SAP Note 23278 - MD01, MDBT: Performance during MRP run

Symptom:

The runtime of materials planning (total planning or single-item planning) is unsatisfactory.

Other terms

Material requirements planning (MRP), RMMRP000, RMMRP010, RMMPS000, MD01, MD02, MD40, MS01, MS02,
MDBT, MDBS, MSBT, AUSP

Reason and Prerequisites

The performance depends on a large number of factors:
A. Organizational:
A1) Type of the planning run: Net change or regenerative planning (intensive)
A2) Planning mode: Reactivate or reset planning dates (intensive)
A3) Lead time scheduling: no or yes (intensive)
A4) Planning horizon
A5) Create MRP lists: only for exceptions or always (intensive)
A6) If the Purchasing Information System is active, the performance
depends on whether the key figures are updated in a
monthly, weekly or daily period split (intensive).
A7) Parallel processing (improves the runtime significantly)

B. Technical
B1) Response times of the hard disks
B2) Database
B3) Buffering SAP number ranges
B4) Program errors or unfavorable database accesses during lead time
scheduling via the routing
B5) Performance of the hardware
B7-B9) Implementation of notes for specific performance problems

Solution
The runtime can generally be reduced significantly by technical and organizational measures. See Note
204517.

Basically, take into account (sorted according to importance):
B2, A1, A2, A7, B5, B1, A6, A5
During lead time scheduling:
B4, A3
When configuring:
B8
Long selection times for planning file entries at many plants (>100)
B9

A. Organizational
------------------
A1) Only use regenerative planning (NEUPL) in exceptional cases.
A2) Only work with planning mode 3
"Reset planning dates" in exceptional cases (see Note 135788).
A3) Scheduling via the routing is time and work intensive.
The total runtime is strongly determined by how it is used.

- Scheduling using the routing should be limited to the
time horizon in which it is required.
(Customizing: Production -> Material Requirements Planning -> Planning ->
Scheduling and Capacity Parameters -> Define scheduling parameters for planned orders)

- Scheduling using the routing should be limited to the
scheduling levels on which it is needed.
Recommendation: Only schedule on one scheduling level, except
when capacities must be planned on several levels.

(Customizing: Production -> Material Requirements Planning -> Planning ->
Scheduling and Capacity Parameters -> Define scheduling parameters for planned orders)

- Very important: Implement the notes listed under B4)
A4) In critical cases, performance can be improved by restricting the planning horizon.

(Customizing: Production -> Material Requirements Planning -> Planning ->
MRP Calculation -> Define Planning Horizon)
In this case, the planning run must be started using transaction
NETPL. Planning must also be carried out regularly in the
entire horizon (NETCH) (for example, weekly or monthly).

A5) We recommend that you only create MRP lists for those materials
that generate exception messages in normal operation.

A6) If a large number of delivery schedules are created by materials planning,
and the Purchasing Information System is active, the key figures should be updated
if possible in the monthly or weekly split.
A7) We generally recommend using parallel processing in MRP.
This improves performance significantly.


Furthermore, important organizational measures (amongst others, the reduction of the number of entries in the table RESB) are described in Note 204517.

B. Technical
------------
B1) The system administrator should check the response times of the hard disks.
Incorrectly configured hard disks can result in serious performance problems.

B2) Database (IMPORTANT):
- The statistics for the indexes must be updated regularly (weekly) (update statistics)..
Note: The statistics update takes place automatically for the Microsoft SQL Server.


- For some databases, in particular for a large number of
stock transport orders:
Note 112765 (not relevant for Oracle)
Note 440651 (in particular ORACLE)
- Database administrator checks the database parameters
B3) Buffer number ranges for number range objects:
RESB: Buffer 100 entries
This improves performance slightly.
B4) Implement or take the following notes for scheduling via the
routing into account. This improves performance considerably
(in some cases more than 80 %).
Notes: 63395 (3.0D - 3.0F)
70099 (3.0D)
181271 (3.0D-4.6B)
B5) If all other measures have been exhausted, you must check whether the hardware is sufficient.

B6) Read the following notes when using release strategies with classification for
purchase requisitions that are created during the planning run:
Notes 46271 (3.0D), 86315(3.0E-3.0F) and 49585(3.0*).
B7) Implement the following notes when using configurable BOMs or routings:
Notes 68061 (3.0D-3.1H) and 72885 (3.0D-3.1G).

B7) Read the following notes when there are performance problems in the variant configuration area:
Notes 126810 (3.1H-4.0B), 162100 (3.0F-4.5B),
171919 (4.5A-4.5B), 184171 (3.0F-4.6B), 304364 (4.5B-4.6C),
311483 (4.5B-4.6C) and 211396 (4.0B-4.6C).
B9) For many plants (>100), you can improve performance by implementing
Note 78115 (3.0A-4.0B).

You can also avail of an EarlyWatch session to detect possible causes for performance problems with the emphasis on the MRP run (see Note 382037).