Database Reference
In-Depth Information
Figure 6-9
The Streams Graphical Editor and SPL editor are linked for round-trip
updates.
also possible to quickly gather and display logs from the cluster if an application
is not behaving as expected. For example, Streams Studio applies coloriza-
tion to a job and its operators, and even colors the PE containing the operator,
so that different PEs have different colors.
Additionally, by clicking on any operator, it is possible to highlight up-
stream or downstream operators to understand provenance (the origin of the
data and any changes applied to it in the stream). The ability to quickly see
the upstream operators is extremely useful for debugging large applications
when an operator is not receiving the data that is expected. For example, if an
operator is not receiving data, by highlighting upstream operators you can
quickly trace back to the problem in the application. Figure 6-10 shows an
Instance Graph with both the VWAP and TrendCalculator job running. Opera-
tors that are upstream from the
QuoteWriter
operator are highlighted to
determine what generates its data.
One of the most useful new features in Streams Studio for debugging
applications is the ability to click on a stream in an Instance Graph to display
the data that is flowing on that stream. As in the Table view in the Streams
