Between uri dereferencing and the sparql protocol lies a largely
unexplored axis of possible interfaces to Linked Data, eachwith its own combination of trade-offs. One of these interfaces is Triple Pattern Fragments, which allows clients to execute sparql queries against low-cost servers, at the cost of higher bandwidth. Increasing a client’s efficiency means lowering the number of requests, which can among others be achieved through additional metadata in responses.
We noted that typical sparql query evaluations against Triple Pattern Fragments
require a significant portion of membership subqueries, which check the presence
of a specific triple, rather than a variable pattern. This paper studies the impact
of providing approximate membership functions, i.e., Bloom filters and Golombcoded
sets, as extra metadata. In addition to reducing http requests, such functions
allow to achieve full result recall earlier when temporarily allowing lower precision.
Half of the tested queries from aWatDiv benchmark test set could be executed with
up to a third fewer http requests with only marginally higher server cost. Query
times, however, did not improve, likely due to slower metadata generation and
transfer. This indicates that approximate membership functions can partly improve
the client-side query process with minimal impact on the server and its interface.