topic Recommended retry for ENQUEUE process in Application Development and Automation Discussions

Recommended retry for ENQUEUE process

suwandi_cahyadi — Tue, 05 Aug 2014 11:41:35 GMT

Hi Experts,

I'm planning to put a retry when failing to get a lock object in my ABAP program.

I know that we can use the _wait parameter in FM. But I prefer to use a custom wait-time and max-retry, so I plan to call the ENQUEUE FM inside a DO.x TIMES. ENDDO.

But I'm afraid that calling ENQUEUE too many times could eat too much resource or impact in bad performance. (According to the basis team, the enque/table_size is configured as recommended by SAP, an so far it is still enough)

Is a 2 seconds interval, up to 30 times (results in max 1 minute wait before giving up getting the lock) is a worrying number?

Is it true that calling ENQUEUE too many times could result in SAP lock table overflow even if the lock is not acquired?

Thank you,

Suwandi C.

Re: Recommended retry for ENQUEUE process

Former Member — Tue, 05 Aug 2014 15:29:40 GMT

Hi,

i think 30 table reads a min is no performance problem...

during migration we set alot enqueues. and we did without wait statement still the rest of the system worked fine.

regards

Stefan Seeburger

Re: Recommended retry for ENQUEUE process

naimesh_patel — Tue, 05 Aug 2014 15:29:40 GMT

The Lock table overflow can only occur if the locks are not getting released. Like if you have program where you are updating 1M records. If your program is like this:

Lock all 1M records
Process the records and update the table
Unlock all 1M records

In this instance, the lock table overflow can occur if the lock table can't hold 1M records.

When you implement the DO.. ENQUEUE.. ENDDO, the lock table overflow can't occur, if you implement it properly. It should be implemented like:

DO n times

call ENQUEUE FM

if sy-subrc eq 0.

locked = 'x'

EXIT

else.

WAIT UP TO 1 SECOND

endif.

Enddo.

if locked = 'x'

call DEQUEUE FM

call BAPI to update

else

error handling, lock not applied

endif.

If you should put the loop time and wait second, in configurable table say TVARVC so it can be controlled easily.

In this instance, you would always have only 1 entry in your lock table, When you try to lock it again using the ENQUEUE FM and if it fails, there is an existing lock entry. if it succeed, you would have a new lock entry.

Regards,
Naimesh Patel