Cost-Based Optimization of Integration Flows - Datenbanken ...

2 Preliminaries and Existing Techniques
Receive (o1)
[service: s3, out: msg1]
Assign (o1)
[out: msg1]
@type='MATMAS04'
Translation (o3)
[in: msg1, out: msg2]
Assign (o4)
[in: msg2, out: msg3]
Switch (o2)
[in: msg1]
Invoke (o7)
[service s1, in: msg3]
@type='MATMAS05'
Translation (o5)
[in: msg1, out: msg2]
Assign (o6)
[in: msg2, out: msg3]
Receive (o1)
[service: s5, out: msg1]
Assign (o2)
[in: msg1, out: msg2]
Invoke (o3)
[service: s4, in: msg2, out: msg3]
INNER
Join (o4)
[in: msg1,msg3, out: msg4]
Invoke (o2)
[service s1, in: msg1, out msg2]
Invoke (o3)
[service s2, in: msg1, out msg3]
Join (o4)
[in: msg2,msg3, out: msg4]
Groupby (o5)
[in: msg4, out: msg5]
INNER
Assign (o8)
[in: msg2, out: msg4]
Assign (o5)
[in: msg4, out: msg5]
Assign (o6)
[in: msg5, out: msg1]
Invoke (o9)
[service s2, in: msg4]
Invoke (o6)
[service s3, in: msg5]
Invoke (o7)
[service s3, in: msg1]
(a) Plan P 1
(b) Plan P 2
(c) Plan P 3
Figure 2.9: Example Horizontal Integration Flows
2.4.1 Horizontal Integration: EAI
The use case of horizontal integration addresses the integration of the operational systems
(SCM, Material, ERP, CRM, and eCommerce) of our example scenario. This use case
is typical for EAI (Enterprise Application Integration) scenarios, where updates within
an operational system trigger immediate data synchronization in the sense of message
exchange by data-driven integration flows. Due to the OLTP character in terms of many
short business transactions in the operational systems, many instances of integration flows
with rather small amounts of data per instance are executed over time. Within the scope
of this use case, various integration flows exist. We pick four concrete examples with
different characteristics and define these integration flows in detail.
Example 2.4 (Material Synchronization). Figure 2.9(a) illustrates an integration flow
(plan P 1 ) that is used to synchronize material (basic material and products) master data
from the ERP system to the SCM system as well as to the Material system. Essentially,
when new material has been created within the ERP system, a proprietary material message
is automatically sent to the integration platform. This asynchronously initiates a plan
instance of P 1 . The Receive operator (o 1 ) writes the internal message to an instancelocal
variable. Subsequently, a Switch operator o 2 evaluates the message type (MATMAS04
or MATMAS05 for inter-version compatibility) and decides which alternative Switch path is
executed. After specific schema transformations (Translation) that differ according to
the present message type, queries are prepared (Assign) in order to send (Invoke) the
data to the external systems s 1 (SCM) and s 2 (Material).
Example 2.5 (Orders Processing). The integration flow (plan P 2 ) shown in Figure 2.9(b)
propagates order messages that have been submitted within our eCommerce Web shop to
the central ERP system. During execution of an instance of this plan, additional master
data of the customer are read from the CRM database and joined to this message. In
detail, the Receive operator (o 1 ) gets an orders message from the queue and writes it
to a local variable. Then, the Assign operator (o 2 ) is used in order to prepare a query
with the customer name of the received message as a parameter. Subsequently, the Invoke
operator (o 3 ) queries the external system s 4 (CRM system) in order to load master data
information for that customer. Here, one SQL query Q i per plan instance (per received
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