fix: rebuild FAISS index on vector deletion#4178
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whysosaket merged 1 commit intomem0ai:mainfrom Mar 28, 2026
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The delete() method removed the vector from docstore and index_to_id but never removed it from the actual FAISS index. This caused stale vectors to remain in the index and incorrect search results. Fix by reconstructing remaining vectors and rebuilding the index after deletion, ensuring index_to_id stays contiguous.
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Hi — just a gentle bump on this. Happy to make any changes if needed! |
Himanshu-Sangshetti
approved these changes
Mar 23, 2026
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Himanshu-Sangshetti
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@kartik-mem0 / @whysosaket, LGTM to merge
delete() used to update the docstore and index_to_id but left the underlying FAISS index unchanged, so deleted vectors could still affect search / leave the index out of sync with metadata.
This PR rebuilds the index after a delete so everything stays in line.
I reviewed the implementation and ran tests/vector_stores/test_faiss.py successfully on my machine (all tests passing).
utkarsh240799
approved these changes
Mar 27, 2026
whysosaket
approved these changes
Mar 28, 2026
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Description
The
delete()method inFAISSvector store removed the vector fromdocstoreandindex_to_idbut never removed it from the actual FAISS index. This caused stale vectors to remain searchable and corrupted search results after deletion.Fixes #3787
Type of change
How Has This Been Tested?
Updated
test_deleteto verify that the FAISS index is properly rebuilt after deletion:index.reset()is called to clear the old indexindex.add()is called with remaining vectorsindex_to_idis remapped contiguously (e.g., deleting id at index 0 remaps index 1→0)All 11 existing FAISS tests pass.
Checklist: