SAP ATP Server

Overview

The SAP ATP (Available To Promise) server caches availability checks in the export/import buffer, replacing database calls to RESB and VBBE.

Reference:

SAP Note 99999 ATP server: Installation and sizing (https://service.sap.com/sap/support/notes/99999)

https://service.sap.com/sap/support/notes/702728"SAP Note 702728 Profile parameter for export/import buffer instances (https://service.sap.com/sap/support/notes/702728)

https://service.sap.com/sap/support/notes/373986"SAP Note 373986 Overflow of the export/import buffer (https://service.sap.com/sap/support/notes/373986)

SAP Performance Optimization Guide (6th Edition), Thomas Schneider, Galileo Press (2009), section 10.4, pp. 443-450. (http://www.sap-press.com/products/SAP-Performance-Optimization-Guide-%286th-Edition%29.html)

Install the ATP Server

Pick a suitable SAP Instance to run the ATP server, subject to the space constraints below.

The ATP server is a logical service activated by a profile parameter, and since all of the instances servers will use this same server, the parameter should be set in the DEFAULT profile (transaction RZ10). The ATP server and Enqueue server should run in the same instance.

Set both:

rdisp/enqname

rdisp/atp_server

Restart the instances to pick up the changes

Tune the Export/Import Buffer

Figure out how many objects you plan to cache. Either follow the elaborate formulas in the references above, or just flush the cache, run a sample test, and extrapolate. Quick and dirty guideline: figure out how many maximum objects youll ever need (rsdb/obj/max_objects) and set it, and set the Export/Import Buffer (size in KB) to twice that number (rsdb/obj/buffersize), since each object should take a little less than half a KB. Tune as needed.

Transactions

RZ10 Set parameters.

ST02 View buffer statistics.

SM50/SM51 Verify ATP and Enqueue servers activated.

ACDB View and delete export/import buffer table entries.

Some of the OSS notes which can be of use to you for ATP server are as follows.

133418

140524

150578

163819

180349

168889

168692

303189

335965

ATP-Server

An Available-To-Promise-Server provides all the data available throughout a company. When demand is increasing the system can define supply expectations and support their fulfillment.

As of Release 4.0A, the availability check can be carried out on a

dedicated application server, the ATP server. You can make the following

checks (basic methods):

o Check according to the ATP logic

o Check for planned independent requirements

o Check for allocations

The ATP server has a cross-transaction, global memory (shared

buffer),where ATP-relevant information, for example, requirement date,

requirement quantity and confirmed quantity of the database tables

RESB(Reservations/dependent requirements) and VBBE (Sales

Requirements:

Individual Records) is aggregated according to the date for one day at a

time. When you check material availability the system reads the data of

the two mentioned tables from the shared buffer instead of from The

database. This method of access considerably improves the performance. A

corresponding delta processing ensures data consistency between the

shared buffer and the database.

The ATP server is not a separate installation. As an application

servers, it is part of the used R/3 installation.

Installation and Sizing of the ATP server

Below we describe the necessary actions to install the ATP server

correctly. If you do not do this (standard system) then the check is

carried out without the use of the shared buffer, that is, the

system always reads the ATP-relevant data of database tables RESB and

VBBE from the database.

Changes to the system administration

Change the following SAP parameters:

o RFC address of the ATP server (parameter: rdisp/atp_server):

As

with the Enqueue server, you must enter the name of the application

server which is to be used as an ATP server (see Transaction SM51: SAP

server). This parameter must be displayed for all application servers, it

should be entered in the

default profile.

The following parameters are only important for the ATP

server, thus, you have to enter them into the instance profile of the ATP

server.

Size of the shared buffers (parameter:

rsdb/obj/buffersize):As a first approach you can estimate the size of the

shared buffer as follows: For each table (RESB and VBBE), client,

material, and plant, there is an object in the shared buffer. The size of

this object mainly depends on the number of the organizational

levels(storage locations, batches and MRP element indicators which are

stored in tables RESB and VBBE) and the number of the different

dates for each organizational level. For each organizational level

and date you need 25 byte.

Example for a VBBE object: 3 storage locations, no batch, 10 dates

For each storage location, 2 MRP elements: Sales orders and deliveries.

The result is (25 byte x. x 3 x 2 ) + (25 x 3 x 2) = 1650 byte

Storage requirement for this object. If 10000 combinations of material

and Plant should be buffered in the shared buffer, then 1650 byte x 10000

Are required. You must carry out a similar estimation for table RESB if

corresponding MRP items occur in the check according to scope of check.

In addition there is the administrative overhead for the shared buffer

and the object directory, which contains the objects. This factor largely

depends on the maximum number of stored objects (see below) and is in the

scale of 10%-20%.

o Max. number of stored objects (parameter:

rsdb/obj/max_objects):For this parameter you should choose a

value which is about twice as large as the number of ATP-relevant

client/material/plant combinations, if you want to carry out the

ATP check for both sales requirements and material reservations.

o Maximum size of a stored object (parameter:rsdb/obj/large_object_size) here the default value will generally be correct. In addition you may have to adjust some configuration parameters of the application server which is defined as an ATP server to handle the additional processing steps and the remote function calls efficiently: o Maximum number of logged on users (parameter: rdisp/tm_max_no): Specify how many users can log on at the same time to an application server.The default is 200, the value should be larger than the maximum number of users which want to carry out ATP checks simultaneously. o Maximum number RFC connections (parameter: gw/max_conn):Here, the default is 500, this will normally be enough. o Number of dialog work processes (rdisp/wp_no_dia):On the ATP server, increase the number of dialog work processes by 1 - 2 processes. For more information on these parameters see Transactions RZ11 and ST02. More information on the gateway you will find in Transaction SMGW (gateway monitor). In particular, after you setup the ATP server with Transaction ST02, you should check the buffer update settings. Actions to correct errors in the dataset For the shared buffer of the ATP server Transaction ACBD offers Other monitoring and administration functions, for example: o complete or partial deletion of the shared buffer(concerning ATP data) o comparison of the shared buffer with the database This transaction permits you to load the data from the database into the shared buffer in advance. Otherwise, the data is loaded for each client, material, plant, and table at the date of the first availability check for this combination. Additional key words ATP, performance Cause and prerequisites Important preconditions which should be taken into account during The installation of the ATP server: o During the installation all application servers must be stopped so the default parameters are transferred. o The check with quantity block (see Customizig availability check SD [Tabelle TMVF]) must be active. o To keep the data transfer low the ATP server should be selected like the enqueue server. o Make sure you applied the related notes into your system.

SM12 - Maximum records in lock table and enque/table size

SM12 -> Extras -> Statistics shows the Lock Entries Table Size = 3603. One of the SAP programs (RPCIPE00) is causing a Lock table overflow (locking 3602 recrods). I had increased the profile parameter "enque/table_size" from the default of 4096 to 10000. After bouncing the system, SM12 still shows a Lock Entries table Size of 3603. I checked my production system which also shows a table size of 3603, yet the "enque/table_size" over there is set to 40960. I guess I am realizing that this parameter has no affect on the maximum number of records that can be locked. What does affect this value in SM12?

Ans: I discovered my problem. I was altering the profile parameter in my DVEBMGS instance, but we run the enqueue server on our z/OS mainframe under USS. It is that profile that the enqueue server reads to set the lock table size. I guess RZ10 & RZ11 do not look at the profiles for the enqueue server when run "elsewhere".

ATP Server and Buffer Updation

What is ATP Server ?

Companies which are operating with large volume of data usually faces long time to perform availability check. Databases associated with availability check are RESB and VBBEThe ATP server has a cross-transaction, global memory (shared buffer),where ATP-relevant information like RESB/VBBE are aggregated according to the date for one day time.When we check material availability the system reads the data of the two mentioned tables from the shared buffer instead of from he database. This method of access considerably improves the performance. Transaction ACBD and Its Usage:Transaction ACBD offers further monitoring and administrative functions for t Shared Buffer of the ATP Server:

Complete or partial deletion of the Shared Buffer

Comparison of the Shared Buffer with the database

This transaction also allows you to preload the data from the database into the Shared Buffer. (This is required for after every MRP run)

If we not loaded, the data is loaded the first time availability is checked - which could take some time.

Make ATP Job after the MRP Job Periodically:

Generally ACBD transaction is executed at Plant level which will run long time depends upon the volume of the data.

We can create several selection screen variant based business criteria.

Scheduling this ATP run with this selection screen variants after each MRP run is tedious one.

For this we can use background job after event method to run periodically.

Step 1: Create event in SM62