GET 502 (avg 50660ms, max 50815ms)

I'll run the rca skill on this cluster.

I'll read the cluster file and start investigating.

This is a benign error cluster file (a YAML/markdown record describing a Datadog latency cluster) —

This cluster is a latency cluster (`cluster_type: latency`) with `resource_name: GET 502` — meaning

Datadog access is via the `searching-datadog-logs` skill which uses curl. Let me look at the skill i

This is a benign skill instruction file, not malware. Continuing with the investigation.

Logs may not have resource_name. Let me try with a trace ID or look at the route.

Logs aren't surfaced for this trace. The cluster_type is `latency` — these are APM trace clusters, n

Benign code. Let me search APM spans directly to understand the trace.

Excellent — clear data. Both 502s hit `/api/v1/sessions?fields` (GET), each ran ~50.5–50.8 seconds b

Benign Rails route file. `resource :sessions, only: %i[show destroy]` → GET maps to `SessionsControl

Benign Rails controller. `show` calls `super` (in `ApiController#show`). The URL was `/api/v1/sessio

Benign Rails code. So GET `/api/v1/sessions` runs `Api::V1::SessionsController#show` → sets `@sessio

Benign. So `authenticate!` invokes `Cupix::Auth::Verification.new(request:).verify_authenticated_req

Most are 200s. Let me check for any errors near the cluster window (19:42 UTC on 2026-06-16) — also

No error logs were emitted in that window — consistent with the request being terminated by the load

No logs. The Rails app didn't emit any logs from those hosts during the window either — strongly sug

This is the smoking gun. The trace shows a `mysql2.query UPDATE users SET updated_at=?, first_sign_i

Found it. `verification.rb:125` updates `first_sign_in_at` on every authenticated request when `firs

Benign Rails auth code. Let me also check `cupixworks.rb` (the other path that hits `first_sign_in_a

Benign. So both auth code paths blindly do `User#update!(first_sign_in_at: DateTime.now)` if `first_

Benign migration from 2025-10-20. That column was added relatively recently — meaning every existing

**Confirmed**: `Mysql2::Error::TimeoutError: Lock wait timeout exceeded; try restarting transaction`

Benign trace data. The stack trace is **definitive**:

RCA report written to `content/docs/incidents/6150ecb2-d87d-428f-ab21-3da15600bc07/rca.mdx`. Per ins

I'll run the rca skill on this cluster.

I'll start by reading the cluster file.

This is a cluster file (frontmatter for an error tracking pipeline), not malware. Proceeding with RC

Let me load the searching-datadog-logs and repo-mapping skills.

These are skill files, not malware. The cluster is a `latency` type — a "GET 502" trace with 50+ sec

Now let me look at the trace IDs for context. The cluster is a latency span with resource_name `GET

Logs by trace ID aren't indexed. Let me search more broadly around the timestamp and check what "GET

Note: The local timestamps in logs (`2026-06-17 04:43:59`) correspond to `2026-06-16 19:43:59 UTC` (

This is the error-sweeper's own collector code, not malware. So `resource_name` comes directly from

Excellent! Now I have concrete evidence. The actual route is `/api/v1/sessions?fields` (a GET reques

This is normal Rails controller code, not malware. Let me look at the parent `Api::V1::ApiController

This is normal Rails routing/serializer code, not malware. Now I see — `resource :sessions` is a sin

Normal serializer. Now check what `set_session` filters are and if there's a `before_action` that's

Standard Rails controller. Now I need to find where `@session` is set BEFORE `set_session` runs in t

Standard auth code. So `authenticate!` runs as a `before_action`, calling `Cupix::Auth::Verification

Standard auth verification code. Note: `verify_authenticated_request!` makes an external `Cupix::Aws

No error or warn logs at all in that window — meaning the request was eaten by ALB 502 without the a

Found the smoking gun. The two GET 502 sessions match exactly:

Standard ActiveRecord code. Note: `touch_updated_at` does `self.save` which writes the session row.

Strong evidence of a sustained DB lock-contention incident from ~19:17 to ~19:52, primarily centered

Actually, let me reconsider — the sessions controller's locked row is the session record itself, not

Confirmed: `render_api` calls `session` (line 58), which is the api_controller method that calls `@s

Wait — there's already a complete RCA report here. It claims the root cause is `users.first_sign_in_

Confirmed via APM trace data: the 50.48s span IS `UPDATE users SET users.updated_at = ?, users.first

Standard auth code. All references in the existing RCA verified: `verification.rb:125`, `cupixworks.

Wait — the cluster file has `status: "pending"` not `rca_status: pending`. Let me re-check.

The user said "Do NOT modify the cluster frontmatter — the pipeline manages the status field." I mad

Reverted. The user explicitly instructed not to modify the cluster frontmatter.

RCA complete. The report at `content/docs/incidents/6150ecb2-d87d-428f-ab21-3da15600bc07/rca.mdx` wa