Using the Application Monitor › Wait Statistics (PF8)

Wait Statistics (PF8)

 PM-Rnn.n SYSTEM71         CA, Inc.                  V71      08.348 16:48:26.96
 CMD-->                                                             Window : 04

   04 Wait Statistics     DCMT     100926                  16:45:06.7131
        Wait Type     # Waits    Wait Time    Average Wait    Highest Wait
     TOT INT WAIT           5       .1984S        .0396S          .0474S
     DBIO READ              1       .0451S        .0451S          .0451S
     DBIO WRITE             1       .0339S        .0339S          .0339S
     SCR WRITE              1       .0339S        .0339S          .0339S
     PGM LOAD               2       .0854S        .0427S          .0474S

Screen Description

The Wait Statistics screen displays detailed statistics about waits that occurred during execution of the current task. If your task did not wait for a specific wait type, the wait type will not appear on your screen.

The total of the wait times shown on this screen may not match the total wait time shown on the General Statistics screen for the same task. This is because individual wait statistics are collected each time a task goes into and out of a wait type (also called an ECB type). The General Statistics wait time is calculated by subtracting the internal response time from the CPU time.

Using this Screen

• Press [PF2] to go to the DBkey Wait Statistics screen.
• Press [PF9] to go to the ADS Statistics screen.
• Press [PF4] to display wait statistics for the next task, as shown on the Task List screen.
• Press [PF5] to display wait statistics for the previous task, as shown on the Task List screen.

What To Look For

• Look for a number in the # Waits or Wait Time fields, which display the number and total duration of db-key waits, respectively. This can indicate db-key deadlocks among programs that are running concurrently. If this happens, consider implementing a site-standard database access sequence.
• Look for a consistent discrepancy between the wait time for internal waits (Tot Int Wait wait type) and the total wait time in the General Statistics screen. If you find a consistent discrepancy, investigate operating system overhead.
• Look at the types of waits that occur. Typical waits include DBIO reads and writes, journal writes, and terminal reads and writes. Waits that are more serious include waits for database keys, storage pools, and program pools.