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Show HN: Find stale, orphaned, deleted-but-retrievable RAG vectors

RAGproof released an open-source tool, rag-staleness-check, that performs read-only staleness, orphan, duplicate, and retrievability checks on a single pgvector, Qdrant, or Chroma index. The tool, installable via pip for Python 3.10+, reports findings to stdout and a JSON file, skipping checks with missing inputs rather than showing misleading zeros. It is the free half of RAGproof's paid audit, which cross-validates findings against a git-history-derived ledger across all three engines.

read7 min views19 publishedAug 6, 2026
Show HN: Find stale, orphaned, deleted-but-retrievable RAG vectors
Image: Michielbdejong (auto-discovered)

Read-only staleness / orphan / duplicate / retrievability checks for a single pgvector, Qdrant or Chroma index - the open-source half of the RAGproof "decayed RAG index" teardown (full writeup + multi-engine ledger-verified methodology).

This tool runs against your own already-indexed vector database and tells you:

staleness- indexed chunks whose source document has since changed (needs a manifest withlast_modified

per document and the engine itself storing a per-row last-modified value)orphans- indexed chunks whose source document no longer exists in your manifest at all** duplicates**- near-identical chunks (cosine similarity ≥ threshold, default 0.98), plus an exact-hash pass if you store a per-chunk content hashretrievable-after-delete- a basic probe: for ids you believe are deleted, is the vector still physically retrievable by id (storage-layer persistence), and does it still surface in top-k search results (functional leak)?

It's read-only - it never calls a write/delete/upsert method on your engine. See Read-only guarantee below for how that's enforced, and its limits.

This is the single-engine, ledger-free, self-serve slice. It doesn't include:

  • multi-engine orchestration (run it once per engine yourself)
  • the GDPR Article-17 reporting pack (signed evidence, verifiable-erasure report)
  • engine-specific deep checks (pgvector dead-tuple/VACUUM detail, Qdrant optimizer-threshold detail, Chroma on-disk HNSW growth)
  • a ledger-based precision/recall harness - there's no ground truth here, this tool reports what it finds, not how accurate the finding is

Those live in the private, paid RAGproof audit, which cross-validates every finding against a git-history-derived ground-truth ledger across all three engines simultaneously.

pip install rag-staleness-check              # pgvector only
pip install "rag-staleness-check[qdrant]"     # + Qdrant
pip install "rag-staleness-check[chroma]"     # + Chroma
pip install "rag-staleness-check[all]"        # everything

Or, without installing:

pipx run rag-staleness-check --engine pgvector --dsn "$DSN" --source ./docs_manifest.json

Requires Python 3.10+.

rag-staleness-check \
  --engine pgvector \
  --dsn "postgresql://readonly_user:pw@localhost:5432/mydb" \
  --pg-table chunks \
  --pg-doc-id-column doc_id \
  --pg-last-modified-column last_modified \
  --pg-content-hash-column content_sha256 \
  --source ./docs_manifest.json \
  --deleted-ids ./deleted_ids.json \
  --out findings.json

This prints a scorecard to stdout and writes the full result to --out

(default findings.json

). If a check is missing a required input - no --source

, no per-row metadata configured, no --deleted-ids

  • it reports "skipped": true

with a reason instead of silently showing a misleadingly clean 0%.

| Engine | --dsn format | Example | |---|---|---| pgvector | Postgres DSN | postgresql://user:pw@localhost:5432/db | qdrant | Base URL | http://localhost:6333 | chroma | host:port | localhost:8000 |

Your table/column or payload/metadata field names are your own - this tool doesn't assume anything about your schema beyond what you tell it via flags:

pgvector (--pg-*

): --pg-table

(required), --pg-id-column

(default id

), --pg-vector-column

(default embedding

), --pg-doc-id-column

, --pg-last-modified-column

, --pg-content-hash-column

. The last three are optional, and leaving them out is exactly what makes staleness / orphans / the duplicates check's exact-hash pass report skipped

/ zero-coverage.

Qdrant / Chroma (--collection

required, plus payload/metadata field names): --doc-id-field

(default doc_id

), --last-modified-field

(default last_modified

), --content-hash-field

(default content_sha256

).

A JSON file describing what documents should exist - this is the join key for staleness and orphans. There's no ledger in this tool; the manifest is the only source of truth about "what's current."

{
  "manifest_version": 1,
  "documents": [
    {
      "doc_id": "handbook/engineering/on-call.md",
      "last_modified": "2026-06-01T00:00:00Z",
      "content_sha256": "optional, doc-level, informational only"
    }
  ]
}

doc_id

has to match whatever value your own ingestion pipeline wrote into each indexed chunk's doc-id column/field (see schema mapping above). last_modified

is only needed if you want the staleness check to run. content_sha256

here is doc-level and purely informational - it isn't the input to duplicate detection (see below). Full example at examples/docs_manifest.json.

A JSON array of ids you believe are deleted:

["chunk-abc123", "chunk-def456"]

For each one, this checks whether the vector is still retrievable by id (storage-layer persistence) and, if so, whether it still shows up in a top-k self-query (functional leak). The distinction matters: per EDPB Guidelines 05/2019, erasure has to be verifiable and irreversible - suppressing a record from search results isn't enough on its own if the underlying vector is still there. findings.json

's retrievable.framing

field spells this out every run.

This tool never calls a write/delete/upsert method on your engine, and that's enforced two ways:

Structurally, via a static test-walks the actual syntax tree of every file undertests/test_no_write_methods.py

src/rag_staleness_check/

and fails the build if any write/delete/ upsert-shaped method gets called, or any SQL write statement is passed toexecute()

/executemany()

. Not a substring grep - that would false-positive on this very README and on docstrings - it parses real syntax.At runtime, for pgvector- every connection opens withSET default_transaction_read_only = on

, andrag_staleness_check.readonly.assert_pg_read_only()

re-checksSHOW default_transaction_read_only

before any query runs, refusing to proceed if it isn't'on'

. That's defense-in-depth against a connection pooler (e.g. PgBouncer) silently swallowing the session-levelSET

.

Qdrant and Chroma don't give a client-exposed way to check "is this session/API key read-only" - that's deployment-side RBAC, not something either client library reports. For those two engines, enforcement is the static test above plus your own deployment-side scoping: connect with a read-only-scoped API key/token if your engine supports one. There's no runtime assertion for Qdrant/Chroma equivalent to pgvector's - flagging that here rather than implying parity where there isn't any.

For extra assurance on pgvector, connect through a locked-down role instead of relying on this tool alone:

CREATE ROLE rag_staleness_check_readonly NOSUPERUSER LOGIN PASSWORD '...';
GRANT CONNECT ON DATABASE mydb TO rag_staleness_check_readonly;
GRANT USAGE ON SCHEMA public TO rag_staleness_check_readonly;
GRANT SELECT ON chunks TO rag_staleness_check_readonly;

No default telemetry. Nothing is collected or sent automatically. --share-anonymous-scorecard

is an explicit opt-in that prints the exact anonymized payload (aggregate counts + engine type only - never your dsn, hostnames, doc_ids, or chunk_ids) that would be shared. There's no backend configured yet, so nothing actually goes over the network - the flag is reserved for a future opt-in submission endpoint. DO_NOT_TRACK

in the environment, if set, forces this off even if the flag is passed.

Separately, this tool disables chromadb's own client-side telemetry (anonymized_telemetry=False

) when connecting to Chroma. The chromadb

package ships its own default-on PostHog-based telemetry, independent of anything above - leaving it enabled would quietly break the "no default telemetry" promise for --engine chroma

users even though this tool's own code never phones home.

One cosmetic wrinkle: on chromadb==0.6.3

, the setting takes effect (verified via client._system.settings.anonymized_telemetry is False

), but a startup event (ClientStartEvent

) still tries to fire through a code path that doesn't consistently honor it, and throws capture() takes 1 positional argument but 3 were given

while constructing the call - before any request is made. You may see this line printed; it doesn't mean anything was sent.

Duplicate detection's exact-hash pass needs a per-chunk content hash stored in your engine (--pg-content-hash-column

/--content-hash-field

). Without one, it falls back to cosine-ANN only, and awarning

field in theduplicates

check says so rather than staying silent about it.Chroma's only reports a live count, intentionallysnapshot_stats()

  • no on-disk HNSW-directory-size measurement. (The private RAGproof audit's dev-environment build of this used a docker exec du

trick against a known-local container; that has no equivalent against a real third-party deployment, so it isn't shipped here.)

  • no on-disk HNSW-directory-size measurement. (The private RAGproof audit's dev-environment build of this used a may warn if your installed client's minor version differs from your server's by more than 1 (e.g. "Qdrant client version 1.18.0 is incompatible with server version 1.15.5"). Non-fatal - the check still runs - but if it's noisy, pinqdrant-client

's own compatibility checkqdrant-client

to match your server's minor version yourself.This tool reports counts and pairs, not precision/recall. There's no ground truth available client-side to score itself against - that's what the private, ledger-based audit is for.Duplicate detection needs a retrievable vector per candidate- a chunk with no vector returned byget_vector

is silently excluded from the cosine-ANN pass (nothing to query with), not counted as "not a duplicate."

qdrant-client

andchromadb

areoptional extras(pip install rag-staleness-check[qdrant]

/[chroma]

/[all]

) so a pgvector-only user doesn't have to pull in Chroma's heavier transitive dependencies.- Neither is pinned to an exact version. This tool connects to a third party's already-running deployment, whose server version is out of its control, so hard-pinning - unlike a project that ships and controls its own Docker images - would just break users on anything else.

Apache-2.0. See LICENSE. Independent of any other RAGproof project's license.

Issues and PRs welcome. Not yet implemented: a --method minhash

surface-text-based duplicate detection mode (via datasketch

) as an alternative/complement to the cosine-embedding approach above - PRs welcome.

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