Pinecone diagnosis: delete by filter removed nothing

Diagnosis

Symptom

index.delete(filter={...}) returns without error, but subsequent queries still return the records.

Likely cause

Causes in order: wrong namespace (deleted from the default namespace, records live in another), filter matches nothing (same type/name pitfalls as query filters), or the call targeted the wrong index.

Confirm it

1. Fetch one record you expected deleted; print its namespace and metadata.
2. Run a query with the same filter: if it returns records, the filter works and the delete did not target them (namespace/index wrong). If it returns nothing, the filter itself matches nothing.
3. describe_index_stats() per namespace before and after the delete to see which namespace count moved.

Fix

1. Pass the correct namespace explicitly on the delete call.
2. Fix the filter using the fetch output as ground truth.
3. For full-namespace wipes use delete_all with the namespace; it is unambiguous.

Verify the fix

Query after delete and assert the records are gone; check stats counts dropped by the expected number.

Pinecone's data-management guides define namespace-scoped deletes and filter semantics shared with query filters. Verified against live docs 2026-09-26.