Pointer check for online full-function databases

To completely check the pointers of online full-function databases, static images of the databases must be captured, which requires the online databases to be stopped. This restriction cannot be avoided.

However, you can reduce the amount of time that the databases are stopped by using two features of IMS HP Image Copy: the HASH Check option with the TOIAUTO (or TOIAUTO_Q) keyword and the Advanced Image Copy Services (FASTIC). By enabling these two features, you can run HASH pointer check for online databases in pseudo online pointer check mode. In this mode, HASH pointer check is run with automatic database start and stop operations, which result in the databases being unavailable for the shortest amount of time possible. This function is called the Online Pointer Checking function.

When you run an IMS HP Image Copy job in pseudo online pointer check mode, the IMS HP Image Copy job works as follows:
  1. IMS HP Image Copy automatically stops the database.
  2. IMS HP Image Copy creates FlashCopy® files of databases.
  3. IMS HP Image Copy automatically restarts the databases.
  4. IMS HP Image Copy runs a HASH pointer check on the FlashCopy files.
  5. IMS HP Image Copy deletes the FlashCopy files or keeps the FlashCopy files as Fast Recovery image copies.
  6. IMS HP Image Copy ends the job.

By running jobs in this mode, you can consistently run HASH pointer check for online full-function databases.

When a job is run in this mode, the online databases become temporarily unavailable (they are taken offline or quiesced) during processes 1 and 2, but you do not need to manually issue any IMS commands to stop or restart the databases. IMS HP Image Copy automatically issues the required IMS commands to stop or restart the databases. To help ensure that these commands run successfully, consider running the job during a time period in which the databases are rarely updated.

In the pseudo online pointer check mode process, IMS HP Image Copy creates FlashCopy files. You can keep the FlashCopy files as Fast Recovery image copies or have the files deleted as shadow data sets. When the FlashCopy files are kept as Fast Recovery image copies, IMS HP Image Copy registers the IC records to DBRC RECON data sets. When the FlashCopy files are processed as shadow data sets, IMS HP Image Copy does not register the IC records to DBRC RECON data sets. You can also create image copy data sets in the standard image copy format of IMS HP Image Copy in addition to the FlashCopy files. See Examples for running Online Pointer Checking for full-function databases for JCL examples.

Notes:
  • The Online Pointer Checking function works for IMS full-function databases. You cannot use this function for DEDBs.
  • The Online Pointer Checking function can be used when you run IMS HP Image Copy with the FABJMAIN program. You cannot use this function when you run IMS HP Image Copy with IMS compatible JCL.

Enabling pointer check for online full-function databases

To run an IMS HP Image Copy job in pseudo online pointer check mode for full-function databases, you must specify the following keywords on the ICEIN IC, AIC, CIC, or ACIC statement:
HDPC=Y
This required keyword requests a HASH pointer check for full-function databases.
TOIAUTO=Y or TOIAUTO_Q=Y
This required keyword requests IMS Tools Online System Interface to issue IMS commands. Through the interface, IMS HP Image Copy issues the /DBDUMP or the /DBRECOVERY command, or it requests to quiesce the databases.
FASTIC=(opt,COPY) or FASTIC=(opt,FDUMP)
This required keyword requests the FlashCopy process of the Advance Copy Services. If you specify FASTIC=(opt,FDUMP), you must also specify the SHDWDSN or the SHDWHLQ keyword.
ICOUT=%NO or STACK=%NO
This optional keyword requests that image copy data sets are not created.