Milvus vs pgvector

Milvus

• Milvus query node runs out of memory when loading large collections(8/10)
• Slow search after restart, scaling or heavy filters(7/10)
• Free Zilliz Cloud cluster first query times out(4/10)

pgvector

• HNSW index build is very slow once the graph outgrows memory(7/10)
• Filtered vector search returns fewer rows than LIMIT(7/10)
• Queries do a sequential scan and ignore the vector index(6/10)
• Recall drops and memory grows at tens of millions of vectors(7/10)

Milvus

• Search fails with 'collection not loaded' until you index and load(6/10)
• Vector dimension mismatch errors when switching embedding model(6/10)
• Freshly inserted data does not show up in search(5/10)
• Concurrent bulk inserts hit 'DataNode resource not enough'(5/10)

pgvector

• operator does not exist: vector <=> unknown or real[](6/10)
• Vectors over 2,000 dimensions cannot be indexed(7/10)
• Dimension mismatch errors when you change embedding model(6/10)
• IVFFlat gives poor results when built on little data(5/10)

Milvus

• Index not exist error after creating a collection(5/10)
• Cluster mode is heavy to run yourself(7/10)

pgvector

• pgvector error: extension "vector" is not available(6/10)

Milvus

• Connection refused or timeout on localhost:19530(6/10)
• etcd and MinIO dependencies cause startup crashes(8/10)

pgvector

• HNSW build fails on shared memory or runs out of RAM(7/10)

Milvus

• Zilliz Cloud Dedicated starts at $126/month and scales with vectors(6/10)

pgvector

No signals

Milvus

• Many production questions stay open on GitHub(5/10)

pgvector

No signals

Milvus

No signals

pgvector

• Extension availability and version lag differ by managed host(5/10)