Announcing the latest Beta release of pgbitmap, available from pgxn and github.

pgbitmap provides a bitmap datatype for Postgres with a full set of functions, operators and aggregates.

This release fixes a number of issues with empty bitmaps and is considered a production release candidate. Any and all feedback is welcomed.

A bitmap is an array of bits, indexed by an integer. Bitmaps provide an efficient means to implement sets of integers. pgbitmap provides functions and operators for:

• creating new bitmaps;
• adding elements to bitmaps;
• removing elements from bitmaps;
• testing for inclusion of elements in bitmaps;
• finding the minimum and maximum bits in bitmaps;
• unioning bitmaps together (set union/logical or);
• intersecting bitmaps (set intersection/logical and);
• subtracting one bitmap from another;
• converting bitmaps to and from textual representations;
• converting bitmaps to and from arrays;
• aggregating bits and bitmaps into bitmaps.

It differs from the standard Postgres bitstring in that it isn't based around bit zero (bitmap(1000000) does not contain 1,000,000 zeroes followed by a 1) and it has more functionality.

It was developed primarily in order to efficiently manage sets of privileges for Virtual Private Database implementations.

Full documentation is available here