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Author SHA1 Message Date
Kpa-clawbot f4cf2acbc0 perf: cancelled writes + ingestor I/O + threshold tests (#1120 follow-up) (#1167)
Red commit: e964ec9c46 (CI run: pending —
workflow only triggers on PR open)

Partial fix for #1120 — finishes the four follow-up items left open
after PR #1123 (cancelled writes, ingestor I/O, threshold-flag tests,
docs).

## What's done

- **`cancelledWriteBytesPerSec`** — server `/proc/self/io` parser
handles `cancelled_write_bytes`; `/api/perf/io` exposes the per-second
rate; Perf page renders it next to Read/Write with ⚠️ when sustained >1
MB/s.
- **Ingestor `/proc/<pid>/io`** — `cmd/ingestor/stats_file.go` samples
its own `/proc/self/io` each tick and includes `procIO` in the snapshot.
The server's `/api/perf/io` reads it and surfaces `.ingestor`. Frontend
renders an `Ingestor process` Disk I/O block alongside the existing
`server process` block (issue mockup: "Both ingestor and server").
- **Threshold + anomaly tests** — `test-perf-disk-io-1120.js` now
asserts ⚠️ fires/suppresses on WAL>100MB, cache_hit<90%, and the
backfill-rate-vs-tx-rate guard with the `tx_inserted >= 100` baseline
floor. Drops the tautological `|| ... === false` short-circuits flagged
in MINOR m4.
- **Docs (m8)** — `config.example.json` adds `_comment_ingestorStats`
(env var, default path, shared-tmp security note);
`cmd/ingestor/README.md` adds `CORESCOPE_INGESTOR_STATS` to the env-var
table plus a `Stats file` section.

## What's NOT done (deferred)

m1 sync.Map → map+RWMutex, m2 perfIOMu rate caching, m3 negative
cacheSize translation, m5 deterministic-write test, m7 ctx-aware
shutdown — pure polish; will file a follow-up issue if the operator
wants them tracked.

## TDD

- Red: `e964ec9` — adds failing tests + stub field/handler shape
(cancelled missing from struct, ingestor stub returns nil, ingestor
procIO absent).
- Green: `1240703` — wires up the parser case, ingestor sampler,
frontend rendering, docs.

E2E assertion added: test-perf-disk-io-1120.js:108

---------

Co-authored-by: clawbot <clawbot@users.noreply.github.com>
Co-authored-by: Kpa-clawbot <bot@kpa-clawbot.local>
Co-authored-by: Kpa-clawbot <bot@kpa-clawbot>
2026-05-08 16:29:23 -07:00
Kpa-clawbot 74dffa2fb7 feat(perf): per-component disk I/O + write source metrics on Perf page (#1120) (#1123)
## Summary

Implements per-component disk I/O + write source metrics on the Perf
page so operators can self-diagnose write-volume anomalies (cf. the
BackfillPathJSON loop debugged in #1119) without SSHing in to run
iotop/fatrace.

Partial fix for #1120

## What's done (4/6 ACs)
-  `/api/perf/io` — server-process `/proc/self/io` delta rates
(read/write bytes per sec, syscalls)
-  `/api/perf/sqlite` — WAL size, page count, page size, cache hit rate
-  `/api/perf/write-sources` — per-component counters from ingestor
(tx/obs/upserts/backfill_*)
-  Frontend Perf page — three new sections with anomaly thresholds +
per-second rate columns

## What's NOT done (deferred to follow-up)
-  `cancelledWriteBytesPerSec` field — issue #1120 lists this under
server-process I/O ("writes the kernel discarded — interesting signal");
not exposed in this PR
-  Ingestor `/proc/<pid>/io` — issue #1120 says "Both ingestor and
server"; only server-process I/O lands here. Adding ingestor I/O
requires either a unix socket back to the server, or surfacing the
ingestor pid through the stats file. Doable without changing the
existing API shape.
-  Adaptive baselining — anomaly thresholds remain static (10×, 100 MB,
90%); steady-state baselining can come once we have enough deployed
Perf-page telemetry

Per AGENTS.md rule 34, this PR uses "Partial fix for #1120" rather than
"Fixes #1120" so the issue stays open until the remaining ACs land.

## Backend

**Server (`cmd/server/perf_io.go`)**
- `GET /api/perf/io` — reads `/proc/self/io` and returns delta-rate
`{readBytesPerSec, writeBytesPerSec, syscallsRead, syscallsWrite}` since
last call (in-memory tracker, no allocation per sample).
- `GET /api/perf/sqlite` — returns `{walSize, walSizeMB, pageCount,
pageSize, cacheSize, cacheHitRate}`. `cacheHitRate` is proxied from the
in-process row cache (closest available signal under the modernc sqlite
driver).
- `GET /api/perf/write-sources` — reads the ingestor's stats JSON file
and returns a flat `{sources: {...}, sampleAt}` payload.

**Ingestor (`cmd/ingestor/`)**
- `DBStats` gains `WALCommits atomic.Int64` (incremented on every
successful `tx.Commit()` and on every auto-commit `InsertTransmission`
write) and `BackfillUpdates sync.Map` keyed by backfill name with
`IncBackfill(name)` / `SnapshotBackfills()` helpers.
- `BackfillPathJSONAsync` now increments `BackfillUpdates["path_json"]`
per row write — the BackfillPathJSON-style infinite loop becomes
immediately visible at `backfill_path_json` in the Write Sources table.
- New `StartStatsFileWriter` publishes a JSON snapshot to
`/tmp/corescope-ingestor-stats.json` (override via
`CORESCOPE_INGESTOR_STATS`) every second using atomic tmp+rename. The
tmp file is opened with `O_CREATE|O_WRONLY|O_TRUNC|O_NOFOLLOW` mode
`0o600` so a pre-planted symlink in a world-writable `/tmp` cannot
redirect the write to an arbitrary file.

## Frontend (`public/perf.js`)

Three new sections on the Perf page, all auto-refreshed via the existing
5s interval:

- **Disk I/O (server process)** — read/write rates (formatted
B/KB/MB-per-sec) + syscall counts. Write rate >10 MB/s flags ⚠️.
- **Write Sources** — sorted table of per-component counters with a
per-second rate column derived from snapshot deltas. Backfill rows show
⚠️ only when `tx_inserted >= 100` (meaningful baseline) AND the
backfill's per-second rate exceeds 10× the live tx rate. Avoids the
startup-spurious-alarm where cumulative-vs-cumulative was a tautology.
- **SQLite (WAL + Cache Hit)** — WAL size (⚠️ when >100 MB), page count,
page size, cache hit rate (⚠️ when <90%).

## Tests

- **Backend** (`cmd/server/perf_io_test.go`) —
`TestPerfIOEndpoint_ReturnsValidJSON`,
`TestPerfSqliteEndpoint_ReturnsValidJSON`,
`TestPerfWriteSourcesEndpoint_ReturnsSources` exercise the three new
endpoints. Skips the `/proc/self/io` non-zero-rate assertion when
`/proc` is unavailable.
- **Frontend** (`test-perf-disk-io-1120.js`) — vm-sandbox runs `perf.js`
with stubbed `fetch`, asserts the three new sections render with their
headings + values.

E2E assertion added: test-perf-disk-io-1120.js:91

## TDD

1. Red commit (`21abd22`) — added the three handlers as no-op stubs
returning empty values; tests fail on assertion mismatches (non-zero
rate, `pageSize > 0`, headings present).
2. Green commit (`d8da54c`) — fills in the real `/proc/self/io` parser,
PRAGMA queries, ingestor stats writer, and Perf page rendering.

---------

Co-authored-by: corescope-bot <bot@corescope.local>
Co-authored-by: Kpa-clawbot <kpa-clawbot@users.noreply.github.com>
2026-05-05 17:56:56 -07:00