE
Unit of work	Reported in the system_metrics document.	REQUEST METRICS BASE
Database	event_db	-
Connection	event_conn	-
Package cache	Reported in the activity_metrics document.	ACTIVITY METRICS BASE
Statistics	event_scmetrics*	REQUEST METRICS BASE
Statistics	event_wlmetrics*	REQUEST METRICS BASE
* When returned as part of this logical data group, this element reflects the change in value of this metric since the last statistics collection or database activation, whichever was more recent.

Usage

At the database level, this is the total number of times that applications have had to wait for locks within this database.

At the application-connection level, this is the total number of times that this connection requested a lock but had to wait because another connection was already holding a lock on the data.

This element may be used with lock_wait_time to calculate, at the database level, the average wait time for a lock. This calculation can be done at either the database or the application-connection level.

If the average lock wait time is high, you should look for applications that hold many locks, or have lock escalations, with a focus on tuning your applications to improve concurrency, if appropriate. If escalations are the reason for a high average lock wait time, then the values of one or both of the locklist and maxlocks configuration parameters may be too low.