DB2 Version 9.7 for Linux, UNIX, and Windows

pages_from_block_ios - Total number of pages read by block I/O monitor element

The total number of pages read by block I/O into the block area of the buffer pool.

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
MON_GET_CONTAINER table function - Get table space container metrics	DATA OBJECT METRICS BASE
MON_GET_TABLESPACE table function - Get table space metrics	DATA OBJECT METRICS BASE

Table 2. Snapshot Monitoring Information
Snapshot Level	Logical Data Grouping	Monitor Switch
Buffer Pool	bufferpool	Buffer Pool

Usage

If block-based buffer pool is enabled, this element reports the total number of pages read by block I/O. Otherwise, this element returns 0.

To calculate the average number of pages sequentially prefetched per block-based I/O, divide the value of the pages_from_block_ios monitor element by the value of the block_ios monitor element. If this value is much less than the BLOCKSIZE option you have defined for the block-based buffer pool in the CREATE BUFFERPOOL or ALTER BUFFERPOOL statement, then block-based I/O is not being used to its full advantage. One possible cause for this is a mismatch between the extent size for the table space being sequentially prefetched and the block size of the block-based buffer pool.