This parameter determines
the amount of the memory, in pages, to allocate for database system
monitor data. Memory is allocated from the monitor heap when database
monitoring activities are performed.
Monitoring activities
include turning on monitor switches, resetting monitor data, activating
an event monitor or sending monitor events to an active event monitor.
With Version 9.5, this database configuration parameter has
a default value of AUTOMATIC, meaning that the monitor
heap can increase as needed until the instance_memory limit
is reached.
- Configuration type
- Database manager
- Applies to
-
- Database server with local and remote clients
- Database server with local clients
- Partitioned database server with local and remote clients
- Parameter type
- Configurable online
- Default [range]
- Automatic [0 - 60 000]
- Unit of measure
- Pages (4 KB)
- When allocated
- When the database manager is started with the db2start command
- When freed
- When the database manager is stopped with the db2stop command
A value of zero prevents the database manager from
collecting database system monitor data.
Recommendation: The
amount of memory required for monitoring activity depends on the number
of monitoring applications (applications taking snapshots or event
monitors), which switches are set, and the level of database activity.
If
the configured memory in this heap runs out and no more unreserved
memory is available in the instance shared memory region, one of the
following events will occur:
- When the first application connects to the database for which
this event monitor is defined, an error message is written to the
administration notification log.
- If an event monitor being started dynamically using the SET EVENT
MONITOR statement fails, an error code is returned to your application.
- If a monitor command or API subroutine fails, an error code is
returned to your application.
- If
an application needs to send an event monitor record but cannot allocate
the record out of monitor heap, the application might be blocked until
a record is allocated.