Writing Global Transactions

This topic includes the following sections:

• What Is a Global Transaction?

• Starting the Transaction

• Terminating the Transaction

• Terminating the Transaction

• Implicitly Defining a Global Transaction

• Defining Global Transactions for an XA-Compliant Server Group

• Testing Whether a Transaction Has Started

 

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What Is a Global Transaction?

A global transaction is a mechanism that allows a set of programming tasks, potentially using more than one resource manager and potentially executing on multiple servers, to be treated as one logical unit.

Once a process is in transaction mode, any service requests made to servers may be processed on behalf of the current transaction. The services that are called and join the transaction are referred to as transaction participants. The value returned by a participant may affect the outcome of the transaction.

A global transaction may be composed of several local transactions, each accessing the same resource manager. The resource manager is responsible for performing concurrency control and atomicity of updates. A given local transaction may be either successful or unsuccessful in completing its access; it cannot be partially successful.

A maximum of 16 server groups can participate in a single transaction.

The BEA Tuxedo system manages a global transaction in conjunction with the participating resource managers and treats it as a specific sequence of operations that is characterized by atomicity, consistency, isolation, and durability. In other words, a global transaction is a logical unit of work in which:

• All portions either succeed or have no effect.

• Operations are performed that correctly transform resources from one consistent state to another.

• Intermediate results are not accessible to other transactions, although some processes in a transaction may access the data associated with another process.

• Once a sequence is complete, its results cannot be altered by any kind of failure.

The BEA Tuxedo system tracks the status of each global transaction and determines whether it should be committed or rolled back.

 

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Starting the Transaction

To start a global transaction, use the TPBEGIN(3cbl) routine with the following signature:

*
  01 TPTRXDEF-REC.
     COPY TPTRXDEF.
*
  01 TPSTATUS-REC.
     COPY TPSTATUS.
*
   CALL "TPBEGIN" USING TPTRXDEF-REC TPSTATUS-REC.

The following table describes the TPTRXDEF-REC structure fields

Table 9-1 TPTRXDEF Structure Field

Field	Description
T-OUT	Specifies the amount of time, in seconds, a transaction can execute before timing out. You can set this value to the maximum number of seconds allowed by the system, by specifying a value of 0. In other words, you can set timeout to the maximum value for an unsigned long as defined by the system. The use of 0 or an unrealistically large value for the T-OUT parameter delays system detection and reporting of errors. The system uses the T-OUT parameter to ensure that responses to service requests are sent within a reasonable time, and to terminate transactions that encounter problems such as network failures before executing a commit. For a transaction in which a person is waiting for a response, you should set this parameter to a small value: if possible, less than 30 seconds. In a production system, you should set T-OUT to a value large enough to accommodate expected delays due to system load and database contention. A small multiple of the expected average response time is often an appropriate choice. Note: The value assigned to the T-OUT parameter should be consistent with that of the SCANUNIT parameter set by the BEA Tuxedo application administrator in the configuration file. The SCANUNIT parameter specifies the frequency with which the system checks, or scans, for timed-out transactions and blocked calls in service requests. The value of this parameter represents the interval of time between these periodic scans, referred to as the scanning unit. You should set the T-OUT parameter to a value that is greater than the scanning unit. If you set the T-OUT parameter to a value smaller than the scanning unit, there will be a discrepancy between the time at which a transaction times out and the time at which this timeout is discovered by the system. The default value for SCANUNIT is 10 seconds. You may need to discuss the setting of the T-OUT parameter with your application administrator to make sure the value you assign to the T-OUT parameter is compatible with the values assigned to your system parameters.
TRANID	Transaction identifier.

Any process may call TPBEGIN unless the process is already in transaction mode. If TPBEGIN is called in transaction mode, the call fails due to a protocol error and TP-STATUS is set to TPEPROTO. If the process is in transaction mode, the transaction is unaffected by the failure.

The following example provides a high-level view of how a global transaction is defined.

Listing 9-1 Delineating a Transaction

. . .
MOVE 0 TO T-OUT.
CALL "TPBEGIN" USING
TPTRXDEF-REC
TPSTATUS-REC.
IF  NOT TPOK
    error processing
. . .
    program statements
. . .
CALL "TPCOMMIT" USING
                TPTRXDEF-REC
                TPSTATUS-REC.
IF  NOT TPOK
    error processing

The following example shows how an outstanding reply can cause an error.

Listing 9-2 Error - Starting a Transaction with an Outstanding Reply

  . . .
  MOVE "BUY" TO SERVICE-NAME.
  SET TPBLOCK TO TRUE.
  SET TPNOTRAN TO TRUE.
  SET TPREPLY TO TRUE.
  SET TPNOTIME TO TRUE.
  SET TPSIGRSTRT TO TRUE.
  CALL "TPACALL" USING
                 TPSVCDEF-REC
                 TPTYPE-REC
                 BUY-REC
                 TPSTATUS-REC.
  IF  NOT TPOK
      error processing
  . . .
  MOVE 0 TO T-OUT.
  CALL "TPBEGIN" USING
                 TPTRXDEF-REC
                 TPSTATUS-REC.
  IF  NOT TPOK
      error processing
* ERROR TP-STATUS is set to TPEPROTO
  . . .
      program statements
  . . .
  SET TPBLOCK TO TRUE.
  SET TPNOTRAN TO TRUE.
  SET TPCHANGE TO TRUE.
  SET TPNOTIME TO TRUE.
  SET TPSIGRSTRT TO TRUE.
  SET TPGETANY TO TRUE.
  CALL "TPGETRPLY" USING
                   TPSVCDEF-REC
                   TPTYPE-REC
                   WK-AREA
                   TPSTATUS-REC.
  IF  NOT TPOK
      error processing

If a transaction times out, a call to TPCOMMIT causes the transaction to be aborted. As a result, TPCOMMIT fails and sets TP-STATUS to TPEABORT.

The following example shows how to test for a transaction timeout. Note that the value of T-OUT is set to 30 seconds.

Listing 9-3 Testing for Transaction Timeout

. . .
MOVE 30 TO T-OUT.
CALL "TPBEGIN" USING TPTRXDEF-REC TPSTATUS-REC.
IF  NOT TPOK
    MOVE "Failed to BEGIN a transaction" TO LOG-REC-TEXT.
    MOVE 29 to LOG-REC-LEN
    CALL "USERLOG" USING
                   LOG-REC-TEXT
                   LOG-REC-LEN
                   TPSTATUS-REC
    CALL "TPTERM" USING
                  TPSTATUS-REC
    PERFORM A-999-EXIT.
. . .
       communication CALL statements
. . .
IF  TPETIME
    CALL "TPABORT" USING
                   TPTRXDEF-REC
                   TPSTATUS-REC
IF  NOT TPOK
       error processing
ELSE
   CALL "TPCOMMIT" USING
                   TPTRXDEF-REC
                   TPSTATUS-REC
   IF  NOT TPOK
        error processing

Note: When a process is in transaction mode and makes a communication call with TPNOTRAN, it prohibits the called service from becoming a participant in the current transaction. Whether the service request succeeds or fails has no impact on the outcome of the transaction. The transaction can still timeout while waiting for a reply that is due from a service, whether it is part of the transaction or not. Refer to "Managing Errors" on page 11-1 for more information on the effects of the TPNOTRAN flag.

The following example shows how to define a transaction.

Listing 9-4 Defining a Transaction

 DATA DIVISION.
 WORKING-STORAGE SECTION.
*
 01  TPTYPE-REC.
 COPY TPTYPE.
*
 01 TPSTATUS-REC.
 COPY TPSTATUS.
*
 01 TPINFDEF-REC.
 COPY TPINFDEF.
*
 01  TPSVCDEF-REC.
 COPY TPSVCDEF.
*
 01  TPTRXDEF-REC.
 COPY TPTRXDEF.
*
 01 LOG-REC              PIC X(30) VALUE " ".
 01 LOG-REC-LEN          PIC S9(9)  COMP-5.
*
 01 USR-DATA-REC         PIC X(16).
*
 01 AUDV-REC.
     05  AUDV-BRANCH-ID      PIC S9(9) COMP-5.
     05  AUDV-BALANCE        PIC S9(9) COMP-5.
     05  AUDV-ERRMSG         PIC X(60).
*
 PROCEDURE DIVISION.
*
 A-000.
  . . .
* Get Command Line Options  set Variables (Q-BRANCH)
  MOVE SPACES TO USRNAME.
  MOVE SPACES TO CLTNAME.
  MOVE SPACES TO PASSWD.
  MOVE SPACES TO GRPNAME.
  CALL "TPINITIALIZE" USING TPINFDEF-REC
                      USR-DATA-REC
                      TPSTATUS-REC.
  IF  NOT TPOK
      MOVE "Failed to join application" TO LOG-REC
      MOVE 26 TO LOG-REC-LEN
       CALL "USERLOG" USING LOG-REC
                      LOG-REC-LEN
                      TPSTATUS-REC
       PERFORM A-999-EXIT.
* Start global transaction
  MOVE 30 TO T-OUT.
  CALL "TPBEGIN" USING TPTRXDEF-REC TPSTATUS-REC.
  IF  NOT TPOK
      MOVE 29 to LOG-REC-LEN
      MOVE "Failed to begin a transaction" TO LOG-REC
      CALL "USERLOG" USING LOG-REC
                     LOG-REC-LEN
                     TPSTATUS-REC
      PERFORM DO-TPTERM.
* Set up record
  MOVE Q-BRANCH TO AUDV-BRANCH-ID.
  MOVE ZEROS TO AUDV-BALANCE.
  MOVE SPACES TO AUDV-ERRMSG.
* Set up TPCALL records
  MOVE "GETBALANCE" TO SERVICE-NAME.
  MOVE "VIEW" TO REC-TYPE.
  MOVE LENGTH OF AUDV-REC TO LEN.
  SET TPBLOCK TO TRUE.
  SET TPTRAN IN TPSVCDEF-REC TO TRUE.
  SET TPNOTIME TO TRUE.
  SET TPSIGRSTRT TO TRUE.
  SET TPCHANGE TO TRUE.
*
  CALL "TPCALL" USING TPSVCDEF-REC
                TPTYPE-REC
                AUDV-REC
                TPTYPE-REC
                AUDV-REC
                TPSTATUS-REC.
  IF  NOT TPOK
      MOVE 19 to LOG-REC-LEN
      MOVE "Service call failed" TO LOG-REC
      CALL "USERLOG" USING LOG-REC
                     LOG-REC-LEN
                     TPSTATUS-REC
      PERFORM DO-TPABORT
      PERFORM DO-TPTERM.
* Commit global transaction
  CALL "TPCOMMIT" USING TPTRXDEF-REC
                  TPSTATUS-REC
  IF  NOT TPOK
      MOVE 16 to LOG-REC-LEN
      MOVE "Failed to commit" TO LOG-REC
      CALL "USERLOG" USING LOG-REC
                LOG-REC-LEN
                TPSTATUS-REC
      PERFORM DO-TPTERM.
* Show results only when transaction has completed successfully
  DISPLAY "BRANCH=" Q-BRANCH.
  DISPLAY "BALANCE=" AUDV-BALANCE.
  PERFORM DO-TPTERM.
* Abort the transaction
 DO-TPABORT.
  CALL "TPABORT" USING TPTRXDEF-REC
                 TPSTATUS-REC
  IF  NOT TPOK
      MOVE 26 to LOG-REC-LEN
      MOVE "Failed to abort transaction" TO LOG-REC
      CALL "USERLOG" USING LOG-REC
                     LOG-REC-LEN
                     TPSTATUS-REC.
* Leave the application
 DO-TPTERM.
  CALL "TPTERM" USING TPSTATUS-REC.
  IF  NOT TPOK
      MOVE 27 to LOG-REC-LEN
      MOVE "Failed to leave application" TO LOG-REC
      CALL "USERLOG" USING LOG-REC
                     LOG-REC-LEN
                     TPSTATUS-REC.
                     EXIT PROGRAM.
*
 A-999-EXIT.
*
 EXIT PROGRAM.

 

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Terminating the Transaction

To end a global transaction, call TPCOMMIT(3cbl) to commit the current transaction, or TPABORT(3cbl) to abort the transaction and roll back all operations.

Note: If TPCALL, TPACALL, or TPCONNECT is called by a process that has explicitly set TPNOTRAN, the operations performed by the called service do not become part of the current transaction. In other words, when you call the TPABORT routine, the operations performed by these services are not rolled back.

Committing the Current Transaction

The TPCOMMIT(3cbl) routine commits the current transaction. When TPCOMMIT returns successfully, all changes to resources as a result of the current transaction become permanent.

Use the following signature to call the TPCOMMIT routine:

*
  01 TPTRXDEF-REC.
     COPY TPTRXDEF.
*
  01 TPSTATUS-REC.
     COPY TPSTATUS.
*
   CALL "TPCOMMIT" USING TPTRXDEF-REC TPSTATUS-REC.

Refer to Starting the Transaction for a description of the TPTRXDEF-REC structure.

Prerequisites for a Transaction Commit

For TPCOMMIT to succeed, the following conditions must be true:

• The calling process must be the same one that initiated the transaction with a call to TPBEGIN.

• The calling process must have no transactional replies (calls made without the TPNOTRAN flag) outstanding.

• The transaction must not be in a rollback-only state and must not be timed out.

If the first condition is false, the call fails and TP-STATUS is set to TPEPROTO, indicating a protocol error. If the second or third condition is false, the call fails and TP-STATUS is set to TPEABORT, indicating that the transaction has been rolled back. If TPCOMMIT is called by the initiator with outstanding transaction replies, the transaction is aborted and those reply descriptors associated with the transaction become invalid. If a participant calls TPCOMMIT or TPABORT, the transaction is unaffected.

A transaction is placed in a rollback-only state if any service call returns TPFAIL or indicates a service error. If TPCOMMIT is called for a rollback-only transaction, the routine cancels the transaction, returns -1, and sets TP-STATUS to TPEABORT. The results are the same if TPCOMMIT is called for a transaction that has already timed out: TPCOMMIT returns -1 and sets TP-STATUS to TPEABORT. Refer to "Managing Errors" on page 11-1 for more information on transaction errors.

Two-phase Commit Protocol

When the TPCOMMIT routine is called, it initiates the two-phase commit protocol. This protocol, as the name suggests, consists of two steps:

1. Each participating resource manager indicates a readiness to commit.

2. The initiator of the transaction gives permission to commit to each participating resource manager.

The commit sequence begins when the transaction initiator calls the TPCOMMIT routine. The BEA Tuxedo TMS server process in the designated coordinator group contacts the TMS in each participant group that is to perform the first phase of the commit protocol. The TMS in each group then instructs the resource manager (RM) in that group to commit using the XA protocol that is defined for communications between the Transaction Managers and RMs. The RM writes, to stable storage, the states of the transaction before and after the commit sequence, and indicates success or failure to the TMS. The TMS then passes the response back to the coordinating TMS.

When the coordinating TMS has received a success indication from all groups, it logs a statement to the effect that a transaction is being committed and sends second-phase commit notifications to all participant groups. The RM in each group then finalizes the transaction updates.

If the coordinator TMS is notified of a first-phase commit failure from any group, or if it fails to receive a reply from any group, it sends a rollback notification to each RM and the RMs back out all transaction updates. TPCOMMIT then fails and sets TP-STATUS to TPEABORT.

Selecting Criteria for a Successful Commit

When more than one group is involved in a transaction, you can specify which of two criteria must be met for TPCOMMIT to return successfully:

• When all participants have indicated a readiness to commit (that is, when all participants have reported that phase 1 of the two-phase commit has been logged as complete and the coordinating TMS has written its decision to commit to stable storage)

• When all participants have finished phase 2 of the two-phase commit

To specify one of these prerequisites, set the CMTRET parameter in the RESOURCES section of the configuration file to one of the following values:

• LOGGED—to require completion of phase 1

• COMPLETE—to require completion of phase 2

By default, CMTRET is set to COMPLETE.

Trade-offs Between Possible Commit Criteria

In most cases, when all participants in a global transaction have logged successful completion of phase 1, they do not fail to complete phase 2. By setting CMTRET to LOGGED, you allow a slightly faster return of calls to TCOMMIT, but you run the slight risk that a participant may heuristically complete its part of the transaction in a way that is not consistent with the commit decision.

Whether it is prudent to accept the risk depends to a large extent on the nature of your application. If your application demands complete accuracy (for example, if you are running a financial application), you should probably wait until all participants fully complete the two-phase commit process before returning. If your application is more time-sensitive, you may prefer to have the application execute faster at the expense of accuracy.

Aborting the Current Transaction

Use the TPABORT(3cbl) routine to indicate an abnormal condition and explicitly abort a transaction. This function invalidates the call descriptors of any outstanding transactional replies. None of the changes produced by the transaction are applied to the resource. Use the following signature to call the TPABORT routine:

*
  01 TPTRXDEF-REC.
     COPY TPTRXDEF.
*
  01 TPSTATUS-REC.
     COPY TPSTATUS.
*
   CALL "TPABORT" USING TPTRXDEF-REC TPSTATUS-REC.

Refer to Starting the Transaction for a description of the TPTRXDEF-REC structure.

Example: Committing a Transaction in Conversational Mode

The following figure illustrates a conversational connection hierarchy that includes a global transaction.

Figure 9-1 Connection Hierarchy in Transaction Mode

 

The connection hierarchy is created through the following process:

1. A client (process A) initiates a connection in transaction mode by calling TPBEGIN and TPCONNECT.

2. The client calls subsidiary services, which are executed.

3. As each subordinate service completes, it sends a reply indicating success or failure (TPEV_SVCSUCC or TPEV_SVCFAIL, respectively) back up through the hierarchy to the process that initiated the transaction. In this example the process that initiated the transaction is the client (process A). When a subordinate service has completed sending replies (that is, when no more replies are outstanding), it must call TPRETURN.

4. The client (process A) determines whether all subordinate services have returned successfully.

   • If so, the client commits the changes made by those services, by calling TPCOMMIT, and completes the transaction.

   • If not, the client calls TPABORT, since it knows that TPCOMMIT could not be successful.

Example: Testing for Participant Errors

In the following sample code, a client makes a synchronous call to the fictitious REPORT service (line 24). Then the code checks for participant failures by testing for errors that can be returned on a communication call (lines 30-42).

Listing 9-5 Testing for Participant Success or Failure

01   . . .
02   CALL "TPINITIALIZE" USING TPINFDEF-REC
03   USR-DATA-REC
04   TPSTATUS-REC.
05   IF  NOT TPOK
06       error message,
07       EXIT PROGRAM .
08   MOVE 30 TO T-OUT.
09   CALL "TPBEGIN" USING TPTRXDEF-REC TPSTATUS-REC.
10   IF  NOT TPOK
11       error message,
12       PERFORM DO-TPTERM.
13  * Set up record
14   MOVE "REPORT=accrcv DBNAME=accounts" TP-RECORD.
15   MOVE 27 TO LEN.
16   MOVE "REPORTS" TO SERVICE-NAME.
17   MOVE "STRING" TO REC-TYPE.
18   SET TPBLOCK TO TRUE.
19   SET TPTRAN IN TPSVCDEF-REC TO TRUE.
20   SET TPNOTIME TO TRUE.
21   SET TPSIGRSTRT TO TRUE.
22 SET TPCHANGE TO TRUE.
23  *
24   CALL "TPCALL" USING TPSVCDEF-REC
25                 TPTYPE-REC
26                 TP-RECORD
27                 TPTYPE-REC
28                 TP-RECORD
29                 TPSTATUS-REC.
30   IF  TPOK
31        PERFORM DO-TPCOMMIT
32        PERFORM DO-TPTERM.
33  * Check return status
34    IF  TPESVCERR
35    DISPLAY "REPORT service's TPRETURN encountered problems"
36    ELSE IF  TPESVCFAIL
37    DISPLAY "REPORT service FAILED with return code=" APPL-RETURN-CODE
38    ELSE IF  TPEOTYPE
39    DISPLAY "REPORT service's reply is not of any known REC-TYPE"
40  *
41    PERFORM DO-TPABORT
42    PERFORM DO-TPTERM.
43  * Commit global transaction
44   DO-TPCOMMIT.
45    CALL "TPCOMMIT" USING TPTRXDEF-REC
46                    TPSTATUS-REC
47    IF  NOT TPOK
48        error message
49  * Abort the transaction
50   DO-TPABORT.
51    CALL "TPABORT" USING TPTRXDEF-REC
52                   TPSTATUS-REC
53    IF  NOT TPOK
54        error message
55  * Leave the application
56   DO-TPTERM.
57    CALL "TPTERM" USING TPSTATUS-REC.
58    IF  NOT TPOK
59        error message
60    EXIT PROGRAM.

 

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Implicitly Defining a Global Transaction

An application can start a global transaction in either of two ways:

• Explicitly, by calling ATMI calls, as described in Starting the Transaction.

• Implicitly, from within a service routine

This section describes the second method.

You can implicitly place a service routine in transaction mode by setting the system parameter AUTOTRAN in the configuration file. If you set AUTOTRAN to Y, the system automatically starts a transaction in the service subroutine when a request is received from another process.

When implicitly defining a transaction, observe the following rules:

• If a process requests a service from another process when the calling process is not in transaction mode and the AUTOTRAN system parameter is set to start a transaction, the system initiates a transaction.

• If a process that is already in transaction mode requests a service from another process, the system's first response is to determine whether or not the caller is set to TPNOTRAN.

  If not set to TPNOTRAN, then the system places the called process in transaction mode through the "rule of propagation." The system does not check the AUTOTRAN parameter.

  If TPTRN-FLAG IN TPSVCDEF-REC is set to TPNOTRAN, the services performed by the called process are not included in the current transaction (that is, the propagation rule is suppressed). The system checks the AUTOTRAN parameter.

  • If AUTOTRAN is set to N (or if it is not set), the system does not place the called process in transaction mode.

  • If AUTOTRAN is set to Y, the system places the called process in transaction mode, but treats it as a new transaction.

Note: Because a service can be placed in transaction mode automatically, it is possible for a service with the TPNOTRAN flag set to call services that have the AUTOTRAN parameter set. If such a service requests another service, the member of the service information structure returns TPTRAN when queried. For example, if the call is made with TPNOTRAN | TPNOREPLY, and the service automatically starts a transaction when called, the information structure is set to TPTRAN | TPNOREPLY.

 

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Defining Global Transactions for an XA-Compliant Server Group

Generally, the application programmer writes a service that is part of an XA-compliant server group to perform some operation via the group's resource manager. In the normal case, the service expects to perform all operations within a transaction. If, on the other hand, the service is called with the communication setting of TPNOTRAN, you may receive unexpected results when executing database operations.

In order to avoid unexpected behavior, design the application so that services in groups associated with XA-compliant resource managers are always called in transaction mode or are always defined in the configuration file with AUTOTRAN set to Y. You should also test the transaction level in the service code early.

 

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Testing Whether a Transaction Has Started

It is important to know whether or not a process is in transaction mode in order to avoid and interpret certain error conditions. For example, it is an error for a process already in transaction mode to call TPBEGIN. When TPBEGIN is called by such a process, it fails and sets TP-STATUS to TPEPROTO to indicate that it was invoked while the caller was already participating in a transaction. The transaction is not affected.

You can design a service subroutine so that it tests whether it is in transaction mode before invoking TPBEGIN. You can test the transaction level by either of the following methods:

• Querying the settings of the service information structure that is passed to the service routine. The service is in transaction mode if the value is set to TPTRAN.

• Calling the TPGETLEV(3cbl) routine.

Use the following signature to call the TPGETLEV routine:

01 TPTRXLEV-REC.
   COPY TPTRXLEV.
01 TPSTATUS-REC.
   COPY TPSTATUS.
CALL "TPGETLEV" USING TPTRXLEV-REC TPSTATUS-REC.

TPGETLEV returns TP-NOT-IN-TRAN if the caller is not in a transaction and TP-IN-TRAN if the caller is.

The following code sample shows how to test for transaction level using the TPGETLEV routine (line 3). If the process is not already in transaction mode, the application starts a transaction (line 5). If TPBEGIN fails, a message is returned to the status line (line 9) and APPL-CODE IN TPSVCRET-REC of TPRETURN is set to a code that can be retrieved in APL-RETURN-CODE IN TPSTATUS-REC (lines 1 and 11).

Listing 9-6 Testing Transaction Level

     . . . Application defined codes
001      77 BEG-FAILED    PIC S9(9) VALUE 3.
     . . .
002  PROCEDURE DIVISION.
     . . .
003  CALL "TPGETLEV" USING TPTRCLEV-REC
                     TPSTATUS-REC.
004  IF NOT TPOK
        error processing  EXIT PROGRAM
005  IF TP-NOT-IN-TRAN
006         MOVE 30 TO T-OUT.
007         CALL "TPBEGIN" USING
                           TPTRXDEF-REC
                           TPSTATUS-REC.
008         IF  NOT TPOK
009              MOVE "Attempt to TPBEGIN within service failed"
                           TO USER-MESSAGE.
010              SET TPFAIL TO TRUE.
011              MOVE BEG-FAILED TO APPL-CODE.
012              COPY TPRETURN REPLACING
013                        DATA-REC BY USER-MESSAGE.
     . . .

If the AUTOTRAN parameter is set to Y, you do not need to call the TPBEGIN, and TPCOMMIT or TPABORT transaction routines explicitly. As a result, you can avoid the overhead of testing for transaction level. In addition, you can set the TRANTIME parameter to specify the time-out interval: the amount of time that may elapse after a transaction for a service begins, and before it is rolled back if not completed.

For example, suppose you are revising the OPEN_ACCT service shown in the preceding code listing. Currently, OPEN_ACCT defines the transaction explicitly and then tests for its existence. To reduce the overhead introduced by these tasks, you can eliminate them from the code. Therefore, you need to require that whenever OPEN_ACCT is called, it is called in transaction mode. To specify this requirement, enable the AUTOTRAN and TRANTIME system parameters in the configuration file.

See Also

• Description of the AUTOTRAN configuration parameter in the section Implicitly Defining a Global Transaction of Setting Up a BEA Tuxedo Application.

• TRANTIME configuration parameter in Setting Up a BEA Tuxedo Application.