SemBench: A Benchmark for Semantic Query Processing Engines

Jiale Lao
Gerardo Vitagliano
Immanuel Trummer
H. V. Jagadish
Sebastian Schelter
Andreas Kipf
Matthew Russo
Kris Kissel
Michael Cochez
Andreas Zimmerer
Olga Ovcharenko
Thibaud Hottelier
Gautam Gupta
Tianji Cong
2026

Abstract

We present a benchmark targeting a novel class of systems: semantic query processing engines. Those systems rely inherently on zero-shot abilities of state-of-the-art large language models (LLMs). They extend SQL with semantic operators, configured by natural language instructions, that are evaluated via LLMs and enable users to perform various operations on multimodal data. Our benchmark provides variety along three axis: scenarios, modalities, and operators. Included are scenarios ranging from movie review analysis to medical question-answering. Within these scenarios, we cover different data modalities, including images, audio, and text. Finally, the queries involve a diverse set of operators, including semantic filters, joins, mappings, ranking, and classification operators.

We evaluate systems according to processing overheads and result quality. We present experimental results for an industrial semantic query processing engine (BigQuery), as well as academic systems (LOTUS, Palimpzest, and ThalamusDB). Our results shed light on the relative strengths and weaknesses of the evaluated systems, and hint at promising avenues for future research.
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