arXiv subjects

Jayant Haritsa

Publications and source records attributed to Jayant Haritsa.

4 recordsLinked to original sources

arXiv2025

Xpose: Bi-directional Engineering for Hidden Query Extraction

Query reverse engineering (QRE) aims to synthesize a SQL query to connect a given database and result instance. A recent variation of QRE is where an additional input, an opaque executable containing a ground-truth query, is provided, and the goal is to non-invasively extract this specific query through only input-output examples. This variant, called Hidden Query Extraction (HQE), has a spectrum of industrial use-cases including query recovery, database security, and vendor migration. The reverse engineering (RE) tools developed for HQE, which are based on database mutation and generation techniques, can only extract flat queries with key-based equi joins and conjunctive arithmetic filter predicates, making them limited wrt both query structure and query operators. In this paper, we present Xpose, a HQE solution that elevates the extraction scope to realistic complex queries, such as those found in the TPCH benchmark. A two-pronged approach is taken: (1) The existing RE scope is substantially extended to incorporate union connectors, algebraic filter predicates, and disjunctions for both values and predicates. (2) The predictive power of LLMs is leveraged to convert business descriptions of the opaque application into extraction guidance, representing ``forward engineering" (FE). The FE module recognizes common constructs, such as nesting of sub-queries, outer joins, and scalar functions. In essence, FE establishes the broad query contours, while RE fleshes out the fine-grained details. We have evaluated Xpose on (a) E-TPCH, a query suite comprising the complete TPCH benchmark extended with queries featuring unions, diverse join types, and sub-queries; and (b) the real-world STACK benchmark. The experimental results demonstrate that its bi-directional engineering approach accurately extracts these complex queries, representing a significant step forward with regard to HQE coverage.

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arXiv2025

Query Rewriting via LLMs

When complex SQL queries suffer slow executions despite query optimization, DBAs typically invoke automated query rewriting tools to recommend ``lean'' equivalents that are conducive to faster execution. The rewritings are usually achieved via transformation rules, but these rules are limited in scope and difficult to update in a production system. Recently, LLM-based techniques have also been suggested, but they are prone to semantic and syntactic errors. We investigate here how the remarkable cognitive capabilities of LLMs can be leveraged for performant query rewriting while incorporating safeguards and optimizations to ensure correctness and efficiency. Our study shows that these goals can be progressively achieved through incorporation of (a) an ensemble suite of basic prompts, (b) database-sensitive prompts via redundancy removal and selectivity-based rewriting rules, and (c) LLM token probability-guided rewrite paths. Further, a suite of logic-based and statistical tools can be used to check for semantic violations in the rewrites prior to DBA consideration. We have implemented the above LLM-infused techniques in the LITHE system, and evaluated complex analytic queries from standard benchmarks on contemporary database platforms. The results show significant performance improvements for slow queries, over both SOTA rewriters and the native optimizer. For instance, with TPC-DS on PostgreSQL, the GM of runtime speedups was a high 13.2 over the native optimizer, whereas SOTA only gave 4.9. Overall, LITHE is a promising step toward viable LLM-based advisory tools for ameliorating enterprise query performance.

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arXiv2003

On Addressing Efficiency Concerns in Privacy Preserving Data Mining

Data mining services require accurate input data for their results to be meaningful, but privacy concerns may influence users to provide spurious information. To encourage users to provide correct inputs, we recently proposed a data distortion scheme for association rule mining that simultaneously provides both privacy to the user and accuracy in the mining results. However, mining the distorted database can be orders of magnitude more time-consuming as compared to mining the original database. In this paper, we address this issue and demonstrate that by (a) generalizing the distortion process to perform symbol-specific distortion, (b) appropriately choosing the distortion parameters, and (c) applying a variety of optimizations in the reconstruction process, runtime efficiencies that are well within an order of magnitude of undistorted mining can be achieved.

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arXiv2001

The Building of BODHI, a Bio-diversity Database System

We have recently built a database system called BODHI, intended to store plant bio-diversity information. It is based on an object-oriented modeling approach and is developed completely around public-domain software. The unique feature of BODHI is that it seamlessly integrates diverse types of data, including taxonomic characteristics, spatial distributions, and genetic sequences, thereby spanning the entire range from molecular to organism-level information. A variety of sophisticated indexing strategies are incorporated to efficiently access the various types of data, and a rule-based query processor is employed for optimizing query execution. In this paper, we report on our experiences in building BODHI and on its performance characteristics for a representative set of queries.

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