Towards Planning of Regular Queries with Memory.

We investigate efficient evaluation of regular path queries with memory (RQM), which are an extension of regular path queries (RPQ) with additional constraints on data encountered along a path in a graph. We show how Waveguide, a state of the art system capable of planning RPQs, can be extended to facilitate RQM planning. Furthermore, we show that RQM planning is not as trivial as finding a conventional optimal join order and addingon data constraints. Rather, we showcase that efficient evaluation of RQMs poses a number of non-trivial novel challenges.