Table manager
The table manager controls the locating, adding, deleting, locking, and unlocking of entries in certain CICS® tables. These operations can be performed while CICS is running.
Functions of the table manager
- Locate table entry
- For a given name, find the address of the table entry.
- Get next table entry
- For a given name, find the address of the next table entry in collating sequence. This can be used repeatedly to find all entries in a range (or all elements in the whole table).
- Add table entry
- For a given table entry, add it into the table.
- Quiesce a table entry
- For a given name, mark its directory segment as busy.
- Unquiesce a table entry
- For a given name, remove its directory segment from the ‘quiesce’ state.
- Delete a table entry
- For a given name, delete it and any associated alias. The entry must have been quiesced first.
- Create an index for a table
- Create a hash table of a given type.
- Add a name into a secondary index
- Given a primary name and a secondary name, add the names to the secondary index.
- Add an alias name
- For a given name, assign an alias name.
- Get next alias name
- For a given a name, find the next alias name (if any).
- Lock a table entry
- For a given a name, assign a read lock to it.
- Unlock a directory entry
- For a given a name, remove the associated read lock.
- Reset lock slots
- For a given name, reset the lock slots.
- Transfer lock to target task
- For a given a name and the address of a target TCA, transfer the read lock to the target task.
- Process deferred work element
- Make the changes made by the logical unit of work (LUW) visible at task syncpoint time.
Design overview
Locating, adding, deleting, locking, and unlocking entries in tables such as the terminal control table (TCT) are performed by the table manager program, DFHTMP.
Entries in these tables are also called “resources”. Because the structures of tables vary as entries are added or deleted, and a quick random access is required, a hash table mechanism is used to reference the table entries. In addition because fast access is needed for generic locates and ordered lists of entries, a getnext chain with a range table is used.
Control blocks
See Data areas for a detailed description of these control blocks.
Modules
DFHTMP
Exits
No global user exit points are provided for this function.
Trace
- AP 00EA, for which the trace level is AP 1.
Statistics
The statistics utility program, DFHSTUP, provides, for table management, statistics (for each table) on the amount of storage (expressed in bytes) used by the table manager to support each table (excluding storage used for the tables themselves).