MongoDB Atlas Search and Vector Search
Parent: MongoDB Atlas · researched 2026-05-28T16:41:56.895Z· 50 sources · 10 concepts · skill mongodb-search-ai
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Pagination with Atlas Search
- For deterministic pagination (not skip/limit): [source]
Atlas Vector Search
- See mongodb-atlas-vector-search for the complete reference. Key summary: [source]
Hybrid Search ($rankFusion)
- Combine Atlas Search (BM25) with Vector Search (HNSW) results: [source]
Auto Embedding (Voyage AI)
- Skip the external embedding pipeline: [source]
Search Node Architecture
- For production, use dedicated Search Nodes to isolate Atlas Search / Vector Search workloads from OLTP: [source]
- S20_HIGHCPU_NVME, S30_HIGHCPU_NVME, etc. [source]
- Zero-downtime migration: enable Search Nodes → Atlas replications in background → automatic traffic switch [source]
- See mongodb-atlas-search-nodes for sizing guide [source]
When to Use Atlas Search vs Text Indexes
- Always prefer Atlas Search for production full-text search. Text indexes are only appropriate for very small collections or simple dev prototypes. [source]
Anti-Patterns
- Dynamic true + all fields queried: Dynamic mapping indexes everything, making the index large. Use explicit mappings for production. [source]
- No search node for production Vector Search: Resource contention with OLTP causes latency spikes [source]
- numCandidates too low: numCandidates: limit = minimal recall; use 10-20× limit [source]
- Missing filter fields in vector index: filter in $vectorSearch requires the field to be declared as type: "filter" in the index definition; otherwise falls back to post-filter (much less efficient) [source]
References
Children
- Atlas Search Lucene Architecture (frontier)
- Atlas Vector Search HNSW IVF (frontier)
- Hybrid Search $rankFusion $scoreFusion (frontier)
- RAG Patterns with Vector Search (frontier)
- Atlas Search Analyzers and Tokenizers (frontier)
- Stored Source Performance Optimization (frontier)
- Score Details BM25 Diagnostics (frontier)
- Auto Embedding Voyage AI (frontier)
- Search Nodes Dedicated Infrastructure (frontier)
- Lexical Prefilters for Vector Search (frontier)
Frontier under this node: Atlas Search Analyzers and Tokenizers, Atlas Search Lucene Architecture, Atlas Vector Search HNSW IVF, Auto Embedding Voyage AI, Hybrid Search $rankFusion $scoreFusion, Lexical Prefilters for Vector Search, RAG Patterns with Vector Search, Score Details BM25 Diagnostics, Search Nodes Dedicated Infrastructure, Stored Source Performance Optimization