The Profiling perspective of the studio allows you to define multiple contexts for profiling analyses and select specific context values with which to execute an analysis. You can define context parameters in the analysis editor to:
filter data using contexts variables with WHERE clauses and decide the data or tables/columns on which to run the analysis,
decide the number of concurrent connections allowed by the analysis.
You usually set this number according to the database available resources, that is the number of concurrent connections each database can support.
You can use context variables only when you profile databases. Context variables can not be used when profiling files.