The ICMRMCONTROL table describes the table definitions
related to prefetching.
Table 1. ICMRMCONTROL
| Attribute |
Type |
Value |
| PREFETCHENABLED |
SMALLINT |
NOT NULL, |
Table 2. ICMRMPREFETCH
| Attribute |
Type |
Value |
| ITEMID |
CHAR(26) |
NOT NULL |
| VERSIONID |
SMALLINT |
|
| EXTOBJNAME |
CHAR(44) |
NOT NULL |
| SOURCECOLLNAME |
CHAR(44) |
NOT NULL |
| PREFETCHCOLLNAME |
CHAR(44) |
NOT NULL |
| REQUESTTIMESTAMP |
TIMESTAMP |
NOT NULL |
| STATETIMESTAMP |
TIMESTAMP |
NOT NULL |
| OAMRETURNCODE |
SMALLINT |
|
| OAMREASONCODE |
CHAR(8) |
|
| VOLSER |
CHAR(6) |
|
| OPERATION |
VARCHAR(128) |
NOT NULL |
| PREFETCHSTATE |
VARCHAR(128) |
NOT NULL |
| PRIMARY KEY (EXTOBJNAME) |
|
|
- ITEMID
- Generated by the library server during the object store transaction.
- Example:
ITEMID: A1001001A03L09B64813I92553
- VERSIONID
- When versioning is enabled, this value denotes a given instance of an object.
- Example:
VERSIONID: 1
- EXTOBJNAME
- The EXTOBJNAME is the ITEMID and VERSIONID combined and "." delimited, and represents a unique
object locator within Object Access Method (OAM).
- Example:
EXTOBJNAME: A1001001.A03L09.B64813.I92553.V001
- SOURCECOLLNAME
- The name of the collection that the object was originally stored under and, the source of the
prefetch operation.
- Example:
SOURCECOLLNAME: CLLCT001
- PREFETCHCOLLNAME
- Generally represents a collection backed by a fast access medium such as DASD and is the target
of a prefetch operation.
- Example:
PREFETCHCOLLNAME: CLLCT002
- REQUESTTIMESTAMP
- The time when a request was made to prefetch an object.
- Example:
REQUESTTIMESTAMP: 2023-12-09 21:48:22.778167000
- STATETIMESTAMP
- Reflects the time that PREFETCHSTATE was modified. For example, when an object is initially
requested to be prefetched, the REQUESTTIMESTAMP and the STATETIMESTAMP are the same and
PREFETCHSTATE is set to INITIATED. Once the processing of the prefetch request begins,
PREFETCHSTATE is updated to WORKING. STATETIMESTAMP is also updated to reflect the time the
prefetch processing began. If the prefetch processing completes successfully, PREFETCHSTATE
is updated to COMPLETE. If there is a failure, PREFETCHSTATE is updated to FAILED. In either
case, STATETIMESTAMP is also updated with the current timestamp.
- Example:
STATETIMESTAMP: 2023-12-09 21:48:22.778167000
- OAMRETURNCODE
- An integer value that represents the return code from an OAM operation. Prefetching an object
requires multiple calls to the OAM interface. Therefore, the return code from OAM indicates
the success or failure of a given prefetch operation. Since the prefetch function currently
runs asynchronously, the calling application has no way of knowing the status of a given
prefetch operation, therefore it is important to store this status information persistently
for later status query.
- Example:
OAMRETURNCODE: 8
- OAMREASONCODE
- Provides detailed information about the OAMRETURNCODE failure
and is the character representation of the hexadecimal value used
to locate the reason code description in the DFSMSdfp Diagnosis
Reference Guide (GY27-7618-03). Example
OAMREASONCODE:
2C040100
- VOLSER (for future use)
- Represents the tape volume on which a given object can be stored. This value is included for
grouping prefetch requests according to the tape volume
where they are to prevent "thrashing" of the tape
drives.
- OPERATION
- This value indicates the operation that is to be performed. The only valid value for this column
is PREFETCH.
- Example:
OPERATION: PREFETCH
- The OPERATION column is included for future extensibility and therefore will contain other
values in the future.
- PREFETCHSTATE
- Indicates the progress of a prefetch transaction. The following
list provides the valid values for this column:
- INITIATED
- The initial state when a prefetch request is inserted into the
ICMRMPREFETCH table.
- WORKING
- The updated state indicating that the prefetch process has started
processing the prefetch request of the object.
- COMPLETE
- The updated state indicating that the prefetch process has ended
successfully.
- FAILED
- The updated state indicating that the prefetch process returned
with a non-zero error condition.