1 code implementation • 28 Jan 2021 • Nikolaos Tziavelis, Wolfgang Gatterbauer, Mirek Riedewald
Our approach achieves strong time and space complexity properties: with $n$ denoting the number of tuples in the database, we guarantee for acyclic full join queries with inequality conditions that for every value of $k$, the $k$ top-ranked answers are returned in $\mathcal{O}(n \operatorname{polylog} n + k \log k)$ time.
Databases Data Structures and Algorithms
no code implementations • 22 Dec 2020 • Nofar Carmeli, Nikolaos Tziavelis, Wolfgang Gatterbauer, Benny Kimelfeld, Mirek Riedewald
For each of the two problems, we give a decidable characterization (under conventional complexity assumptions) of the class of tractable lexicographic orders for every CQ without self-joins.
Databases Data Structures and Algorithms
1 code implementation • 16 Feb 2018 • Xiaofeng Yang, Deepak Ajwani, Wolfgang Gatterbauer, Patrick K. Nicholson, Mirek Riedewald, Alessandra Sala
We therefore propose the novel notion of an any-k ranking algorithm: for a given time budget, re- turn as many of the top-ranked results as possible.
Social and Information Networks Databases Data Structures and Algorithms
