This section describes the runtime parameters used for Adabas Transaction Manager.
ATM transaction manager operation is controlled through the following parameters:
Important:
These runtime parameters must be prefixed with ‘ATM’ when
defining them in the parameter input of the System Coordinator daemon within
which the Transaction Manager is operating. For example: ATM TMDRQ=10).
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Runtime |
Sets the number of entries allowed in the transaction manager’s internal request queue. |
10 - 32767 | 10 |
The ATM transaction manager uses an internal request queue for scheduling some of the tasks it needs to perform. The TMDRQ parameter determines the total number of entries in the queue that is used to service certain incoming, asynchronous requests. This queue is currently used only when the ATM RRMS interface is active.
When the RRMS interface is in use, the ATM dynamic request queue (DRQ) is used for communication between ATM RRMS exits and the ATM manager. The value specified for the TMDRQ parameter should therefore be increased if RRMS is to be used. Consider the number of global transactions that may reach a syncpoint at the same time, and increase TMDRQ by this number. You can specify a higher value, for safety, without incurring any performance degradation.
You can use Online Services to monitor usage of the DRQ. If you specify too small a value and the DRQ becomes full, backouts resulting in response code 9 (ADARSP009) are likely to occur.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Runtime |
Location of |
ATM | TARGETS | TARGETS |
The TMETDATA parameter determines
the database or databases that will store ET data.
The same TMETDATA parameter value must
be specified for all Adabas Transaction Manager (ATM) instances on the
network.
Possible values:
| Value | Explanation |
|---|---|
| ATM |
|
| TARGETS |
If the client storing
|
Notes:
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Runtime |
Sets time limit during which a global transaction can be open without being prepared. |
1 - 16777215 | 720 |
The TMGTT parameter approximately specifies the maximum elapsed time, in units of 1.048576 seconds, that a global transaction can remain open without being prepared. If the limit is exceeded, ATM automatically backs out the global transaction from all affected databases. The next time the client issues a transactional Adabas command, a response code 9 (ADARSP009) is returned.
It is recommended that TMGTT be smaller than the lowest TT parameter of any database running with DTP=RM.
The TMGTT parameter does not supersede the TT parameter settings of other databases. If a database times out a client who has an unprepared global transaction open, the global transaction is subsequently backed out. A response code 9 (ADARSP009) is returned if the client then issues a transactional command.
Note:
Transaction timeout can happen when a client session stops issuing
commands for a period of time. In these circumstances the transaction manager
has no opportunity to give a response code to the client, to indicate that the
timeout has taken place. In such cases, the pending response code will be
preserved and returned to the client at the first possible opportunity. For
further details, please refer to Pending Response Codes in
the Adabas Transaction Manager introduction.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Runtime | Sets severity threshold for the suppression of warning messages. | 0 | 4 | 8 | 0 |
Every message that the ATM manager sends to the console has a severity level. Message severity levels are explained in the Adabas Transaction Manager Messages and Codes.
Using the TMMSGSEV parameter, you can prevent messages with low severity levels from being written to the console by the ATM manager. This parameter has no effect on messages that are issued by the ATM client proxy, or during the early part of the transaction manager’s initialization.
Possible values:
| Value | Description |
|---|---|
| 0 | No messages are suppressed. |
| 4 | Messages of severity less than 4 are not sent to the console. |
| 8 | Messages of severity less than 8 are not sent to the console. |
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Runtime | Controls restart handling of problematic transactions. | NORMAL | FORCE | FORCEALL | NORMAL |
When an ATM manager restarts, it rebuilds its global transaction list as nearly as possible to its latest state when it was last executing. It then attempts to complete or back out any incomplete global transactions. The TMRESTART parameter determines the manager’s restart action with regard to global transactions and transaction branches that remain incomplete at the end of this process.
Possible values:
| Value | Description |
|---|---|
| NORMAL | Any incomplete transactions remain in an incomplete state until such time as they can be completed. |
| FORCE | ATM transfers to the suspect transaction journal (STJ) the details of every incomplete global transaction that has its root local to this ATM manager. The details of these transactions are deleted from ATM’s recovery information, the originating clients are closed, and any related internal resources are freed. ATM can no longer guarantee integrity for such global transactions. |
| FORCEALL | Details of all unresolved global transactions and transaction branches are transferred to the STJ. The details are deleted from ATM’s recovery information, the originating clients are closed, and any related internal resources are freed. ATM can no longer guarantee integrity for the affected global transactions. |
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Runtime | Indicates whether or not the ATM manager is to interact with an external transaction coordinator. | NONE | RRMS | NONE |
The TMSYNCMGR parameter determines whether or not the ATM manager registers and interacts with an external transaction coordinator.
Possible values:
| Value | Description |
|---|---|
| NONE | The ATM manager will not interact proactively with an external transaction coordinator. This setting does not preclude the use of the CICS Syncpoint Manager, which interfaces directly with the ATM’s client proxy component and not with the ATM manager. |
| RRMS | The ATM manager will register with the IBM Recoverable Resource Management Services so that it can participate in transactions that involve other RRMS-enabled resource managers. This parameter value is valid only for z/OS systems in which RRS (a component of RRMS) is active. The current version of ATM offers participation in RRMS-coordinated two-phase commit for single-user, single-TCB batch applications and for applications running under Com-plete or IMS TM. |
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Runtime | Defines the first one or two characters of dynamically allocated Client IDs. | up to 2 alphanumeric characters | TM |
To aid interpretation of Adabas Online Services displays and diagnostic logs, the ATM manager dynamically allocates an 8-byte client identifier (TCID) for each client session that engages in transactional activity. These client identifiers are simply labels, and have no operational significance.
The format of a dynamically allocated TCID is
ppnnxxxx
—where
pp is the value of the TMTCIDPREF parameter, left-justified and with trailing blanks if required.
nn is the 2-byte binary Node ID of the Adabas System Coordinator daemon within which the ATM transaction manager is running as a service.
xxxx is a 4-byte binary suffix. Suffixes are allocated in sequence and are reused. The first TCID to be allocated has a suffix of zeros.
