2026-07-27T05:06:45Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:25638 2026-06-23T12:04:12Z ddc:004 open_access

Database Theory in Action: Evaluation of Aggregate Queries Without Materialisation Lanzinger, Matthias Pichler, Reinhard Selzer, Alexander Join Processing Aggregate Queries Acyclic Conjunctive Queries Aggregate queries often require computing large intermediate joins despite producing only small outputs. We identify broad classes of acyclic aggregate queries that can be evaluated without materialising any join results, using a bottom-up, semi-join–based propagation of cardinalities and partial aggregates. An implementation in Spark SQL shows that this approach is widely applicable and yields substantial performance gains on standard benchmarks. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Matthias Lanzinger and Reinhard Pichler and Alexander Selzer 2026 Is Part Of LIPIcs, Volume 365, 29th International Conference on Database Theory (ICDT 2026) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.ICDT.2026.24 urn:nbn:de:0030-drops-256380 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2026.24 eng https://creativecommons.org/licenses/by/4.0/legalcode