kind of retrospective provenance.
BizProv is a loosely-coupled architecture designed
to collect the retrospective business provenance
generated by distributed business processes. It allows
business analysts to incorporate other sources of data,
such as Web logs and clickstream to get deeper
visibility about business processes. BizProv was
conceived as a two layered architecture. The first
layer consists of a composite Web services provider,
basic Web services provider, E-Probe Module, two
active intermediaries, a provenance repository which
was conceived take into account the latest
recommendation of Open Provenance Model (Moreau
et al., 2011). The second layer is composed by a web
server log parser, an ETL tool and the OLAP
provenance data cubes. More details about BizProv
architecture and its provenance schema can be found
at Cruz et al. (2012).
3 OLAP PROVENANCE CUBES
Business provenance is inherently multidimensional;
it can be analyzed from multiple perspectives. The
BizProv´s OLAP Provenance Cubes are structures to
support analytical provenance queries in high-
dimensional space. The design of Provenance Cubes
requires addressing a variety of issues including a
novel set of OLAP dimensions, measures and also
defining the semantics of OLAP operations over
provenance cube. Last but not least, OLAP is a
technology widely used by enterprises and can be
distributed to business analysts using a variety of
platforms. For such reasons, despite of the existence
of other initiatives to query provenance metadata,
such as (Curbera et al., 2009, Lakshmanan et al., 2011
and Cruz et al., 2009). Our approach uses the
analytical processing to query business provenance
metadata.
This section shows how business analysts can gain
insight into business provenance metadata through
fast, consistent, interactive access to a wide variety of
possible views of information. One of the uses of
Web services´ provenance is to track QoS aspects of
Web services utilization. Such tracking provides
important feedback to service management.
3.1 A Business Use Case
From business provenance repositories generated by
BizProv and other sources of data (such as
clickstream and Web server logs) an ETL tool may
process and populate a database specially designed for
analytical purposes. Provenance metadata used in this
section was gathered from some Web services of a
virtual books retailer operating on the Web
Such database is usually structured according to a
star schema (it is a logical arrangement of tables such
as the entity relationship diagram without
normalization of tables (Kimball et al., 2004)), where
data are described in terms of facts, (measures of
interest to be analyzed) and dimensions (perspectives
under which the facts are analyzed). Thus, a
provenance OLAP cube is a set of metadata, with
distinct granularity, that is organized and structured in
a hierarchical and multidimensional arrangement to
allow analysts to perform ad hoc queries over
provenance repositories. The next sub-sections
provide two general star schemas based of the
provenance collected by BizProv architecture. The
first schema (Figure 1, at the end of the paper) may be
extended according to other needs, including
additional information such as service reputation
(used to obtain basic insights about the user
experience dealing with the Web services). The
second schema (Figure 2, at the end of the paper)
aims at capturing users’ interactions to support and to
complement business processes analyses.
3.2 Monitoring Web Services QoS
The schema, depicted in Figure 1, can be used to
investigate several QoS issues about the business
processes, such as ResponseTime, MessageSize and
InitializationTime. In order to investigate QoS,
different dimensions may be used to provide
consolidated queries upon these variables. For
instance, the Status dimension supports queries
concerning reliability and availability. For example,
selecting the total amount of services requisitions in
Dec 2011, by Web service method which ended with
a Status different from “OK”, divided by the total
amount of services requisitions (by Web service
method) in Dec 2011, gives us a Web service method
reliability indicator. This information may be used as
a basis for Web services code maintenance. Note that
we have included a service requisition attribute in the
fact table, just for convenience, for the sake of queries
readability, as suggested by Kimball et al. (2000,
2004). Its value is always 1.
The Origin dimension supports queries
concerning service misuse. For example, if the total
amount of a Web service requisition from a given
origin in an hour is much larger than the others, it
may be someone, by mistake or not, repeatedly
calling the service in a loop. This information may be
used for user suspension or warning. The Date and
Time dimensions are role playing dimensions
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