IBM Books

Direct Reads From Database


Snapshot Information Level
Database
Table Space
 
Application

API Structure(s)
sqlm_dbase
sqlm_tablespace
sqlm_bp_info
sqlm_appl

Monitor Group
Buffer Pool
Buffer Pool
Buffer Pool
Buffer Pool

Resettable

Yes

 

Event Information Level
Database
Connection
Table Space

API Structure(s)
sqlm_db_event
sqlm_conn_event
sqlm_tablespace_event

 

API Element Name
Element Type

direct_reads
counter

 

Description:  The number of read operations that do not use the buffer pool.

Usage:  Use the following formula to calculate the average number of sectors that are read by a direct read:

 direct reads from database / direct read requests

When using system monitors to track I/O, this data element helps you distinguish database I/O from non-database I/O on the device.

Direct reads are performed in units, the smallest being a 512-byte sector. They are used when:

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