EDBT 2026 Demo / reviewers in the wild / expert
Fotis Psallidas
dblp:135/5141
· DBLP profile ↗
14ranked-venue papers in the field
5as first author
6since 2021 · last 2024
0000-0003-4110-5813ORCID · corroborated
Domains — venue-derived; a paper can count in several
Database Systems & Data Management · 12 (4 first)Data Mining & Knowledge Discovery · 1Information Retrieval & Web Search · 1 (1 first)
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2024 | NL2SQL is a solved problem... Not!
Avrilia Floratou, Fotis Psallidas, Fuheng Zhao, Shaleen Deep, Gunther Hagleither, Wangda Tan, Joyce Cahoon, Rana Alotaibi, Jordan Henkel, Abhik Singla, Alex Van Grootel, Brandon Chow, Katherine Lin, Marcos Campos, K. Venkatesh Emani, Vivek Pandit, Victor Shnayder, Wenjing Wang 0005, Carlo Curino |
CIDR | 2 |
| 2024 | Rapidash: Efficient Detection of Constraint ViolationsabstractDenial Constraint (DC) is a well-established formalism that captures a wide range of integrity constraints commonly encountered, including candidate keys, functional dependencies, and ordering constraints, among others. Given their significance, there has been considerable research interest in achieving fast detection of DC violations, especially to support activities related to data exploration and preparation. Despite the significant advancements in the field, prior work exhibits notable limitations when confronted with large-scale datasets: the current state-of-the-art algorithm demonstrates a quadratic (worst-case) time and space complexity relative to the dataset's number of rows. In this paper, we establish a connection between orthogonal range search and DC violation detection. We then introduce Rapidash, a novel algorithm that demonstrates near-linear time and space complexity, representing a theoretical improvement over prior work. To validate the effectiveness of our algorithm, we conduct comprehensive evaluations on both open-source and real-world production datasets, with our production datasets notably being an order of magnitude larger than the datasets employed in prior studies. Our results reveal that Rapidash achieves up to 84× faster performance compared to state-of-the-art approaches while also exhibiting superior scalability. Zifan Liu, Shaleen Deep, Anna Fariha, Fotis Psallidas, Ashish Tiwari 0001, Avrilia Floratou |
Proc. VLDB Endow. | 4 |
| 2024 | Sphinteract: Resolving Ambiguities in NL2SQL Through User InteractionabstractTranslating natural language questions into SQL queries (NL2SQL) is a challenging task of great practical importance. Prior work has extensively studied how to address NL2SQL using Large Language Models (LLMs) with solutions ranging from careful prompt engineering, to fine-tuning existing LLMs, or even training custom models. However, a remaining challenging problem in NL2SQL is the inherent ambiguity in the natural language questions asked by users. In this paper, we introduce Sphinteract, a framework designed to assist LLMs in generating high-quality SQL answers that accurately reflect the user intent. Our key insight to resolve ambiguity is to take into account minimal user feedback interactively. We introduce the Summarize, Review, Ask (SRA) paradigm, which guides LLMs in identifying ambiguities in NL2SQL tasks and generates targeted questions for the user to answer. We propose three different methods of how to process user feedback and generate SQL queries based on user input. Our experiments on the challenging KaggleDBQA and BIRD benchmarks demonstrate that by means of asking clarification questions to the user, LLMs can efficiently incorporate the feedback, resulting in accuracy improvements of up to 42%. Fuheng Zhao, Shaleen Deep, Fotis Psallidas, Avrilia Floratou, Divyakant Agrawal, Amr El Abbadi |
Proc. VLDB Endow. | 3 |
| 2023 | Schema Matching using Pre-Trained Language ModelsabstractSchema matching over relational data has been studied for more than two decades. However, the state-of-the-art methods do not address key modern-day challenges encountered in real customer scenarios, namely: 1) no access to the source (customer) data due to privacy constraints, 2) target schema with a much larger number of entities and attributes compared to the source schema, and 3) different but semantically equivalent entity and attribute names in the source and target schemata. In this paper, we address these shortcomings. Using real-world customer schemata, we demonstrate that existing linguistic matching approaches have low accuracy. Next, we propose the Learned Schema Mapper (LSM), a novel linguistic schema matching system that leverages the natural language understanding capabilities of pre-trained language models to improve the overall accuracy. Combining this with active learning and a smart attribute selection strategy that selects the most informative attributes for users to label, LSM can significantly reduce the overall human labeling cost. Experimental results demonstrate that users can correctly match their full schema while saving as much as 81% of the labeling cost compared to manual labeling. Avrilia Floratou, Joyce Cahoon, Subru Krishnan, Andreas Müller 0024, Dalitso Banda, Fotis Psallidas, Jignesh M. Patel |
ICDE | 7 |
| 2023 | Optimizing Data Pipelines for Machine Learning in Feature StoresabstractData pipelines (i.e., converting raw data to features) are critical for machine learning (ML) models, yet their development and management is time-consuming. Feature stores have recently emerged as a new "DBMS-for-ML" with the premise of enabling data scientists and engineers to define and manage their data pipelines. While current feature stores fulfill their promise from a functionality perspective, they are resource-hungry---with ample opportunities for implementing database-style optimizations to enhance their performance. In this paper, we propose a novel set of optimizations specifically targeted for point-in-time join, which is a critical operation in data pipelines. We implement these optimizations on top of Feathr: a widely-used feature store, and evaluate them on use cases from both the TPCx-AI benchmark and real-world online retail scenarios. Our thorough experimental analysis shows that our optimizations can accelerate data pipelines by up to 3× over state-of-the-art baselines. Rui Liu 0002, Kwanghyun Park 0001, Fotis Psallidas, Xiaoyong Zhu, Jinghui Mo, Rathijit Sen, Matteo Interlandi, Konstantinos Karanasos, Yuanyuan Tian 0001, Jesús Camacho-Rodríguez |
Proc. VLDB Endow. | 3 |
| 2023 | OneProvenance: Efficient Extraction of Dynamic Coarse-Grained Provenance From Database Query Event LogsabstractProvenance encodes information that connects datasets, their generation workflows, and associated metadata (e.g., who or when executed a query). As such, it is instrumental for a wide range of critical governance applications (e.g., observability and auditing). Unfortunately, in the context of database systems, extracting coarse-grained provenance is a long-standing problem due to the complexity and sheer volume of database workflows. Provenance extraction from query event logs has been recently proposed as favorable because, in principle, can result in meaningful provenance graphs for provenance applications. Current approaches, however, (a) add substantial overhead to the database and provenance extraction workflows and (b) extract provenance that is noisy, omits query execution dependencies, and is not rich enough for upstream applications. To address these problems, we introduce OneProvenance: an efficient provenance extraction system from query event logs. OneProvenance addresses the unique challenges of log-based extraction by (a) identifying query execution dependencies through efficient log analysis, (b) extracting provenance through novel event transformations that account for query dependencies, and (c) introducing effective filtering optimizations. Our thorough experimental analysis shows that OneProvenance can improve extraction by up to ~18X compared to state-of-the-art baselines; our optimizations reduce the extraction noise and optimize performance even further. OneProvenance is deployed at scale by Microsoft Purview and actively supports customer provenance extraction needs (https://bit.ly/3N2JVGF). Fotis Psallidas, Ashvin Agrawal, Chandru Sugunan, Khaled Ibrahim, Konstantinos Karanasos, Jesús Camacho-Rodríguez, Avrilia Floratou, Carlo Curino, Raghu Ramakrishnan 0001 |
Proc. VLDB Endow. | 1 |
| 2020 | Cloudy with high chance of DBMS: a 10-year prediction for Enterprise-Grade ML
Ashvin Agrawal, Rony Chatterjee, Carlo Curino, Avrilia Floratou, Neha Godwal, Matteo Interlandi, Alekh Jindal, Konstantinos Karanasos, Subru Krishnan, Brian Kroth, Jyoti Leeka, Kwanghyun Park 0001, Hiren Patel, Olga Poppe, Fotis Psallidas, Raghu Ramakrishnan 0001, Abhishek Roy 0008, Karla Saur, Rathijit Sen, Markus Weimer, Travis Wright |
CIDR | 15 |
| 2020 | Extending Relational Query Processing with ML Inference
Konstantinos Karanasos, Matteo Interlandi, Fotis Psallidas, Rathijit Sen, Kwanghyun Park 0001, Ivan Popivanov, Doris Xin, Supun Nakandala, Subru Krishnan, Markus Weimer, Raghu Ramakrishnan 0001, Carlo Curino |
CIDR | 3 |
| 2020 | Vamsa: Automated Provenance Tracking in Data Science ScriptsabstractThere has recently been a lot of ongoing research in the areas of fairness, bias and explainability of machine learning (ML) models due to the self-evident or regulatory requirements of various ML applications. We make the following observation: All of these approaches require a robust understanding of the relationship between ML models and the data used to train them. In this work, we introduce the ML provenance tracking problem: the fundamental idea is to automatically track which columns in a dataset have been used to derive the features/labels of an ML model. We discuss the challenges in capturing such information in the context of Python, the most common language used by data scientists. Mohammad Hossein Namaki, Avrilia Floratou, Fotis Psallidas, Subru Krishnan, Ashvin Agrawal, Yinghui Wu 0001, Markus Weimer |
KDD | 3 |
| 2018 | Demonstration of Smoke: A Deep Breath of Data-Intensive Lineage ApplicationsabstractData lineage is a fundamental type of information that describes the relationships between input and output data items in a workflow. As such, an immense amount of data-intensive applications with logic over the input-output relationships can be expressed declaratively in lineage terms. Unfortunately, many applications resort to hand-tuned implementations because either lineage systems are not fast enough to meet their requirements or due to no knowledge of the lineage capabilities. Recently, we introduced a set of implementation design principles and associated techniques to optimize lineage-enabled database engines and realized them in our prototype database engine, namely, Smoke. In this demonstration, we showcase lineage as the building block across a variety of data-intensive applications, including tooltips and details on demand; crossfilter; and data profiling. In addition, we show how Smoke outperforms alternative lineage systems to meet or improve on existing hand-tuned implementations of these applications. Fotis Psallidas, Eugene Wu 0002 |
SIGMOD Conference | 1 |
| 2018 | Smoke: Fine-grained Lineage at Interactive SpeedabstractData lineage describes the relationship between individual input and output data items of a workflow and is an integral ingredient for both traditional (e.g., debugging or auditing) and emergent (e.g., explanations or cleaning) applications. The core, long-standing problem that lineage systems need to address---and the main focus of this paper---is to quickly capture lineage across a workflow in order to speed up future queries over lineage. Current lineage systems, however, either incur high lineage capture overheads, high lineage query processing costs, or both. In response, developers resort to manual implementations of applications that, in principal, can be expressed and optimized in lineage terms. This paper describes S moke , an in-memory database engine that provides both fast lineage capture and lineage query processing. To do so, S moke tightly integrates the lineage capture logic into physical database operators; stores lineage in efficient lineage representations; and employs optimizations if future lineage queries are known up-front. Our experiments on microbenchmarks and realistic workloads show that S moke reduces the lineage capture overhead and lineage query costs by multiple orders of magnitude as compared to state-of-the-art alternatives. On real-world applications, we show that S moke meets the latency requirements of interactive visualizations (e.g., < 150ms) and outperforms hand-written implementations of data profiling primitives. Fotis Psallidas, Eugene Wu 0002 |
Proc. VLDB Endow. | 1 |
| 2017 | Combining Design and Performance in a Data Visualization Management System
Eugene Wu 0002, Fotis Psallidas, Zhengjie Miao, Haoci Zhang, Laura Rettig |
CIDR | 2 |
| 2015 | S4: Top-k Spreadsheet-Style Search for Query DiscoveryabstractAn enterprise information worker is often aware of a few example tuples that should be present in the output of the query. Query discovery systems have been developed to discover project-join queries that contain the given example tuples in their output. However, they require the output to exactly contain all the example tuples and do not perform any ranking. To address this limitation, we study the problem of efficiently discovering top-k project join queries which approximately contain the given example tuples in their output. We extend our algorithms to incrementally produce results as soon as the user finishes typing/modifying a cell. Our experiments on real-life and synthetic datasets show that our proposed solution is significantly more efficient compared with applying state-of-the-art algorithms. Fotis Psallidas, Bolin Ding, Kaushik Chakrabarti, Surajit Chaudhuri |
SIGMOD Conference | 1 |
| 2013 | Soc Web: Efficient Monitoring of Social Network Activities
Fotis Psallidas, Alexandros Ntoulas, Alex Delis |
WISE (2) | 1 |