Biscuit Documentation

Welcome to the official documentation for Biscuit.

Contents:

Biscuit Index for PostgreSQL

High-Performance Pattern Matching Index for LIKE Queries

What is Biscuit?

Biscuit is a specialized PostgreSQL index access method designed to dramatically accelerate LIKE pattern matching queries. Unlike traditional B-tree or GIN indexes, Biscuit uses bitmap-based character indexing to provide near-instantaneous pattern matching across single or multiple columns.

Key Features

  • Blazing Fast: Optimized for complex LIKE patterns including %, _, prefixes, suffixes, and substrings

  • Multi-Column Support: Query across multiple columns simultaneously with intelligent predicate reordering

  • Aggregate Optimization: Special optimizations for COUNT(*) and EXISTS queries

  • Full CRUD Support: INSERT, UPDATE, DELETE operations with automatic index maintenance

  • Smart Query Planning: Automatic reordering of predicates based on selectivity analysis

  • Memory Efficient: Uses Roaring Bitmaps for compact in-memory representation

Version 2.2.2

⚡ Performance Improvements

  • Refined TID sorting implementation

    Replaced the previous hybrid dense/sparse block radix sorter with a uniform 4-pass radix sort covering the full 32-bit BlockNumber.

    Sorting is now performed using four 8-bit passes, eliminating assumptions about block number density or range.

🛡️ Correctness & Stability

  • Aligned TID comparison with PostgreSQL core

    Replaced custom TID comparison logic with PostgreSQL’s native comparison routine to ensure consistent ordering behavior.

Quick Start

-- Install the extension
CREATE EXTENSION biscuit;

-- Create a Biscuit index
CREATE INDEX idx_products_name ON products 
USING biscuit (name);

-- Query using LIKE patterns
SELECT * FROM products 
WHERE name LIKE '%laptop%';

Documentation Structure

When to Use Biscuit

Perfect For:

  • Text search with wildcards (%product%, item_%)

  • Email/domain filtering (%@company.com)

  • Prefix/suffix matching (admin%, %_test)

  • Multi-column pattern queries

  • High-cardinality string columns

  • Frequent LIKE/ILIKE queries in analytics

Not Ideal For:

  • Full-text search (use tsvector instead)

  • Exact equality matches (B-tree is sufficient)

  • Low-selectivity patterns (single %)

System Requirements

  • PostgreSQL 16 or higher

  • Linux, macOS, or Windows

  • Recommended: CRoaring library for enhanced performance

License

Biscuit is open-source software released under the PostgreSQL License.

Support

Ready to accelerate your pattern matching queries?

👉 Start with the Installation Guide