What type of delta does LO run ?

Question

Hi.. I understand that in COPA extraction there are no migration steps involved as it runs on "time stamp delta". If that is the case then please let me know what type of delta does LO and LIS run... If even LO and LIS run on time stamp then please let me know why are there no migration steps involved in COPA...?

Answer 1

Logistic's Area use's three Types of Delta Mechanism's :
1. Direct Delta
2. Queued Delta
3. Un-serialized V3 Update
These are different work processes on the application server that takes the update LUW (which may have various DB manipulation SQLs) from the running program and execute it. These are separated to optimize transaction processing capabilities.
Taking an example -
If you create/change a purchase order (me21n/me22n), when you press 'SAVE' and see a success message (PO.... changed..), the update to underlying tables EKKO/EKPO has happened (before you saw the message). This update was executed in the V1 work process.
There are some statistics collecting tables in the system which can capture data for reporting. For example, LIS table S012 stores purchasing data (it is the same data as EKKO/EKPO stored redundantly, but in a different structure to optimize reporting). Now, these tables are updated with the txn you just posted, in a V2 process. Depending on system load, this may happen a few seconds later (after you saw the success message). You can see V1/V2/V3 queues in SM12 or SM13.
In a local update, the update program is run by the same work process that processed the request. The dialog user has to wait for the update to finish before entering further data. This kind of update is useful when you want to reduce the amount of access to the database. The disadvantage of local updates is their parallel nature. The updates can be processed by many different work processes, unlike asynchronous or synchronous update, where the update is serialized due to the fact that there are fewer update work processes (and maybe only one).