Control blocks

DFHD2SS (CICS-DB2 static storage)

CICS®-DB2® static storage (D2SS) is acquired by DFHSIB1 and anchored off field SSZDB2 in the static storage address list DFHSSADS. The static storage is initialized by the CICS-DB2 restart program DFHD2RP. Its lifetime is that of the CICS region. CICS-DB2 static storage holds information such as storage manager, lock manager and directory manager tokens acquired during restart processing before any other CICS-DB2 control blocks are installed.

DFHD2GLB (CICS-DB2 global block)

The DFHD2GLB block represents an installed DB2CONN definition. It is getmained by DFHD2TM when a DB2CONN is installed and freemained by DFHD2TM when a DB2CONN is discarded. It holds CICS-DB2 state data global to the connection and also the state data for pool threads and commands threads. The pool and command sections of the DFHD2GLB are mapped by a common type definition DFHD2RCT which is also used to map the DFHD2ENT control block.

The DFHD2GLB block is anchored off CICS-DB2 static storage in field D2S_DFHD2GLB.

DFHD2ENT (CICS-DB2 DB2ENTRY block)

The DFHD2ENT block represents an installed DB2ENTRY definition. It is getmained by DFHD2TM when a DB2ENTRY is installed and freemained by DFHD2TM when a DB2ENTRY is discarded. It uses a type definition DFHD2RCT in common with the pool and command sections of the DFHD2GLB block to achieve a common layout for all three areas. A DFHD2ENT block is located using a directory manager index that is keyed off the RDO name of the DB2ENTRY.

DFHD2TRN (CICS-DB2 DB2TRAN block)

The DFHD2TRN block represents an installed DB2TRAN definition. It is getmained by DFHD2TM when a DB2TRAN is installed and freemained by DFHD2TM when a DB2TRAN is discarded. A DB2TRAN can be located in two ways. Firstly by a directory manager index keyed off the RDO name of the DB2TRAN. Secondly by a directory manager index keyed off the transaction id associated with the DB2TRAN.

DFHD2CSB (CICS-DB2 connection block)

The DFHD2CSB block represents a CICS-DB2 connection, with or without a thread. A DFHD2CSB is created by DFHD2EX1 prior being passed to DFHD2EX3 or DFHD2D2. A DFHD2CSB is freed by DFHD2EX1 after the DFHD2EX3 program has returned to MVS™, or when DFHD2D2 indicates it should be freed. A DFHD2EX3 block is anchored off one of several CSB chains from a DB2ENTRY or the DFHD2GLB depending on the state of the connection and the DB2 thread.

DFHD2GWA (CICS-DB2 global work area)

The DFHD2GWA block is the global work area of the CICS-DB2 task related user exit (TRUE) DFHD2EX1. It is getmained when the TRUE is enabled, and freemained when the TRUE is disabled. The D2GWA holds a chain of LOT control blocks representing the tasks currently using the CICS-DB2 interface.

DFHD2LOT (CICS-DB2 life of task block)

The DFHD2LOT block is the task local work area of the CICS-DB2 task related user exit (TRUE) DFHD2EX1. It is getmained by DFHERM when a task first calls the CICS-DB2 TRUE. It is freemained by DFHERM at end of task. Its address is passed to DFHD2EX1 by DFHERM in parameter UEPTAA in the DFHUEPAR RMI parameter list.

The DFHD2LOT holds CICS-DB2 state information for a CICS task using the CICS-DB2 interface.

[[ Contents Previous Page | Next Page Index ]]