Something’s Fishy in the Data Lake: A Critical Re-evaluation of Table Union Search Benchmarks

Allaa Boutaleb, Bernd Amann, Hubert Naacke, Rafael Angarita


Abstract
Recent table representation learning and data discovery methods tackle table union search (TUS) within data lakes, which involves identifying tables that can be unioned with a given query table to enrich its content. These methods are commonly evaluated using benchmarks that aim to assess semantic understanding in real-world TUS tasks. However, our analysis of prominent TUS benchmarks reveals several limitations that allow simple baselines to perform surprisingly well, often outperforming more sophisticated approaches. This suggests that current benchmark scores are heavily influenced by dataset-specific characteristics and fail to effectively isolate the gains from semantic understanding. To address this, we propose essential criteria for future benchmarks to enable a more realistic and reliable evaluation of progress in semantic table union search.
Anthology ID:
2025.trl-workshop.7
Volume:
Proceedings of the 4th Table Representation Learning Workshop
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Shuaichen Chang, Madelon Hulsebos, Qian Liu, Wenhu Chen, Huan Sun
Venues:
TRL | WS
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Publisher:
Association for Computational Linguistics
Note:
Pages:
71–85
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URL:
https://preview.aclanthology.org/acl25-workshop-ingestion/2025.trl-workshop.7/
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Cite (ACL):
Allaa Boutaleb, Bernd Amann, Hubert Naacke, and Rafael Angarita. 2025. Something’s Fishy in the Data Lake: A Critical Re-evaluation of Table Union Search Benchmarks. In Proceedings of the 4th Table Representation Learning Workshop, pages 71–85, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Something’s Fishy in the Data Lake: A Critical Re-evaluation of Table Union Search Benchmarks (Boutaleb et al., TRL 2025)
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https://preview.aclanthology.org/acl25-workshop-ingestion/2025.trl-workshop.7.pdf