VSAM-Buffer-Pool report (for batch regions only)

Using the VSAM-Buffer-Pool report

This report is written only for applications that you run in batch regions.

The primary use of the VSAM-Buffer-Pool report, an example is shown in the following example, is to see how many I/O operations were issued in each VSAM subpool.

                    *** VSAM BUFFER POOL STATISTICS ***
 FIX INDEX/BLOCK/DATA                                     N/Y/N
 SHARED RESOURCE POOL ID                                   VPL1
 SHARED RESOURCE POOL TYPE                                    D
 SUBPOOL BUFFER SIZE                                      4,096
 TOTAL BUFFERS IN SUBPOOL                                 1,000
 TOTAL HIPERSPACE BUFFERS IN SUBPOOL                         50
 
 
 RETRIEVE BY RBA CALLS                                      370
 RETRIEVE BY KEY CALLS                                   187583
 LOGICAL RECORDS INSERTED INTO ESDS                         310
 LOGICAL RECORDS INSERTED INTO KSDS                        9823
 LOGICAL RECORDS ALTERED IN THIS SUBPOOL                      0
 TIMES BACKGROUND WRITE FUNCTION INVOKED                      0
 SYNCHRONIZATION CALLS RECEIVED                           29923
 PERM WRT ERROR BUFFS NOW IN THE SUBPOOL                      0
 LARGEST NBR OF PERM ERR BUFFS EVEN IN THE SUBPL              0
 VSAM GET CALLS ISSUED                                        0
 VSAM SCHBFR CALLS ISSUED                                189290
 CONTROL INTERVAL REQUESTED ALREADY IN POOL                   0
*CONTROL INTERVAL READ FROM EXTERNAL STORAGE              51238
*VSAM WRITES INITIATED BY IMS                            138637
*VSAM WRITES TO MAKE SPACE IN THE POOL                     9288
 VSAM READS FROM HIPERSPACE BUFFERS                           0
 VSAM WRITES FROM HIPERSPACE BUFFERS                          0
 FAILED VSAM READS FROM HIPERSPACE BUFFERS                    0
 FAILED VSAM WRITES TO HIPERSPACE BUFFERS                     0
 
*TOTAL I/O OPERATIONS                                    199163

Fields in the VSAM-Buffer-Pool report

The VSAM-Buffer-Pool report is identical to the VSAM-Buffer-Pool report written by the DB monitor, with the following exceptions:

• Although the field names in the DB Monitor's VSAM Buffer Pool report are preceded by NUMBER OF, the fields in both reports have the same meaning.
• The //DFSSTAT VSAM-Buffer-Pool report does not keep track of the start trace and end trace times. This is unnecessary because information is always gathered for the //DFSSTAT reports from the beginning to the ending of the application's execution.
• The //DFSSTAT VSAM-Buffer-Pool report contains a TOTAL I/O OPERATIONS field, which is the sum of the following:
  • The number of times a CI was read into the buffer from the database (CONTROL INTERVAL READ FROM EXTERNAL STORAGE field in the report)
  • The number of times a buffer was written to the database (VSAM WRITES INITIATED BY IMS field in the report)
  • The number of times a buffer was written to the database so a new CI could be read into the buffer (VSAM WRITES TO MAKE SPACE IN THE POOL field in the report).
  • The //DFSSTAT VSAM-Buffer-Pool report includes a summary report. The summary report is preceded by SUBPOOL BUFFER SIZE=ALL. It contains a summary of read and write information for all VSAM Buffer Pool reports.

The fields that represent I/O operations are highlighted on the left by an asterisk (*).

Related reading: See VSAM-Buffer-Pool report for a description of the various fields in the report.