HCHECK overview

The HCHECK function checks information in the RECON data sets that is associated with the IMS database subsystem to identify potential problems with the recoverability of one or more databases. HCHECK uses information from the RECON data sets, the IMS Recovery Expert repository, and the MVS catalog.

The HCHECK function requires that you specify the target databases using the DBLIST supporting function.

The HCHECK function can use the RECON copy data sets that are created by the RECONCOPY supporting function, or the data sets identified on the ALTRECONS supporting function.

Note: Use either RECONCOPY or ALTRECONS in conjunction with HCHECK to prevent input/output (I/O) to the live RECON data sets.

Processing System Level Backup Image Copies

The RECON can contain Image Copy records that represent System Level Backups (SLB). The following considerations pertain to using HCHECK to process SLBs.

The data set name for the SLB Image Copy is symbolic only and is formatted as follows:
```
SLB.Ixxxx.Dxxxx.dbdname.ddname
```
These data sets are never cataloged, nor does any function try to allocate or open them.
When USESLBIC(N) is specified, RECON Image Copy records that represent SLBs are treated by HCHECK no differently than any other Image Copy records with one exception: HCHECK(VERIFY) does not verify as to whether they are cataloged.
You can use the VERIFY function with the LIST option to determine if there are SLB Image Copy records in the RECON.

IMS Database Recovery Facility VERIFY, IMS Database Recovery Facility Extended Functions VERIFY, and IMS Database Recovery Facility Extended Functions HCHECK functions all recognize these data set names as symbolic only.
When USESLBIC(Y) is specified, and whenever necessary, IMS Database Recovery Facility Recovery, IMS Database Recovery Facility VERIFY, and IMS Database Recovery Facility Extended Functions VERIFY functions issue a NOTIFY.IC command to DBRC for the most recent SLB that exists relative to the function’s specified time parameter (for example, RCVTIME or "current").
HCHECK(VERIFY) does not issue a NOTIFY.IC because SLB.Ixxxx.Dxxxx.dbdame.ddname data sets are never cataloged and so do not apply to its function. Instead, HCHECK(VERIFY) lists on the report that there is a symbolic SLB Image Copy record in the RECON and that it is not cataloged.
It is a best practice to delete any Image Copy records that represent deleted SLBs.
Otherwise, the HCKECK functions of ICNONE, ICFREQ, MINBAT, and MINONL would consider these IC records as representing a usable backup. This correlates with the fact that IMS Database Recovery Facility Recovery and IMS Database Recovery Facility VERIFY would also consider these records as valid and attempt to use the deleted SLBs.
Another possible situation occurs when an SLB exists, yet there is no RECON IC record that represents it.
The VERIFY function with any of its options (LIST, ALLOC, OPEN) causes representative IC records to be written to the RECON.

HCKECK functions ICNONE, ICFREQ, MINBAT, and MINONL consider the corresponding SLBs as potentially valid backups. However, they do not write NOTIFY.IC records to the RECON because it is not necessary relative to their function.