As per the definition of pivoting in the Solr wiki, it is a summarization tool that lets you automatically sort, count, total, or average data stored in a table. Pivot faceting lets you create a summary table of the results from a query across numerous documents.

The output of pivot faceting can be referred to as decision trees. This means the output of pivot faceting is represented by a hierarchy of all sub-facets under a facet with counts both for individual facets and sub-facets. We can constrain the previous facet with a new sub-facet and get counts of the sub-sub-facets inside it. Let us see an example to understand pivot faceting.

Facet A has constraints as X,Y with counts M for X and N for Y. We could go ahead and constrain facet A by X and get a new sub-facet B with constraints W,Z and counts O for W and P for Z.

To understand better how pivot faceting works and hence how it could be helpful in analytics, let us see an example. Our index contains some...