Sessionize with Style? …Or How a column-only, SQL-only database and lack of MapReduce, will cramp your style!
It’s ironic how all of a sudden Vertica is changing its focus from being a column-only database to claiming to be an Analytic Platform.
If you’ve used an Analytic Platform you know it’s more than just bolting in a layer of analytic functions on top of a database. But that’s how Vertica claims it’s now a full-blown analytic platform when in fact their analytics capability is rather thin. For instance, their first layer is a pair of window functions (CTE and CCE). The CCE window function is used, for example, to do sessionization. Vertica has a blog post that posits sessionization as a major advanced analytic operation. In truth, Vertica’s sessionization is not analytics. It is a basic data preparation step that adds a session attribute to each clickstream event so that very simple session-level analytics can be performed.
What’s interesting is the CCE window function is simply a pre-built function – some might say just syntactic sugar – that combines the functionality of finite width SQL window functions (LEAD/LAG) with CASE statements (WHEN condition THEN predicate). Nothing ground breaking to say the least!
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