DB2 Version 9.7 for Linux, UNIX, and Windows

pool_no_victim_buffer - Buffer pool no victim buffers monitor element

Number of times an agent did not have a preselected victim buffer available.

Table 1. Table Function Monitoring Information
Table Function	Monitor Element Collection Command and Level
MON_GET_BUFFERPOOL table function - Get buffer pool metrics	DATA OBJECT METRICS BASE

Table 2. Snapshot Monitoring Information
Snapshot Level	Logical Data Grouping	Monitor Switch
Database	dbase	Buffer Pool
Tablespace	tablespace	Buffer Pool
Buffer Pool	bufferpool	Buffer Pool

For snapshot monitoring, this counter can be reset.

Table 3. Event Monitoring Information
Event Type	Logical Data Grouping	Monitor Switch
Database	event_db	-
Tablespace	event_tablespace	-

Usage

This element can be used to help evaluate whether you have enough page cleaners for a given buffer pool when using proactive page cleaning.

When the DB2_USE_ALTERNATE_PAGE_CLEANING registry variable is ON, the pool_no_victim_buffer element counts the number of times that an agent did not find a preselected victim buffer available for immediate use, and was forced to search the buffer pool for a suitable victim buffer.

If the value of pool_no_victim_buffer element is high relative to the number of logical reads in the buffer pool, then the DB2® database system is having difficulty ensuring that sufficient numbers of good victims are available for use. Increasing the number of page cleaners will increase the ability of DB2 to provide preselected victim buffers.

When the DB2_USE_ALTERNATE_PAGE_CLEANING registry variable is OFF, the pool_no_victim_buffer element has no predictive value, and can be safely ignored. In this configuration, the DB2 database system does not attempt to ensure that agents have preselected victim buffers available to them, so most accesses to the buffer pool will require that the agent search the buffer pool to find a victim buffer.