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

2 Preliminaries and Existing Techniques
Message Broker [IBM10], MS Biztalk Server [Mic10], or Oracle SOA Suite [Ora10]. We
generalize this widely-accepted 1 common architecture to a reference architecture for integration
flows in order to survey existing work with regard to modeling, executing, and
optimizing integration flows. Furthermore, this system architecture—which is illustrated
in Figure 2.2—represents the foundation of this thesis from a system architecture perspective.
In detail, two major components are relevant: (1) a modeling component for
integration flow specification and (2) a runtime execution component that executes deployed
integration flows.
Modeling [Subsection 2.1.3]
Flow
Designer
Flow
External
System
External
System
External
System
Inbound
Adapter 1
...
Inbound
Adapter n
sync
async
Plan
Process Engine
Scheduler
Outbound
Adapter 1
...
...
Outbound
Adapter k
External
System
External
System
External
System
External
System
Temporary Datastore
Execution [Subsection 2.1.4]
Figure 2.2: Reference System Architecture for Integration Flows
The modeling component is used for specifying complex integration tasks by integration
flows in the form of graphs or hierarchies of operators and edges. Typically, the
configuration and administration of the execution environment is done via this modeling
component as well. From a research perspective, we concentrate only on the specification
of integration flows and discuss a classification as well as related approaches and languages
in Subsection 2.1.3.
The execution component consists of a set of inbound adapters, multiple message queues,
an internal scheduler (for time-based integration flows), a central process execution engine,
a set of outbound adapters, and a temporary data store (persistence of messages and
configuration meta data). The inbound adapters listen for incoming messages, transform
them into a common format (e.g., XML), and either append the messages to inbound
queues (in case of asynchronous flow execution) or directly forward them to the process
engine (in case of synchronous flow execution). Typically, those inbound adapters are
realized as decoupled listener threads (e.g., a TCP Listener) or standard APIs (e.g., an
HTTP implementation). Existing integration platforms provide many different technical
and application-level adapters for domain-specific data exchange standards such as HL/7
(Health Level 7) [hl707] or DICOM (Digital Imaging and Communications in Medicine)
[dic09] and proprietary system APIs (e.g., SAP R/3). Within the process engine, compiled
plans of deployed integration flows are executed. For this purpose, this engine includes
a flow parser for the deployment of integration flows and a runtime environment for the
1 There are plenty of existing application integration platforms. For a detailed survey of the major
products, we refer the interested reader to a related study conducted by the market research organization
Gartner [TSN + 08] and to a survey on SQL support in workflow products [VSRM08].
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