Database I/O data

MainView for IMS collects all database activity indicators per transaction at the database level.

A separate segment is appended to the MainView for IMS transaction record per accessed database to hold the counts (see Log-record-layouts). This process allows later reporting by transaction, by user (for accounting), and by database, which is always true for the DL/I calls. Each call is counted by type (GU, ISRT, and so on) and per DBD.

These database segments also contain fields for several I/O-related counts. I/O activity is split into categories according to whether the I/O was a read or write, key or nonkey access. One additional count, called NO I/O, is unique to MainView for IMS. This count is a measure of IMS overhead and is the number of requests to the IMS buffer handler that do not result in I/O. These counts can be affected by the Event Collector parameters.

Note

If DBTNAME=DD is specified, database reads and writes and reads without I/O counts (NO I/O counts) are collected at the data set level, except for Fast Path DEDBs.

The following topics discuss the use of the DBIO Event Collector parameter:

For more information about the Event Collector parameters, seeMainView for IMS and MainView for DBCTL Customization.

Related topic

IMS resource utilization files (IRUFs)

 

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