Call transaction and session method

[prabhu_s2]

Hi All

what does the following phrase imply:

<b>1. The system performs a database commit immediately before and after the CALL TRANSACTION USING statement</b>

and

<b>2. what does sync and async processing mean in session and call transaction.</b>

can an example be sited for the above?

[Former Member]

Hi

Asynchronous Update – The program does not wait for the work process to finish the update. Commit Work.

Synchronous Update – The program wait for the work process to finish the update. Commit Work and Wait.

Asynchronous updating. In this mode, the called transaction does not wait for any updates it produces to be completed. It simply passes the updates to the SAP update service. Asynchronous processing therefore usually results in faster execution of your data transfer program.

Asynchronous processing is NOT recommended for processing any larger amount of data. This is because the called transaction receives no completion message from the update module in asynchronous updating. The calling data transfer program, in turn, cannot determine whether a called transaction ended with a successful update of the database or not.

If you use asynchronous updating, then you will need to use the update management facility (Transaction SM12) to check whether updates have been terminated abnormally during session processing. Error analysis and recovery is less convenient than with synchronous updating.

Synchronous updating. In this mode, the called transaction waits for any updates that it produces to be completed. Execution is slower than with asynchronous updating because called transactions wait for updating to be completed. However, the called transaction is able to return any update error message that occurs to your program. It is much easier for you to analyze and recover from errors.

BDC:

Batch Data Communication (BDC) is the process of transferring data from one SAP System to another SAP system or from a non-SAP system to SAP System.

Features :

BDC is an automatic procedure.

This method is used to transfer large amount of data that is available in electronic medium.

BDC can be used primarily when installing the SAP system and when transferring data from a legacy system (external system).

BDC uses normal transaction codes to transfer data.

Types of BDC :

CLASSICAL BATCH INPUT (Session Method)

CALL TRANSACTION

BATCH INPUT METHOD:

This method is also called as ‘CLASSICAL METHOD’.

Features:

Asynchronous processing.

Synchronous Processing in database update.

Transfer data for more than one transaction.

Batch input processing log will be generated.

During processing, no transaction is started until the previous transaction has been written to the database.

CALL TRANSACTION METHOD :

This is another method to transfer data from the legacy system.

Features:

Synchronous processing. The system performs a database commit immediately before and after the CALL TRANSACTION USING statement.

Updating the database can be either synchronous or asynchronous. The program specifies the update type.

Transfer data for a single transaction.

Transfers data for a sequence of dialog screens.

No batch input processing log is generated.

For BDC:

http://myweb.dal.ca/hchinni/sap/bdc_home.htm

https://www.sdn.sap.com/irj/sdn/wiki?path=/display/home/bdc&;

http://www.sap-img.com/abap/learning-bdc-programming.htm

http://www.sapdevelopment.co.uk/bdc/bdchome.htm

http://www.sap-img.com/abap/difference-between-batch-input-and-call-transaction-in-bdc.htm

http://help.sap.com/saphelp_47x200/helpdata/en/69/c250684ba111d189750000e8322d00/frameset.htm

http://www.sapbrain.com/TUTORIALS/TECHNICAL/BDC_tutorial.html

Check these link:

http://www.sap-img.com/abap/difference-between-batch-input-and-call-transaction-in-bdc.htm

http://www.sap-img.com/abap/question-about-bdc-program.htm

http://www.itcserver.com/blog/2006/06/30/batch-input-vs-call-transaction/

http://www.planetsap.com/bdc_main_page.htm

Reward points if useful

Regards

Anji

[Former Member]

Hi,

<b>Synchronous Update :</b> This means say if u have 10 records to update and the processing is going on in a loop the Synchronous update will wait till each update is actually done in the data base and then it will move on the next record's updation.

<b>Asynchronous :</b> In This mode, the updates are lined one after the other and the system doesn't wait for the updates to actually happen. These updates are then triggered by an internally scheduled job which then actually updates the data in the databse.

Regards

Sudheer

[prabhu_s2]

sudhir,

do only when the record is updated in the DB the processing of next record happenss?

Message was edited by:

Prabhu S

[Former Member]

Hi,

Asynchronous Update – The program does not wait for the work process to finish the update. Commit Work.

Synchronous Update – The program wait for the work process to finish the update. Commit Work and Wait.

Regards,

Kishor

[sreeramkumar_madisetty]

Hi

Have a look on these links:

For BDC:

http://myweb.dal.ca/hchinni/sap/bdc_home.htm

https://www.sdn.sap.com/irj/sdn/wiki?path=/display/home/bdc&;

http://www.sap-img.com/abap/learning-bdc-programming.htm

http://www.sapdevelopment.co.uk/bdc/bdchome.htm

http://www.sap-img.com/abap/difference-between-batch-input-and-call-transaction-in-bdc.htm

http://help.sap.com/saphelp_47x200/helpdata/en/69/c250684ba111d189750000e8322d00/frameset.htm

http://www.sapbrain.com/TUTORIALS/TECHNICAL/BDC_tutorial.html

Check these link:

http://www.sap-img.com/abap/difference-between-batch-input-and-call-transaction-in-bdc.htm

http://www.sap-img.com/abap/question-about-bdc-program.htm

http://www.itcserver.com/blog/2006/06/30/batch-input-vs-call-transaction/

http://www.planetsap.com/bdc_main_page.htm

Regards,

Sreeram

[prabhu_s2]

sree ram

i do have those links. but can u give some tips and ur thoughts on this?

[Former Member]

Hi Prabhu,

Call transaction can be executed in sync or asynch processing,

in synchronus update, system waits for response after passing the record to screen and then only after getting response saying that record is updated,then only second record will go into the screen.

it mean Synchronus is 2ways .

while in asynchronus updates, process does not wait for response. it just passes the records to screen one after the another waitout waiting for response.

it mean asynchronus is 1 way.

reward if helpful

regards,

naveen

[prabhu_s2]

naveen,

in async mode only when all the records are processed the commit happens?

[Former Member]

Hi

records will be comitted record by record only

but there is no gurrantee that each and every record was successfully committed or not in Async process.

Reward points if useful

Regards

Anji

[prabhu_s2]

thks guys. the discuission was indeed helpful

[hymavathi_oruganti]

1) The system automatically performs database commit before and after any executable statement. not only call transaction.

this is the concept of <b>LUW</b>.

LUW concept is based on <b>ALL OR NONE</b>

concept. which means either all are commited or none are commited.

means if any error comes in the middle nothing is committed.

in a trasaction, at the end of every screen also, system automatically performs dbcommit.

we can give our own explicit commit with the "<b>COMMIT WORK</b>" statement.

this is called SAP COMMIT.

we can bypass the DB COMMITS until SAP COMMIT reaches by using update bundling techniques.

2) <b>synchronous updation</b> waits for the update work process to complete its work

and then proceeds with the next updation.

<b>asynchrounous updation</b> is faster as it does not wait for the update work process

to complete its work and proceeds. but this is not safer as some may fail in the middle. but if we need faster updation we can go for this option.

coming to<b> synchronous and asynchronous processing,</b>

<b>session method uses asynchronous processing and synchronous updation</b>.

processing is called asynchronous in a session method because it does not return sy-subrc. so we does not know wheher succeded or not but processing continues.

<b>call transaction method uses synchronous processing</b> and updation we can select any option.

call transaction returns sy-subrc so, it is synchronous.

sy