Considerations for collecting sensor data from full-function databases

Certain considerations apply when collecting sensor data from full-function databases.

Collecting sensor data from a database that is being updated

DB Sensor can collect sensor data from an online database or from a database that is being updated by batch jobs.

However, when the database data set is VSAM, due to file system limitations, the following data element values reflect the database status of when the file was opened. Consequently, the values do not reflect the latest database status.

  • DB_RBA_HIGH_USED
  • DB_RBA_HIGH_ALLOC
  • DB_UNUSED_BYTES
  • DB_PCT_UNUSED_BYTES
  • DB_PCT_OF_MAX_DS_SIZE
  • DB_PCT_BYTES_SEG (Note)
  • DB_PCT_BYTES_FREE_SPACE (Note)
  • DB_NUM_DBDS_BLOCKS (Note)
  • DB_NUM_CI_SPLIT
  • DB_PCT_NUM_CI_SPLIT
  • DB_NUM_CA_SPLIT
  • DB_PCT_NUM_CA_SPLIT
  • DBX_NUM_IPS
  • DBX_NUM_IPS_OVFL
  • DBX_PCT_IPS_OVFL
  • DBX_RBA_HIGH_USED
  • DBX_RBA_HIGH_ALLOC
  • DBX_UNUSED_BYTES
  • DBX_PCT_UNUSED_BYTES
  • DBX_PCT_OF_MAX_DS_SIZE
  • DBX_NUM_DBDS_BLOCKS
  • DBX_NUM_CI_SPLIT
  • DBX_PCT_NUM_CI_SPLIT
  • DBX_NUM_CA_SPLIT
  • DBX_PCT_NUM_CA_SPLIT
Note: For DB_PCT_BYTES_SEG, DB_PCT_BYTES_FREE_SPACE, and DB_NUM_DBDS_BLOCKS, if the database data set is a VSAM KSDS (that is, HISAM or SHISAM), data element values do not reflect the latest status. For VSAM ESDS data sets and VSAM linear data sets (OSAM LDS), which include HDAM, HIDAM, PHDAM, and PHIDAM, these data element values always reflect the latest status.

To obtain the latest values, consider running DB Sensor as follows:

  • For a database that is being updated by batch jobs, run DB Sensor after the batch jobs are complete.
  • For an online database, stop the database updates by issuing the /STOP or the /DBR command, or specify the IMS Tools Online System Interface XCF group name for the DB Sensor process. If you specify the XCF group name, DB Sensor uses IMS Tools Online System Interface to collect the latest VSAM statistics and then sets the data element values based on the collected statistics.
Restriction: For VSAM data sets that use SHAREOPTION(1,3), the file system does not permit DB Sensor to collect sensor data while the database is being updated.