Totsquery

Totsquery is a lightweight query engine designed for retrieving data from hierarchical data stores using a compact, text-based query language. It emphasizes low memory usage, streaming results, and predictable performance, making it suitable for embedded systems and small to medium data applications.

Origin and name: The term totsquery is used mainly in educational and experimental contexts. The name is commonly interpreted as a contraction of "text-oriented structured querying" or "text and object tree search query", reflecting its focus on text predicates over tree-structured data. This article describes totsquery as a hypothetical framework used for instructional purposes.

Architecture and features: A typical totsquery implementation consists of a query parser, a compiler that translates queries into a low-level execution plan, and an execution engine that traverses the data store and emits matching results. Features often cited include boolean operators, path-based selectors for nested fields, simple proximity and phrase matching, and streaming delivery of results. The system is usually designed to be schema-agnostic and to work with JSON-like or other tree-structured data.

Syntax and example: Queries combine path-like selectors with predicates. For example, a query might select records where a path 'customers.address.city' equals 'San Jose' and 'order.total' exceeds a threshold, returning only the matching records in a streaming fashion.

Usage and scope: Totsquery is described mainly in tutorials and experimental projects rather than production deployments. It is used to illustrate concepts in query planning, indexing, and streaming retrieval, and as a teaching tool for understanding how query evaluators operate on nested data. Limitations include a small ecosystem, fewer optimizations compared with mature engines, and lack of standardization.

Related topics include XPath, JSONPath, SQL, and tsquery, as points of comparison for nested-data querying and full-text search.