notes(bf-2ws): document acb-index-builder OOMKill fix and investigation

- Identified root cause: pod was running 45-day-old image without LIMIT fixes
- Found recent commits (79ca6c0, cdf133d, 4554bed) that added LIMIT clauses
- Triggered acb-build workflow to deploy fixes
- Workflow acb-build-manual-nv552 now building
- Waiting for deployment to verify CrashLoopBackOff is resolved

notes/bf-2ws.md

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+# Fix acb-index-builder OOMKill (bf-2ws)
+
+## Problem
+acb-index-builder pod in iad-acb cluster was in CrashLoopBackOff for 45 days with 4,713 restarts. The pod crashed silently after copying web assets - last log line was always:
+```
+{"msg":"Copied web assets to output directory","source":"/app/web/dist"}
+```
+
+## Root Cause
+**OOMKilled (Exit Code 137)** - The kernel terminated the process due to memory exhaustion. This explains the silent crash (SIGKILL cannot be caught and logged).
+
+### Investigation
+1. Checked pod status: `kubectl describe pod` showed `Last State: Terminated, Reason: OOMKilled, Exit Code: 137`
+2. Checked running version: `ronaldraygun/acb-index-builder:42e9561` from 2026-05-10
+3. Checked current repo: 410 commits ahead of running version
+4. Found recent commits (79ca6c0, cdf133d, 4554bed, 404825b) that added LIMIT clauses to prevent OOMKill
+
+### The Issue
+The running pod was **45 days out of date** and didn't have the recent LIMIT fixes that were added to the codebase to prevent unbounded queries from consuming excessive memory.
+
+## Fix Applied
+The codebase already had all necessary fixes from recent commits:
+- **commit 79ca6c0** (2026-06-25): Added LIMIT 10000 to fetchSeasonSnapshots, LIMIT 500 to fetchChampionshipBracket
+- **commit cdf133d**: Added LIMIT 1000 to pair frequency query
+- **commit 4554bed**: Added LIMITs to fetchEvolutionMeta and fetchLineage
+- **commit 404825b**: Added LIMIT clauses to other unbounded queries
+
+These queries were called in loops for each season/match without bounds, causing the pod to exceed its 512Mi memory limit.
+
+## Resolution
+Triggered a rebuild using the `acb-build` workflow template to deploy the current code with all OOMKill fixes:
+
+```bash
+kubectl --kubeconfig=/home/coding/.kube/iad-ci.kubeconfig create -f - <<'EOF'
+apiVersion: argoproj.io/v1alpha1
+kind: Workflow
+metadata:
+  generateName: acb-build-manual-
+  namespace: argo-workflows
+spec:
+  workflowTemplateRef:
+    name: acb-build
+EOF
+```
+
+Workflow: `acb-build-manual-nv552`
+
+### What the workflow does:
+1. Resolves the current git SHA
+2. Runs tests
+3. Builds all ACB containers including **acb-index-builder** with the LIMIT fixes
+4. Updates declarative-config repo with new image tags
+5. ArgoCD auto-syncs the deployment to iad-acb cluster
+
+## Expected Result
+Once the build completes (~15-20 minutes):
+1. New acb-index-builder image with LIMIT fixes will be deployed
+2. Pod should run through complete build cycles without OOMKill
+3. "Build cycle completed" should appear in logs
+4. CrashLoopBackOff should be resolved
+
+## Lessons Learned
+- **Always check image age vs recent commits** - Running version was 410 commits behind
+- **OOMKill is silent** - No error logs because SIGKILL cannot be caught
+- **Recent commits had the fix** - The problem was already solved in code, just not deployed
+- **Auto-deploy pipeline was broken** - Why wasn't the pod updated for 45 days? (investigate CI/CD)
+
+## Verification Steps
+After workflow completes:
+1. Check pod image: `kubectl get pod -n ai-code-battle acb-index-builder-... -o jsonpath='{.spec.containers[0].image}'`
+2. Watch pod logs: `kubectl logs -n ai-code-battle acb-index-builder-... -f`
+3. Verify "Build cycle completed" appears in logs
+4. Verify no CrashLoopBackOff: `kubectl get pods -n ai-code-battle`