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MD01, MDBT: Performance during MRP run |
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Yazar Administrator
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Salı, 18 Aralık 2007 |
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 performance figures are updated in a
monthly, weekly or daily period split (intensive).
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
B6) Performance of the hardware
B7-B14) Implementing notes for special performance problems
A. Organizational
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A1) Only use regenerative planning (NEUPL) in exceptional cases.
A2) Only work with planning mode '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 via the routing should be limited to the time
horizon in which it is needed.
(Customizing Materials planning -> Operations -> Planning ->
In-house production -> Scheduling and capacity parameters ->
Define scheduling levels and capacity parameters).
- Scheduling via the routing should only be carried out for 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 Materials planning -> Operations -> Planning ->
In-house production -> Scheduling and capacity parameters ->
Define scheduling levels and capacity parameters).
- Very important: Implement the notes listed under B4)
A4) In critical cases, performance can be improved by restricting the
planning horizon.
(Customizing for materials planning -> Planning run -> Define
planning horizon -> Planning run).
In this case, the planning run must be started with transaction
code 'NETPL'. Planning must also be carried out regularly in the
entire release period (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
performance figures should be updated if possible in the monthly
or weekly split.
In addition, important organizational measures (among other the reduction of the number of entries in Table RESB) are described in Note 204517.
B. Technical
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B1) The system administrator should check the response times of the
hard disks. Incorrectly configured hard disks can cause
considerable losses in performance.
B2) Database:
- IMPORTANT for all databases:
(1) DOES NOT APPLY TO ADABAS!!!!!!
(1) The database indexes (primary and secondary indices) should
regularly be restructured for the following tables:
RESB, PLAF, EBAN, MDTB, MDKP, KBED
You can do this in R/3 with Transaction SE11 -> Database
utility -> Indexes -> 'Delete/Create again' or using the
database tool 'sapdba'.
You should also check the number of Extents, especially for
tables MDTB and RESB, and their indexes. If too many Extents
(> 20) exist, you should increase the size of the 'next
extent' and reorganize the table or the index.
This generally brings a considerable performance improvement.
(2) The index '1' for table RESB should be deleted.
(Transaction SE11, 'Indexes', ... 'Delete') since it is
contained in index 'M'.
- For some databases, in particular for a large
number of stock transport orders:
Note 112765 (not relevant for Oracle)
Note 440651 (in particular ORACLE)
B3) Buffer number ranges for number range objects:
RESB: Buffer 100 entries
This produces a small performance improvement.
B4) Implement or take the following notes for scheduling via the
routing into account. This leads to a large-scale improvement in
performance (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 tried unsuccessfully, you must
check whether the hardware is sufficient.
B6) When using release strategies with classification for purchase
requisitions which are created during the planning run:
Refer to Notes 46271 (3.0D), 86315 (3.0E-3.0F) and 49585 (3.0*).
B7) When using configurable BOMs or routings, implement Notes
68061 (3.0D-3.0F) and 72885 (3.0D-3.1G).
B8) 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) should be considered for performance problems in the area of variant configuration.
B9) For many plants (>100) you can improve performance by implementing
Note 78115 (3.0A-4.0B). |
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Son Güncelleme ( Salı, 18 Aralık 2007 )
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