postgres-fts-backend

A Django Haystack backend that uses PostgreSQL's built-in full-text search. No external search service required.

Requirements

• Python >= 3.12
• Django >= 5.0
• django-haystack >= 2.8.0
• PostgreSQL

Installation

pip install postgres-fts-backend

Add to INSTALLED_APPS:

INSTALLED_APPS = [
    "django.contrib.postgres",
    "haystack",
    "postgres_fts_backend",
    # ...
]

Set a migration module so the generated search index migrations live in your project rather than inside the installed package:

MIGRATION_MODULES = {
    "postgres_fts_backend": "myapp.search_migrations",
}

Configure Haystack:

HAYSTACK_CONNECTIONS = {
    "default": {
        "ENGINE": "postgres_fts_backend.PostgresFTSEngine",
    },
}

To use a search configuration other than "english":

HAYSTACK_CONNECTIONS = {
    "default": {
        "ENGINE": "postgres_fts_backend.PostgresFTSEngine",
        "SEARCH_CONFIG": "spanish",
    },
}

Other Peculiarities of this backend

Build indexes through models and migrations

python manage.py build_postgres_schema
python manage.py migrate postgres_fts_backend

Run these two commands again whenever you change a SearchIndex definition.

Fuzzy search

Fuzzy queries use PostgreSQL's trigram similarity matching (pg_trgm):

results = SearchQuerySet().filter(author__fuzzy="Janee")

The similarity threshold is controlled by PostgreSQL's pg_trgm.similarity_threshold setting (default 0.3). To adjust it:

ALTER DATABASE mydb SET pg_trgm.similarity_threshold = 0.5;

more_like_this not implemented

PostgreSQL FTS doesn't provide any facilities for this. It could be done, but I just need to think more about it.

spelling_suggestions are not supported