Monitoring storage of the group buffer pool

By periodically monitoring the storage use of the group buffer pool, you can avoid data outages that are caused by a lack of storage in the group buffer pool.

Procedure

Begin general-use programming interface information.

To monitor storage of the group buffer pool:

Issue the DISPLAY GROUPBUFFERPOOL command with the GDETAIL option.

The GDETAIL statistics show a snapshot value of the number of changed pages in the group buffer pool. Ensure that this snapshot value ( C ) does not rise significantly above the group buffer pool castout threshold ( B × A ). The following figure highlights the key fields from the report.

Figure 1. Partial output of DISPLAY GROUPBUFFERPOOL command. Ensure that the SNAPSHOT value does not rise significantly above the group buffer pool castout threshold.

DSNB756I -DB1A   CLASS CASTOUT THRESHOLD                    = 5,0
               A GROUP BUFFER POOL CASTOUT THRESHOLD        = 30%
                 GROUP BUFFER POOL CHECKPOINT INTERVAL      = 4 MINUTES
                 RECOVERY STATUS                            = NORMAL
                 AUTOMATIC RECOVERY                         = Y
DSNB759I -DB1A   NUMBER OF DIRECTORY ENTRIES                = 61394
               B NUMBER OF DATA PAGES                       = 11370
                 NUMBER OF CONNECTIONS                      = 3
DSNB783I -DB1A CUMULATIVE GROUP DETAIL STATISTICS SINCE 15:35:23 Mar 17, 2002
DSNB784I -DB1A GROUP DETAIL STATISTICS
⋮
DSNB786I -DB1A   WRITES
                   CHANGED PAGES                      = 1576
                   CLEAN PAGES                        = 0
                   FAILED DUE TO LACK OF STORAGE      = 0
                 C CHANGED PAGES SNAPSHOT VALUE       = 311
⋮

End general-use programming interface information.