Does Pre-filtering supported?

[qdrddr]

When I filter with a "WHERE" in a query, does filtering applied before or after the semantic search?

[stuhood]

All of the filters defined in your WHERE clause are applied during a single pass over ParadeDB's index. That includes:

• Full text search using @@@ / ||| / etc
• Clauses using other Postgres builtin operators (such as =, >, etc) which can be pushed down to the index: https://docs.paradedb.com/welcome/architecture#custom-scan

[qdrddr]

Thanks for the answer. But I need to know WHEN the filer is logically applied before or after semantic search. This is quite important as both have its own advantages and disadvantages and it’s important to understand which one is used.

thank you!

[stuhood]

As of December 2025, semantic search is accomplished in ParadeDB by https://www.paradedb.com/learn/search-concepts/reciprocal-rank-fusion ... in that case, the filters on the semantic scan and the full text scan are completely independent.

[qdrddr]

I think there's confusion. I have not asked about the full-text scan / BM25 algorithm.
But rather when I want to do a semantic search and apply metadata filters, and was wondering if I can do a vector search with pre- or post-filtering. Like in this example https://lancedb.com/docs/search/filtering/#pre-filtering-with-vector-search

Apologies if I was not clear enough.

[philippemnoel]

We (ParadeDB) make the BM25 index, a Postgres index used for full-text search (keyword, facets). We do ship pgvector and support semantic search with it, but don't do any optimizations there (yet). We may ship improved vector search as part of our index at some point, but for now it is vanilla pgvector.