sync & Async process?

[Former Member]

hi!

we know in bdc that call transaction is synchronous process and session method is asynchronous process.

can anybody explain what's this synchronous and asynchronous process mean?

[Former Member]

Hai Ravi,

Synchronous process - In call transaction, you can perform the BDC process executes by the way you have coded, it cannot be changed

Asynchronous process - In session method, you can create n sessions at a time and execute them in any order not in the creation order.

[Former Member]

Synchronous calls are slower but should be used for transactions that are updating the database because control is not passed back to the program until a successful database commit (or rollback) has been executed. Note this the real SQL commit at the database level not the ABAP command COMMIT WORK. Synchronous calls will set the return code (sy-subrc) if an error is encountered. There are actually two synchrounous update modes:

'S', Synchronous update mode makes database entries describing the updates to be done and an update task (potentially running on a different computer) reads those database entries, does the update, and then deletes the entries describing the update task.

'L', Local update mode describes the updates to be done in the memory of the current process. No entries are made in and then deleted from the database describing the update task.

Asynchronous calls are the default if the UPDATE parameter is not specified. Asynchronous calls do not effect the return code (sy-subrc).

Note - This is opposite of how synchronous/asynchronous workflow tasks behave, in the sense that control is returned to the workflow in a synchronous step even if there is no commit or rollback encountered!

Question - Does a synchronous call transaction cause the ABAP to issue a COMMIT WORK AND WAIT command within the transaction