# pisa-engine/pisa

PISA: Performant Indexes and Search for Academia

Repository: https://github.com/pisa-engine/pisa
Canonical: https://ross.abutalabs.com/products/pisa
Homepage: https://pisa-engine.github.io/pisa/book
Language: C++
License: Apache-2.0
License Family: permissive
Topics: inverted-index, search, search-engine, information-retrieval
Last push: 2026-05-06T21:38:20+00:00

## Health v2 (maintenance only)
Score: 59/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 81, release rhythm 8, longevity 100
- inputs: {"age_days": 2898, "days_push": 119, "days_rel": 633, "gap_med": null, "n_releases_24m": 1}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1054, forks 76 (observed 2026-08-28T04:03:24.115662+00:00)

## What it is
PISA is a C++ text search engine and toolkit for building inverted indexes over large document collections. It provides parsing, indexing, sharding, index compression, and query processing algorithms designed for information retrieval research and experimentation.

## Use cases
- build an inverted index over a large document corpus like Wikipedia
- experiment with state-of-the-art index compression methods
- run Boolean AND/OR and ranked queries against an in-memory index
- research faster query processing algorithms for search
- shard and reorder documents for efficient retrieval
- prototype a full-text search engine in C++

## When to choose
- you need a high-performance, open-source search engine for research experiments
- you want to benchmark or compare index compression and query algorithms
- your corpus is large and must be searched from an in-memory inverted index

## When to avoid
- you need a production search service with APIs, facets, and replication out of the box
- you require API stability, as releases make no backwards-compatibility guarantees
- you want a plug-and-play search solution rather than a research toolkit

## Facets
- artifact type: library
- maturity: active
- function: search-engine, parser
- domain: developer-tools
- platform: cross-platform, cli
- tags: inverted-index, index-compression, query-processing, cpp, research, document-reordering, sharding, search, information-retrieval, algorithms, linux, macos

## Member repositories
- pisa-engine/pisa (main) score 59

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:24.115662+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:59:02.622887+00:00, confidence not recorded.
  - readme: https://github.com/pisa-engine/pisa (fetched 2026-08-28T04:03:24.115662+00:00, sha 2dc42862b5f2)
  - homepage: https://pisa-engine.github.io/pisa/book (fetched 2026-08-29T13:00:26.495347+00:00, sha c19f7d01e77f)
- Data as of 2026-08-30T08:39:29.467469+00:00.