Yuhao Deng

Yuhui Wang, Jinqi Liu, Chengliang Chai et al.

The diverse formats of CSV and Parquet files in data lakes pose a significant challenge to traditional ETL, which relies on data engineers to pre-define a target database schema and build a complex pipeline for data integration. Moreover, with this approach, the integrated data often cannot support various analytical needs, as the predefined schema does not necessarily satisfy the table format or join relationships required to answer unforeseen queries. To address this, we propose EcoTable, the first natural language-based data integration framework. Given a set of user-specified natural language queries, EcoTable automatically integrates the tables into a form that adequately supports the corresponding SQL queries. EcoTable achieves this by leveraging the semantic understanding and complex reasoning capabilities of LLMs. Moreover, EcoTable addresses the scalability and cost issues introduced by expensive LLM inferences with a set of novel ideas. First, EcoTable introduces a graph to represent the overall search space, where nodes represent tables and edges carry weights indicating join likelihood produced by a lightweight deep learning model. On top of this graph data structure, EcoTable designs three components to achieve our goal: (1) the table identification layer aims to identify relevant tables via a two-stage schema linking based on user queries; (2) the graph-based validation layer aims to discover significant join paths, including necessary data transformations and bridging tables, by modeling the problem as Steiner tree searches; and (3) the table transformation layer generates transformation code to implement the joins using LLMs. We construct 4 real-world benchmark datasets with more than 200 queries. Extensive experiments demonstrate that EcoTable outperforms the state-of-the-art baselines, increasing accuracy by more than 30% and cutting LLM invocation costs by 5 times.

Chi Zhang, Huaping Zhong, Hongtao Li et al.

Instruction tuning improves the performance of large language models (LLMs), but it heavily relies on high-quality training data. Recently, LLMs have been used to synthesize instruction data using seed question-answer (QA) pairs. However, these synthesized instructions often lack diversity and tend to be similar to the input seeds, limiting their applicability in real-world scenarios. To address this, we propose extracting instruction tuning data from web corpora that contain rich and diverse knowledge. A naive solution is to retrieve domain-specific documents and extract all QA pairs from them, but this faces two key challenges: (1) extracting all QA pairs using LLMs is prohibitively expensive, and (2) many extracted QA pairs may be irrelevant to the downstream tasks, potentially degrading model performance. To tackle these issues, we introduce EQUAL, an effective and scalable data extraction framework that iteratively alternates between document selection and high-quality QA pair extraction to enhance instruction tuning. EQUAL first clusters the document corpus based on embeddings derived from contrastive learning, then uses a multi-armed bandit strategy to efficiently identify clusters that are likely to contain valuable QA pairs. This iterative approach significantly reduces computational cost while boosting model performance. Experiments on AutoMathText and StackOverflow across four downstream tasks show that EQUAL reduces computational costs by 5-10x and improves accuracy by 2.5 percent on LLaMA-3.1-8B and Mistral-7B