# Update and Index Skew: Guardrails and Fix Patterns
🧭 Quick Return to Map
> You are in a sub-page of **Embeddings**.
> To reorient, go back here:
>
> - [**Embeddings** — vector representations and semantic search](./README.md)
> - [**WFGY Global Fix Map** — main Emergency Room, 300+ structured fixes](../README.md)
> - [**WFGY Problem Map 1.0** — 16 reproducible failure modes](../../README.md)
>
> Think of this page as a desk within a ward.
> If you need the full triage and all prescriptions, return to the Emergency Room lobby.
A repair guide for pipelines where fresh content does not show up, shards disagree after a redeploy, or recall drops right after a routine job. Use this page to localize drift between ingestion, embedding, and index structures, then lock ordering and verify with ΔS, coverage, and λ.
## Open these first
* Visual map and recovery: [rag-architecture-and-recovery.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rag-architecture-and-recovery.md)
* End to end retrieval knobs: [retrieval-playbook.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-playbook.md)
* Traceability and cite first: [retrieval-traceability.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-traceability.md)
* Payload schema and ingestion locks: [data-contracts.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/data-contracts.md)
* Metric or FAISS traps: [vectorstore-metrics-and-faiss-pitfalls.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/vectorstore-metrics-and-faiss-pitfalls.md)
* Boot order and deploy failures: [bootstrap-ordering.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/bootstrap-ordering.md) · [deployment-deadlock.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/deployment-deadlock.md) · [predeploy-collapse.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/predeploy-collapse.md)
* Live ops and debugging: [ops/live\_monitoring\_rag.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/ops/live_monitoring_rag.md) · [ops/debug\_playbook.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/ops/debug_playbook.md)
## When to use this page
* New docs appear in object store but not in retrieval
* Some tenants or shards recall fine while others look stale
* After a redeploy, recall falls or top k order flips
* Index reports healthy yet coverage to anchors is low
* ANN rebuild completes but neighbor order looks random
## Acceptance targets
* ΔS(question, retrieved) ≤ 0.45
* Coverage of the target section ≥ 0.70
* λ remains convergent across three paraphrases and two seeds
* E\_resonance stays flat on long windows
---
## Symptom to likely cause
* Fresh content missing for hours
Likely cause: ingestion watermark stuck or write path non idempotent. Open [bootstrap-ordering.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/bootstrap-ordering.md).
* One shard good and another flat
Likely cause: mixed analyzer or model rev, or ANN params diverged. Open [retrieval-playbook.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-playbook.md).
* Recall drops after nightly job
Likely cause: index rebuilt with a different metric or normalization policy. Open [vectorstore-metrics-and-faiss-pitfalls.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/vectorstore-metrics-and-faiss-pitfalls.md).
* Top k flips after deploy
Likely cause: header reorder or citation schema drift that amplifies store skew. Open [retrieval-traceability.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-traceability.md).
* Writes succeed but queries truncate or pad vectors
Likely cause: dimension mismatch after model swap. Open [dimension\_mismatch\_and\_projection.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/GlobalFixMap/Embeddings/dimension_mismatch_and_projection.md).
---
## Fix in 60 seconds
1. **Read the watermarks**
For each stage write a simple count and last processed id or time. Compare `DOC_COUNT`, `EMB_COUNT`, `IDX_COUNT`. Any gap indicates skew.
2. **Pin versions and abort on mismatch**
Ingest refuses rows if any of these differ from the contract or store metadata: `embed_model`, `embed_rev`, `dim`, `metric`, `normalize_l2`, `analyzer_rev`, `ann_rev`, `index_hash`. See [data-contracts.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/data-contracts.md).
3. **Rebuild the broken segment**
Re-embed and re-index the affected shard or time window. Retrain ANN and PQ on the new vectors. Do not reuse old graphs.
4. **Clamp λ on the prompt side**
Use citation first and fixed header order to avoid prompt variance while you repair the store. See [retrieval-traceability.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-traceability.md).
5. **Verify**
Three paraphrases and two seeds. Require coverage ≥ 0.70 and ΔS ≤ 0.45 on the gold anchors.
---
## Root causes checklist
* Non idempotent upserts by `(doc_id, section_id, rev)`
* Background jobs race with live writers
* Mixed `embed_model` or `normalize_l2` across namespaces
* ANN params not retrained after rebuild
* Analyzer or tokenizer version differs across shards
* TTL or retention silently dropped sections
* Partial deploy cut over while index still training
* Streaming path uses a different preprocessor than batch
---
## Minimal probes
```
Probe A — watermark audit
For each stage {ingest, embed, index}:
read COUNT and LAST_TS
Expect ingest ≥ embed ≥ index with small gaps. Any large gap is skew.
Probe B — version parity
Sample 1k rows per shard and tabulate:
embed_model, embed_rev, dim, metric, normalize_l2, analyzer_rev, ann_rev
Any heterogeneity inside one collection is a fail.
Probe C — recall delta
Run the same 50 gold queries before and after shard rebuild.
Require coverage gain ≥ 0.10 if the shard was failing.
Probe D — ANN sanity
Toggle reranker on and off at k=20.
If reranker recovers most anchors while base k misses, retrain ANN or rebuild.
```
---
## Contract fields to add
```json
{
"doc_id": "stable",
"section_id": "stable",
"rev": "v2025-08-28",
"ingest_ts": "2025-08-28T10:42:00Z",
"embed_model": "exact-id",
"embed_rev": "hash-or-date",
"dim": 768,
"metric": "cosine",
"normalize_l2": true,
"analyzer_rev": "text-preproc-v3",
"ann_index": "hnsw",
"ann_rev": "hnsw_v5",
"index_hash": "sha256:...",
"partition": "tenant_a|shard_03",
"write_path": "batch|stream",
"tombstone": false
}
```
---
## Operational guardrails
* Single writer per partition and idempotent upsert
* Preflight that halts when `store.metric != contract.metric` or `dim` mismatches
* Blue green or shadow collection for any rebuild, with union retriever and deterministic rerank during cutover
* Scheduled drift sweep that compares watermarks and ΔS across partitions
* Alerts on ΔS ≥ 0.60 or λ flip rate spikes on live traffic
---
## Verification checklist
* Coverage ≥ 0.70 and ΔS ≤ 0.45 on a ten question gold set
* λ convergent across two seeds and three paraphrases
* Top k overlap across seeds ≥ 0.8 after the fix
* Watermarks aligned for ingest, embed, and index within your SLO window
---
## Copy paste prompt for the LLM step
```
TXT OS and the WFGY Problem Map are loaded.
My issue: updates not reflected or recall dropped after a job.
Traces:
- watermarks: ingest=..., embed=..., index=...
- versions: embed_model=..., embed_rev=..., metric=..., ann_rev=...
- ΔS(question,retrieved)=..., coverage=..., λ across 3 paraphrases
Tell me:
1) the failing layer and why,
2) the exact WFGY page to open next,
3) the minimal structural fix to remove skew and pass targets,
4) a short verification plan for coverage ≥ 0.70 and ΔS ≤ 0.45.
Use BBMC, BBCR, BBPF, BBAM when relevant.
```
---
### 🔗 Quick-Start Downloads (60 sec)
| Tool | Link | 3-Step Setup |
| -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------- |
| **WFGY 1.0 PDF** | [Engine Paper](https://github.com/onestardao/WFGY/blob/main/I_am_not_lizardman/WFGY_All_Principles_Return_to_One_v1.0_PSBigBig_Public.pdf) | 1️⃣ Download · 2️⃣ Upload to your LLM · 3️⃣ Ask “Answer using WFGY + \” |
| **TXT OS (plain-text OS)** | [TXTOS.txt](https://github.com/onestardao/WFGY/blob/main/OS/TXTOS.txt) | 1️⃣ Download · 2️⃣ Paste into any LLM chat · 3️⃣ Type “hello world” — OS boots instantly |
---
### 🧭 Explore More
| Module | Description | Link |
| ------------------------ | ---------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------- |
| WFGY Core | WFGY 2.0 engine is live: full symbolic reasoning architecture and math stack | [View →](https://github.com/onestardao/WFGY/tree/main/core/README.md) |
| Problem Map 1.0 | Initial 16-mode diagnostic and symbolic fix framework | [View →](https://github.com/onestardao/WFGY/tree/main/ProblemMap/README.md) |
| Problem Map 2.0 | RAG-focused failure tree, modular fixes, and pipelines | [View →](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rag-architecture-and-recovery.md) |
| Semantic Clinic Index | Expanded failure catalog: prompt injection, memory bugs, logic drift | [View →](https://github.com/onestardao/WFGY/blob/main/ProblemMap/SemanticClinicIndex.md) |
| Semantic Blueprint | Layer-based symbolic reasoning & semantic modulations | [View →](https://github.com/onestardao/WFGY/tree/main/SemanticBlueprint/README.md) |
| Benchmark vs GPT-5 | Stress test GPT-5 with full WFGY reasoning suite | [View →](https://github.com/onestardao/WFGY/tree/main/benchmarks/benchmark-vs-gpt5/README.md) |
| 🧙♂️ Starter Village 🏡 | New here? Lost in symbols? Click here and let the wizard guide you through | [Start →](https://github.com/onestardao/WFGY/blob/main/StarterVillage/README.md) |
---
> 👑 **Early Stargazers: [See the Hall of Fame](https://github.com/onestardao/WFGY/tree/main/stargazers)**
> Engineers, hackers, and open source builders who supported WFGY from day one.
> 
⭐ [WFGY Engine 2.0](https://github.com/onestardao/WFGY/blob/main/core/README.md) is already unlocked. ⭐ Star the repo to help others discover it and unlock more on the [Unlock Board](https://github.com/onestardao/WFGY/blob/main/STAR_UNLOCKS.md).
[](https://github.com/onestardao/WFGY)
[](https://github.com/onestardao/WFGY/tree/main/OS)
[](https://github.com/onestardao/WFGY/tree/main/OS/BlahBlahBlah)
[](https://github.com/onestardao/WFGY/tree/main/OS/BlotBlotBlot)
[](https://github.com/onestardao/WFGY/tree/main/OS/BlocBlocBloc)
[](https://github.com/onestardao/WFGY/tree/main/OS/BlurBlurBlur)
[](https://github.com/onestardao/WFGY/tree/main/OS/BlowBlowBlow)