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🏷️Use Metadata Filtering in Vector Search

Contrast pre-filter, post-filter, and partitioned-index strategies for metadata-aware vector search on the same dataset so the recall failure mode becomes visible, then design a metadata schema for a multi-tenant RAG that needs sub-100ms queries.

Applied14 drops~2-week path · 5–8 min/daytechnology

Phase 1Why a tenant_id Filter Silently Destroys Recall in Vector Search

See why a tenant_id post-filter silently destroys recall

4 drops

  1. The where-clause that returns zero rows for a tenant whose docs are right there

    6 min

    The where-clause that returns zero rows for a tenant whose docs are right there

  2. Make a 5M-vector index with one small tenant and watch post-filter return zero

    7 min

    Make a 5M-vector index with one small tenant and watch post-filter return zero

  3. Three filter strategies, ranked by what they cost and what they save

    6 min

    Three filter strategies, ranked by what they cost and what they save

  4. The small tenant you'll torture all week — and why one is enough

    5 min

    The small tenant you'll torture all week — and why one is enough

Phase 2Pre-Filter and Post-Filter Head-to-Head on the Same Query

Run pre-filter and post-filter side by side and compare

5 drops

  1. Run post-filter on the small tenant and capture the empty-set baseline

    6 min

    Run post-filter on the small tenant and capture the empty-set baseline

  2. Enable pre-filter and watch the same query return the right answer

    7 min

    Enable pre-filter and watch the same query return the right answer

  3. Post-filter vs pre-filter on the same query — and write down what you see

    6 min

    Post-filter vs pre-filter on the same query — and write down what you see

  4. Pre-filter isn't free — three places it bites back at scale

    6 min

    Pre-filter isn't free — three places it bites back at scale

  5. Filter selectivity tells you whether pre-filter or post-filter wins this query

    7 min

    Filter selectivity tells you whether pre-filter or post-filter wins this query

Phase 3Partitioned Indexes, Namespaces, and Sharding by Metadata Key

Map partitioned indexes, namespaces, and when to shard by metadata

4 drops

  1. Partitioned indexes turn the filter into a routing decision

    6 min

    Partitioned indexes turn the filter into a routing decision

  2. Namespaces, shards, and the spectrum between one index and N indexes

    7 min

    Namespaces, shards, and the spectrum between one index and N indexes

  3. Sub-100ms latency budgets ration the filter strategies you can afford

    7 min

    Sub-100ms latency budgets ration the filter strategies you can afford

  4. Three signals tell you which filter strategy each query needs

    6 min

    Three signals tell you which filter strategy each query needs

Phase 4Design a Metadata Schema for a Sub-100ms Multi-Tenant RAG

Design a metadata schema for a sub-100ms multi-tenant RAG

1 drop

  1. Design a metadata schema for a multi-tenant RAG that needs sub-100ms queries

    9 min

    Design a metadata schema for a multi-tenant RAG that needs sub-100ms queries

Frequently asked questions

What is metadata filtering in vector search and why does it matter?
This is covered in the “Use Metadata Filtering in Vector Search” learning path. Start with daily 5-minute micro-lessons that build from fundamentals to hands-on application.
What is the difference between pre-filter and post-filter in vector search?
This is covered in the “Use Metadata Filtering in Vector Search” learning path. Start with daily 5-minute micro-lessons that build from fundamentals to hands-on application.
Why does post-filtering on tenant_id return zero matches even when matches exist?
This is covered in the “Use Metadata Filtering in Vector Search” learning path. Start with daily 5-minute micro-lessons that build from fundamentals to hands-on application.
When should I use partitioned indexes or namespaces instead of metadata filters?
This is covered in the “Use Metadata Filtering in Vector Search” learning path. Start with daily 5-minute micro-lessons that build from fundamentals to hands-on application.
How do I design a metadata schema for a multi-tenant RAG that needs sub-100ms queries?
This is covered in the “Use Metadata Filtering in Vector Search” learning path. Start with daily 5-minute micro-lessons that build from fundamentals to hands-on application.

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