Correct operation of the ATM transaction manager and the Adabas Transaction Manager client proxy depends on the settings of client runtime controls. These are defined and maintained using Online Services. Their settings determine the logic to be used by the proxy during transaction processing. These settings should be determined according to production system requirements, and should be tested before being used in production.
Note:
The NumberOfLogRecordEntries
control setting requires particular attention. This setting determines the
amount of memory, per client session, that is allocated for logging diagnostic
information. In a TP system that services many users, a setting of 100, for
example, could quickly consume a large amount of memory. In such systems,
choose a small value for this setting. See the section
Client
Sessions for more information.
This section describes each ATM runtime control:
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime |
Indicates whether or not ATM is to provide transaction coordination for this client session. |
ON | OFF | OFF |
Possible values:
| Value | Description |
|---|---|
| ON | Users will perform distributed transaction processing, and ATM is to provide transaction coordination. |
| OFF | ATM is not to be used for coordinating transactions for users in this client session. |
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime |
Identifies the Adabas System Coordinator group in which the client session or TP system will execute. |
Any valid Adabas System Coordinator group name | A valid group name must be provided |
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Sets the maximum number of databases with which a client session can have an active session at one time. | number | 4 |
The setting should include all databases without regard to their
DTP parameter settings.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Indicates whether or not internal logging is to be performed, and if so, how much space, per client session, will be used for this purpose. | 0-4096 | 0 |
The ATM client proxy is capable of logging internal events for diagnostic purposes. The log buffer area is reused cyclically.
Possible values:
| Value | Description |
|---|---|
| 0 | The client proxy will not acquire log buffer areas and will not log internal events. |
| 1-4096 | The number of entries to be reserved for internal event logging. Each entry requires 96 bytes. |
Note:
Do not specify a high value for a TP system that services a large
number of users since this may result in memory becoming exhausted.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Determines the action to be taken whenever an unsolicited syncpoint request is received. | GLOBAL | LOCAL | LOCAL |
An unsolicited syncpoint request is a syncpoint request which has not been "seen" by the client’s local client proxy. Such unsolicited syncpoint requests can occur if:
The client runtime control
Client-sideTransactionManager is in effect; or
the Transaction Manager executes with the parameter setting
TMSYNCMGR=RRMS; or
an application could cause a participating trigger to execute,
causing an ET or BT
commands.
Possible values are:
| Value | Description |
|---|---|
| LOCAL: |
Transaction control is exclusive to the local client proxy. Unsolicited syncpoints will still be processed, however the client’s next Adabas command will be rejected with a response code 243. |
| GLOBAL |
Transaction control is not exclusive to the local client proxy. Unsolicited syncpoints will be processed normally. |
For more information on syncpoints, refer to the section Syncpoint Processing Options.
When running with the Client-side Transaction
Manager option set to YES in a CICS/RMI environment, a decision to
commit or back out a global transaction can occur in several ways:
the application program issues ET or
BT;
the application program issues EXEC CICS
SYNCPOINT (or SYNCPOINT ROLLBACK);
the CICS task terminates, normally or abnormally, when updates are pending.
In the first case, the ATM client proxy is aware of the syncpoint decision.
In all other cases, from the client proxy’s point of view, the syncpoint is unsolicited. If the client session is at global transaction status, an unsolicited syncpoint has no effect on Adabas databases, other than to cause held ISNs to be released. On the other hand, if an unsolicited syncpoint occurs when Adabas changes are pending, ATM is instructed to commit the changes; in this case also, held ISNs are released.
If such unsolicited syncpoints are acceptable in your CICS system,
specify GLOBAL for the TransactionControl client control
- otherwise, specify LOCAL to treat unsolicited syncpoint requests as
errors.
Most CICS applications run in pseudo-conversational mode; that is, the
current CICS task terminates when a screen I/Os occurs. If ATM CICS/RMI is
installed and active, and client runtime control
TransactionModel is set to MESSAGE, an application that
runs in pseudo-conversational mode cannot keep an Adabas transaction open
across screen I/Os because an implied (unsolicited) commit syncpoint occurs at
every screen I/O. In this mode, it is not possible for a transaction to remain
open across screen I/Os. See the TransactionModel control
for details of a different way of responding to unsolicited syncpoints.
If the client control TransactionControl is set
to LOCAL and the syncpoint resulted in Adabas changes being committed, the next
Adabas call following a screen I/O returns response code 243.
Various Natural features including some SYSSEC functions maintain open
Adabas transactions across screen I/Os. In a CICS/RMI environment operating
with the client runtime control TransactionModel set to
MESSAGE, such functions are likely to
fail with a NAT3243 error when
TransactionControl is set to LOCAL; or
be unable to back out in case of errors when
TransactionControl is set to GLOBAL; or
fail with response code 144.
You should therefore execute Natural system functions in one of the following ways:
execute Natural system functions in a system other than CICS, or in a CICS system using a link module in which the RMI is not active; or
execute Natural system functions in a client session that operates
with the client runtime control TransactionModel set to
DYNAMIC; or
execute Natural system functions in conversational mode when using the CICS Resource Manager Interface.
When ATM’s RRMS interface is active, a decision to commit or back out a global transaction can occur in several ways:
the application program issues ET or
BT;
the application program issues SRRCMIT or
SRRBACK;
the application or some other agent issues
ATRCMIT or ATRBACK.
In the first case, the ATM’s client proxy is aware of the syncpoint decision. In other cases, from ATM’s point of view, the syncpoint is unsolicited. If the client session is at global transaction status, an unsolicited syncpoint has no effect on Adabas databases, other than to cause held ISNs to be released. On the other hand, if an unsolicited syncpoint occurs when Adabas changes are pending, ATM is instructed to commit the changes; in this case, also, held ISNs will be released.
If unsolicited syncpoints are acceptable in your system, set the client
control TransactionControl to GLOBAL - otherwise, set
TransactionControl to LOCAL to treat unsolicited
syncpoint requests as errors. If TransactionControl is
set to LOCAL and an unsolicited syncpoint causes a client sessions's Adabas
changes to be committed, the next Adabas call issued by the user returns
response code 243.
If ATM runs with the
HostSystemTransactionManager option is specified for IMS
TM systems whose transactions are coordinated by RRMS,
TransactionControl must be set to GLOBAL for these IMS
systems.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Indicates whether or not the ATM client proxy is
to switch a client session from DTP to serial ET/BT
mode if the local ATM transaction manager becomes unavailable.
|
YES | NO | FORCE | FORCE |
Possible values:
| Value | Description |
|---|---|
| YES | The ATM client proxy is to switch a client
session from DTP to serial ET/BT mode if the local
transaction manager becomes unavailable. A response code will be returned to
indicate that the local TM is unavailable.
|
| NO | The ATM client proxy is not to switch a client
session from DTP to serial ET/BT mode if the local
TM becomes unavailable.
|
| FORCE | A client session is to be switched to serial mode if necessary. No notification is provided. |
For more information regarding DTP and Serial mode processing, refer to the section Processing Modes.
Note:
If ATM automatically switches a client session to serial
ET/BT mode when the session has a transaction open,
the client might receive unexpected response codes, even if the runtime control
value for serial processing is set to FORCE. For example, the transaction might
be backed out, and response 9 returned to the client. Other response codes,
such as response 240 subcode 88, might be given, depending on how far the
transaction had progressed, and there is a possibility that the transaction
will remain unresolved until the ATM transaction manager is once again able to
carry out its responsibilities. Even so, the setting of value FORCE will ensure
minimum disruption when a switch to serial ET/BT
mode is necessary, and will probably allow most clients to continue processing
without noticing the switch.
From the viewpoint of a client session, an external
database is a database that executes outside the scope of the session’s System
Coordinator group. The session’s System Coordinator group is identified by the
client control System Coordinator Group Name.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Indicates the extent to which Adabas Transaction Manager will provide transaction coordination if the client session changes external databases. | YES | RM | NO | YES |
Possible values:
| Value | Description |
|---|---|
| YES | The client session is permitted to change
external RMs and external non-RMs. Adabas Transaction Manager provides DTP
coordination of external RMs using a 2-phase commit protocol. Serial
ET/BT coordination is provided for external non-RMs.
|
| RM | The client session is permitted to change external RM databases, with DTP coordination provided by ATM, as described above. If the client session attempts to change an external non-RM, the command will be rejected with RSP240/544. |
| NO | If the client session attempts to change an external RM or an external non-RM, the command will be rejected with RSP240/544. |
This feature can be used to make it easier to upgrade multi-system environments. Historically it has been difficult to perform software upgrades in sites that deploy Adabas Transaction Manager across several inter-connected systems. This client runtime control makes it possible to upgrade one system at a time. The upgrade can be achieved by creating a new System Coordinator group in one system, replacing the previous software levels. The new client control can then be used to instruct ATM to provide DTP coordination across the System Coordinator groups.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Indicates whether or not the Transaction
Manager’s TMETDATA parameter setting should be
overridden.
|
YES | NO | NO |
Possible values:
| Value | Description |
|---|---|
| YES | ET data supplied on an
ET or CL command will be
stored only in the database to which the command was issued.
|
| NO | ET data supplied on an
ET or CL command will be
stored in the location(s) indicated by the Transaction Manager’s
TMETDATA parameter.
|
For more information, see the
TMETDATA
parameter.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Indicates whether or not the ATM client proxy is
to generate an OP command when a session uses a
database without having issued an OP.
|
NO | YES | NO |
Possible values:
| Value | Description |
|---|---|
| NO | The ATM client proxy will not generate
OP commands on behalf of clients.
|
| YES | Whenever a client session uses a new database
for which no OP command has been issued, the ATM
client proxy will issue an OP command on behalf of
the client.
|
This parameter has been replaced by the TransactionModel runtime
control.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Transaction model | MESSAGE | DYNAMIC | MESSAGE |
Possible values:
| Value | Description |
|---|---|
| MESSAGE | The message-based transaction model will be
used. According to this model, a syncpoint always takes place when processing
of a message is complete (normally, this means that screen I/O causes a
syncpoint). Syncpoints caused by ET,BT,OP and
CL commands are handled in the normal way.
Unsolicited syncpoints cause ATM to commit (or back out) changes made to Adabas
databases, and release held ISNs.
|
| DYNAMIC | The dynamic transaction model will be used.
According to this model, transactions are delimited by Adabas commands.
Unsolicited commit syncpoints are ignored by ATM; ET
and CL commands cause ATM to commit pending Adabas
changes. Unsolicited rollback syncpoints cause ATM to back out changes from
Adabas databases and release held ISNs.
|
Note:
Setting TransactionModel to MESSAGE is
equivalent to SYNCMODE=FULL with ATM Version 1.2.
Note:
Setting TransactionModel to DYNAMIC is
equivalent to SYNCMODE=ADABAS with ATM Version
1.2.
Note:
There is no TransactionModel setting
equivalent to SYNCMODE=ALL with ATM Version 1.2. The
reason is that there is no distinction between the settings
SYNCMODE=ALL and SYNCMODE=FULL
with more recent versions of ATM, since ATM will always cause held ISNs to be
released when a syncpoint takes place, unless directed to do otherwise by
command options and the ExtendedHold client
control.
For more information, see also the section Syncpoint Processing Options.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Indicates whether or not a
BT command should cause ATM to request a rollback
syncpoint from the external transaction coordinator.
|
YES | NO | YES |
Possible values:
| Value | Description |
|---|---|
| YES | Any BT command will
cause ATM to request a rollback syncpoint from the external transaction
coordinator that controls the current transaction. If there is no external
transaction coordinator in use, this setting is ignored.
|
| NO | ATM will not request a rollback syncpoint from
any external coordinator when it processes a BT
command. Furthermore, if ATM itself decides that a backout must be performed,
it will not request a rollback from any external coordinator.
|
Regardless of the setting for this control, a
BT command causes all Adabas changes to be backed
out.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Indicates whether or not a
CL command should cause ATM to request a commit
syncpoint from the external transaction coordinator.
|
YES | NO | YES |
Possible values:
| Value | Description |
|---|---|
| YES | Any CL command will
cause ATM to request a commit syncpoint from the external transaction
coordinator that controls the current transaction. If there is no external
transaction coordinator in use, this setting is ignored.
|
| NO | ATM will not request a commit syncpoint from any
external coordinator when it processes a CL command.
|
For IMS TM systems for which the
HostSystemTransactionManager option is specified, a
setting of YES for the client control
GenerateExternalSyncpointOnCL will be ignored, and the
value NO will take effect.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Indicates whether or not an
ET command should cause ATM to request a commit
syncpoint from the external transaction coordinator.
|
YES | NO | YES |
Possible values:
| Value | Description |
|---|---|
| YES | Any ET command will
cause ATM to request a commit syncpoint from the external transaction
coordinator that controls the current transaction. If there is no external
transaction coordinator in use, this setting is ignored.
|
| NO | ATM will not request a commit syncpoint from any
external coordinator when it processes an ET
command.
|
Regardless of the setting for this control,
ET command causes any pending Adabas changes to be
committed.
For IMS TM systems for which the
HostSystemTransactionManager option is specified, a
setting of YES for the client control
GenerateExternalSyncpointOnET will be ignored, and the
value NO will take effect.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Indicates whether or not transactions in this client environment are to be controlled by the environment's native syncpoint manager. | YES | NO | NO |
Possible values:
| Value | Description |
|---|---|
| YES | Transactions in this client environment are to be controlled by the environment's native syncpoint manager. |
| NO | Transactions in this client environment are not to be controlled by the environment's native syncpoint manager. |
Note:
CICS under z/OS or VSE/ESA is the only client environment for which
a setting of YES is currently supported for this control.
Note:
The Client-sideTransactionManager and
HostSystemTransactionManager options are mutually
exclusive. However, setting
Client-sideTransactionManager to YES does not preclude
the use of RRMS as an external transaction coordinator for client sessions in
other jobs or TP systems, since RRMS interfaces directly with the ATM client
sessions in other jobs or TP systems and not with the client proxy
When defining client runtime controls for a CICS/RMI environment:
Setting Client-sideTransactionManager to NO
means that ATM coordinates transactions in the normal way, but not under the
control of the CICS Syncpoint Manager. That is, even when the RMI is enabled,
no transaction coordination occurs between Adabas and other RMI-enabled
resource managers.
Setting Client-sideTransactionManager to YES
activates the RMI so that the CICS Syncpoint Manager coordinates transactions
across all resource managers.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Indicates whether or not transactions in this client environment are to be controlled by the host system's native transaction manager. | YES | NO | NO |
Possible values:
| Value | Description |
|---|---|
| YES | Transactions in this client environment are to be controlled by the host system's native transaction manager. |
| NO | Transactions in this client environment are not to be controlled by the host system's native transaction manager. |
Caution:
In a z/OS system, if this control is set to YES for an
inappropriate type of job or client environment, or for a job or environment
which has not been correctly configured to use the host system’s transaction
manager, sessions executing in that job will experience response code 240,
subcode 444, and will not function correctly.
Note:
The setting of this control is effective only in z/OS systems. In
other systems, the setting is ignored.
Note:
The setting YES is currently supported only for single-user,
single-TCB batch jobs or TSO sessions, and for Com-plete and IMS TM systems,
running under z/OS.
Note:
The HostSystemTransactionManager and
Client-sideTransactionManager options are mutually
exclusive.
| Parameter Type | Use | Possible Values | Default |
|---|---|---|---|
| Client runtime | Indicates whether P and M options on
ET and BT commands will
be honored when a distributed transaction is terminated by a series of
ET or BT
commands.
|
YES | NO | NO |
Possible values:
| Value | Description |
|---|---|
| YES | P and M options on ET
and BT commands will be honored. For any application
environment in which prefetch or multifetch command options can be used, the
setting YES should be used.
|
| NO | P and M options on ET
and BT commands will not be honored.
|
If Adabas Vista is present in an application job or TP environment, the
value YES will take effect, regardless of the setting specified for the
ExtendedHold client control.
For more information on extended hold processing, see Extended Hold Processing in section Termination Commands: ET and BT.
