Lock strategies in S/4HANA 1610
In S/4HANA 1610 the following features are available which increases the throughput of goods movement postings.
No Locks on both Standard and Moving Average price materials,
With SAP S/4HANA, on-premise edition 1610, no exclusive locking is required anymore for material valuation, this comprises materials with price control “Moving Average” and all special stock types as HANA is an Insert-only Database. This enables parallel material document processing.
As the new MM-IM data model changes the old key figure model to an account model(53 additional columns for fast calculations / analytics) this enables a more finer granular locking for the late quantity lock case starting with S/4HANA OP1610 and CE1608.
Below is an example for a Key figure model & Account model,
Key figure model,
For the key figure model the locks have been set on material and plant level in
S/4HANAOP1511. With the account model the locks can be set on material, plant, storage
location, stock identifier, special stock identifier level (in principle what defines the stock in the
new model) starting with S/4HANA OP1610 and CE1608. Hence, even in parallel processes the probability for a lock collision is rather likely.
Exceptional locking in Moving Average price,
When a goods movement changes the ratio between the stock value (SALK3) and the valuated stock quantity(LBKUM), the moving average price must be adjusted accordingly, which ultimately requires an exclusive lock until the V1 update. The quantity/value ratio is mainly changed by goods movements with an external value (for example, from the purchase order). However, if the change originates due to rounding differences only, the moving average price is not adjusted anymore.
Exceptional locking during new Batch creation(split valuation),
Exclusive locking is still required, if material master data is created or changed by a goods movement. Material master data is created by a goods movement, if split valuation is used and a new batch has to be created for instance.
Late shared locks for plants that do not allow negative stocks,
With S/4HANA OP1610 and CE1608 a further option to increase throughput will be introduced. This is the option to define in the customizing that, for the late lock strategy, no exclusive lock shall be set. In this case only late shared locks will be set which really enables parallel material document processing (stock underrun checks are still possible because in this case all processes communicate their withdrawals to the lock server who in this case serves as second storage for stock changes (first storage is the DB) and the calculation operates on data from the first and the second storage).
Locks on batches only if batch master data is changed,
Starting with S/4HANA OP1610 and CE1608, to reduce the collision rate of parallel material document postings for batch material line items those batch locks will be set only if the batch master data like production date or best before date are entered during the MM-IM document processing and these data differ from the data on the DB.
Optimizations in On-the-fly calculations,
According to the on-the-fly calculation, read accesses to those hybrid and aggregate tables are much slower than in Suite on HANA where the aggregated quantity changes have been stored in these tables as actual stock quantity data.
To turn the drawback of on-the-fly calculation into an advantage the following will be introduced with S/4HANA OP1610 and CE1608:
- during the prefetch phase only the material master data will be read into internal buffers by using the pure material master data views to retrieve the data from DB
- during the item processing the stock quantity data will be read in the account model from the data base, and this will be done only in case of stock decreasing processes where negative stocks are prohibited.
Hence for S/4HANA OP1610 and CE1608, the adaptation done for the late lock strategy allows parallel execution of material document processes whereas the stock quantity read from DB and stock underrun check reduces the processing time of a single material document process. Overall it increases the performance of material document processing in S/4HANA OP1610 and CE1608 compared to S/4HANA OP1511 and Suite on HANA.
For plants that allow negative stocks,
- no locks at all will be set in the late lock strategy case.
- no stock determination from the data base will be done and no stock underrun check will be executed (in both lock strategies).
A very nice blog post!