biscuit

pg_biscuit : IAM-LIKE pattern matching with bitmap indexing

Overview

Packages

Source

pig build pkg pg_biscuit;		# build rpm/deb

Install

Make sure PGDG and PIGSTY repo available:

pig repo add pgsql -u   # add both repo and update cache

Install this extension with pig:

pig install pg_biscuit;		# install via package name, for the active PG version
pig install biscuit;		# install by extension name, for the current active PG version

pig install biscuit -v 18;   # install for PG 18
pig install biscuit -v 17;   # install for PG 17
pig install biscuit -v 16;   # install for PG 16

Create this extension with:

CREATE EXTENSION biscuit CASCADE; -- requires plpgsql

Usage

Sources:

• PGXN biscuit 2.4.3 distribution
• PGXN 2.4.3 metadata
• PGXN 2.4.3 control file
• PGXN 2.4.3 changelog
• Official documentation

biscuit is an experimental PostgreSQL index access method optimized for pattern filters on text. It targets selective LIKE, ILIKE, NOT LIKE, and NOT ILIKE predicates, including multi-column and expression indexes, while trading additional memory and write work for faster filtering.

Core Workflow

CREATE EXTENSION biscuit;

CREATE INDEX message_body_biscuit_idx
ON message USING biscuit (body);

SELECT id, body
FROM message
WHERE body ILIKE '%timeout%';

Expression indexes work when the query uses the same expression:

CREATE INDEX customer_email_biscuit_idx
ON customer USING biscuit (lower(email));

SELECT *
FROM customer
WHERE lower(email) LIKE '%@example.com';

For predicates spanning several indexed text columns, use a multi-column index and confirm the chosen plan with EXPLAIN (ANALYZE, BUFFERS) on representative data.

Important Objects

• biscuit is the index access method used in CREATE INDEX ... USING biscuit.
• biscuit_operators reports the supported operators.
• biscuit_version and biscuit_build_info expose build information; biscuit_build_info_json returns it as JSON.
• biscuit_status reports the installed build and bitmap configuration.
• biscuit_index_stats and biscuit_index_memory_size inspect an index and its memory footprint.
• biscuit_memory_usage is a view of extension memory use.
• biscuit_has_roaring and biscuit_roaring_version report optional Roaring bitmap support.

Limits and Operations

biscuit is for filtering, not ordered index scans. It does not provide regular-expression or similarity search. Indexes can be larger and more expensive to maintain than a B-tree; benchmark read selectivity, ingest cost, memory use, and vacuum behavior before production use. Keep a conventional index where ordering, equality, uniqueness, or another access method is still required.

The upstream project labels Biscuit as actively developed. PGXN publishes 2.4.3 as a stable distribution, but that archive’s changelog stops at 2.4.2, and its metadata and control file expose SQL extension version 2.4.1. Treat 2.4.3 as a distribution/package refresh: no additional SQL API delta is claimed. The material 2.4.2 change fixes a use-after-free in the index cache plus compiler warnings.