Files
meshcore-analyzer/cmd/server/pathhop_eviction_1908_test.go
T
Alex BandClaude Opus 5.5 be6aeffe45 perf(store): drop the duplicate subpath count map (#2163)
## Summary

The subpath index keeps every contiguous run of 2-8 hops from every
stored transmission's path, in two maps:

- `spIndex`: key → count
- `spTxIndex`: key → transmissions containing that subpath, one entry
per occurrence

Both were always updated together (the only production callers were
`addTxToSubpathIndexFull` / `removeTxFromSubpathIndexFull`, which touch
both), so every count equalled `len(spTxIndex[key])`. The existing
`TestSubpathTxIndexPopulated` asserted exactly that. The index therefore
held its 1M+ keys twice.

This PR removes `spIndex`. The two analytics consumers read `len(txs)`,
and the add/remove helpers take only the transaction map. No API
response changes.

No existing upstream issue covers this; it came out of profiling a
production instance where garbage collection was 87% of CPU (30 s CPU
profile: `gcDrain` 39.9 s of 45.9 s sampled) with an 805 MB live heap
against a 1 GiB `GOMEMLIMIT`. That heap profile put 186 MB in this
index; on that instance's 7-day window there are 1.2M distinct subpath
keys (79% seen once) and 3.07M entries.

## Performance

### Go benchmark

`BenchmarkBuildSubpathIndex` builds the index for a synthetic,
production-shaped window: 41k transmissions with path lengths drawn from
the production hop-count histogram, and hops from random walks over a
400-node graph with 3-byte prefixes. That gives 1.48M keys, 85% seen
once (production: 1.2M, 79%). No real data is used. 10 runs each:

```
cpu: AMD Ryzen 5 3600XT 6-Core Processor
                     │    master    │              this PR               │
                     │    sec/op    │   sec/op     vs base               │
BuildSubpathIndex-12    2.157 ± 1%    1.610 ± 5%  -25.33% (p=0.000 n=10)

                     │  retained-B  │  retained-B   vs base              │
BuildSubpathIndex-12   238.5Mi ± 0%   187.7Mi ± 0%  -21.31% (p=0.000 n=10)

                     │     B/op     │     B/op      vs base              │
BuildSubpathIndex-12   572.0Mi ± 0%   465.6Mi ± 0%  -18.61% (p=0.000 n=10)
```

(`retained-B` is the live heap the index keeps after a forced GC: 250.1
MB → 196.8 MB.)

### Staging heap

Live heap after a forced GC (`/debug/pprof/heap?gc=1`), on a staging
host running a copy of a production database and its live MQTT feed,
attributed to the subpath index builder:

| | master | this PR |
|---|---|---|
| subpath index (`buildSubpathIndex`, cum) | 172.4 MB | 116.1 MB |
| packets in memory at the time | 27,521 | 24,086 |
| per packet | 6.27 KB | 4.82 KB (**-23%**) |

The two snapshots were taken minutes apart with different numbers of
packets loaded, hence the per-packet figure; it agrees with the
benchmark's -21%.

The same A/B replay used for the other PRs (30 minutes of real
production API traffic) showed no latency change (p50 10.3 ms vs 10.7
ms, p95 59.5 ms vs 52.9 ms, 0 errors). GC count and CPU were lower in
this run (44 → 28 collections, 13.0% → 9.6% CPU), but runs on this
shared host vary by that much on their own, so no claim is made from
them.

## Tests

- Red commit `ded359ff`: the fixture, `TestSubpathFixtureShape` (keeps
the fixture production-like: 60-95% singleton keys),
`BenchmarkBuildSubpathIndex`, and `TestSubpathIndexRetainedHeap`, which
allows at most 225 MB for the 41k fixture. It fails on `master` with
250.1 MB.
- Green commit `e399c561`: the change. The heap test passes at about 197
MB.
- `make test`: 16 of 16 modules pass; `go test -race` over the subpath,
eviction, path-hop and resolved-index tests passes.

Test changes in the green commit are mechanical, as required for a
structural change:

- struct literals stop setting `spIndex`; where a literal did not set
`spTxIndex` it now does, because appending to a nil map panics where the
old code skipped the transaction map when passed `nil`;
- count assertions read `len(spTxIndex[key])`;
- the old "spIndex and spTxIndex agree" check becomes "no key is kept
with an empty list", which is what keeps `len()` a correct count.

## Review notes

- Removal still takes out one occurrence per subpath occurrence and
deletes a key whose list becomes empty, so `len()` stays equal to the
old count through eviction.
- The store's memory estimate (`perSubpathEntryBytes`) is unchanged
here; accounting accuracy is a separate item.
- No new `map[string]interface{}`.

## SonarLint

SonarQube Community rules (the SonarLint engine) were run on the files
this PR touches, and only issues on lines it adds are listed.

- **Fixed** in `8af9582f`: S3776 (cognitive complexity 16 > 15) in the
test fixture. Path generation is split into graph and hop-count helpers;
the random draws stay in the same order, so the fixture is unchanged.

## Checked against the repo rules

- Rebased onto `master` (`673442cc`). Each red commit was re-run and
still fails on its assertions; each green commit passes (TDD.md).
- `make test`: all 16 modules pass. Frontend suites: all pass except
`test-issue-1956-release-routing.js`, which needs CI's `GITHUB_REF_NAME`
and fails the same way on `master` locally (#2160 addresses it).
- No private data: test fixtures and examples use the codes the existing
tests use (SJC/SFO/LAX, `#be`-style scopes).
- No new `map[string]interface{}`, no hard-coded colours. `git add` was
explicit, and there is one logical change per commit.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

https://claude.ai/code/session_01KaR4xu8gVykQBkH8yG8m6H

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-10 21:21:13 +02:00

188 lines
6.6 KiB
Go

package main
import (
"fmt"
"reflect"
"strings"
"testing"
"time"
)
func TestPathHopEviction1908(t *testing.T) {
for _, mode := range []string{"time-direct", "time-run", "memory-empty-batch", "memory-index-disabled"} {
t.Run(mode, func(t *testing.T) {
now := time.Now().UTC()
store := makeTestStore(8, now.Add(-30*time.Minute), 0)
store.byPayloadType[5] = store.byPayloadType[4]
delete(store.byPayloadType, 4)
store.byPathHop = make(map[string][]*StoreTx)
store.useResolvedPathIndex = mode != "memory-index-disabled"
store.initResolvedPathIndex()
store.retentionHours = 1
if strings.HasPrefix(mode, "memory-") {
store.maxMemoryMB = 1
store.trackedBytes = 8 * 1048576 // The 25% cap evicts the first two.
} else {
for _, tx := range store.packets[:2] {
tx.FirstSeen = now.Add(-2 * time.Hour).Format(time.RFC3339)
}
}
shared := strings.Repeat("a", 64)
expiredOnly := strings.Repeat("b", 64)
retainedOnly := strings.Repeat("c", 64)
expiredScope, retainedScope := "expired-scope", "retained-scope"
hopsSeen := make(map[string]bool)
for i, tx := range store.packets {
*tx.PayloadType = 5 // Non-advert traffic contributes to relay stats.
pk := retainedOnly
tx.ScopeName = &retainedScope
if i < 2 {
pk = expiredOnly
tx.ScopeName = &expiredScope
}
addTxToPathHopIndex(store.byPathHop, tx)
store.indexResolvedPathHops(tx, []string{shared, pk}, hopsSeen)
}
// Repeated observations no longer append the same resolved
// association again (#2108), but eviction must still drop every
// occurrence from a bucket that holds one, so seed duplicates directly.
store.byPathHop[shared] = append(store.byPathHop[shared], store.packets[0], store.packets[7])
store.byPathHop[expiredOnly] = append(store.byPathHop[expiredOnly], store.packets[0])
addTxToPathHopIndex(store.byPathHop, store.packets[0])
// Keep the original backing arrays observable: a shortened slice must
// not hide pointers that keep evicted transmissions alive for the GC.
backingArrays := make(map[string][]*StoreTx, len(store.byPathHop))
for key, list := range store.byPathHop {
backingArrays[key] = list[:cap(list)]
}
before := store.GetRepeaterNodeStatsBatchCached([]string{shared}, 24)[shared].Info
if before.RelayCount24h != 8 || len(before.TransportedScopes) != 2 {
t.Fatalf("fixture must index all transmissions and scopes: %+v", before)
}
var evicted int
if mode == "time-run" {
evicted = store.RunEviction() // No DB: cleanup cannot depend on SQL.
} else {
store.mu.Lock()
if strings.HasPrefix(mode, "memory-") {
evicted = store.EvictStaleWithRP(map[int][]string{})
} else {
evicted = store.EvictStale()
}
store.mu.Unlock()
}
if evicted != 2 {
t.Fatalf("evicted %d transmissions, want 2", evicted)
}
expected := map[string][]int{
"aa": {3, 4, 5, 6, 7, 8},
"bb": {3, 4, 5, 6, 7, 8},
"cc": {3, 4, 5, 6, 7, 8},
shared: {3, 4, 5, 6, 7, 8, 8},
retainedOnly: {3, 4, 5, 6, 7, 8},
}
if len(store.byPathHop) != len(expected) {
t.Errorf("path-hop index has %d keys, want %d (expired-only keys must disappear)", len(store.byPathHop), len(expected))
}
for key, want := range expected {
var ids []int
for _, tx := range store.byPathHop[key] {
ids = append(ids, tx.ID)
}
if !reflect.DeepEqual(ids, want) {
t.Errorf("path-hop bucket %q = %v, want %v", key, ids, want)
}
}
for key, list := range backingArrays {
for _, tx := range list {
if tx != nil && tx.ID <= 2 {
t.Errorf("backing array for %q still retains evicted tx %d", key, tx.ID)
break
}
}
}
if store.relayStatsCache != nil {
t.Error("eviction must invalidate the relay-stats cache")
}
after := store.GetRepeaterNodeStatsBatchCached([]string{shared}, 24)[shared].Info
if after.RelayCount24h != 6 {
t.Errorf("relay count after eviction = %d, want 6", after.RelayCount24h)
}
if !reflect.DeepEqual(after.TransportedScopes, []string{retainedScope}) {
t.Errorf("transported scopes after eviction = %v, want only retained scope", after.TransportedScopes)
}
// A later sweep that removes every survivor must also remove every key.
for _, tx := range store.packets {
tx.FirstSeen = now.Add(-2 * time.Hour).Format(time.RFC3339)
}
if got := store.RunEviction(); got != 6 {
t.Fatalf("final eviction removed %d transmissions, want 6", got)
}
if len(store.byPathHop) != 0 {
t.Errorf("empty store retains %d path-hop keys", len(store.byPathHop))
}
})
}
}
// Benchmark the eviction path with 8 raw and 8 resolved hops per transmission,
// 2 observations each, and 2,048 resolved relays sharing 256 raw-prefix buckets.
// Other secondary indexes are omitted to isolate path-hop cleanup cost. Setup
// is outside the timer; the timed operation includes acquiring the store lock.
func BenchmarkPathHopEviction1908(b *testing.B) {
const hops = 8
pubkeys := make([]string, 2048)
for i := range pubkeys {
pubkeys[i] = fmt.Sprintf("%02x%062x", i%256, i)
}
for _, count := range []int{30000, 100000} {
for _, evictCount := range []int{1, count / 10, count / 4} {
b.Run(fmt.Sprintf("tx=%d/evict=%d", count, evictCount), func(b *testing.B) {
b.ReportAllocs()
for i := 0; i < b.N; i++ {
b.StopTimer()
now := time.Now().UTC()
old := now.Add(-2 * time.Hour).Format(time.RFC3339)
recent := now.Add(-30 * time.Minute).Format(time.RFC3339)
store := &PacketStore{
packets: make([]*StoreTx, count),
byPathHop: make(map[string][]*StoreTx, len(pubkeys)+256),
spTxIndex: make(map[string][]*StoreTx),
retentionHours: 1,
}
hopsSeen := make(map[string]bool, hops*2)
for j := range store.packets {
tx := &StoreTx{ID: j + 1, FirstSeen: recent, parsedPath: make([]string, hops), pathParsed: true}
if j < evictCount {
tx.FirstSeen = old
}
tx.Observations = []*StoreObs{{ID: j * 2}, {ID: j*2 + 1}}
resolved := make([]string, hops)
for k := range resolved {
resolved[k] = pubkeys[(j*17+k*13)%len(pubkeys)]
tx.parsedPath[k] = resolved[k][:2]
}
store.packets[j] = tx
addTxToPathHopIndex(store.byPathHop, tx)
store.addResolvedPubkeysToPathHopIndex(tx, resolved, hopsSeen)
}
b.StartTimer()
store.mu.Lock()
got := store.EvictStale()
store.mu.Unlock()
b.StopTimer()
if got != evictCount {
b.Fatalf("evicted %d transmissions, want %d", got, evictCount)
}
}
b.ReportMetric(float64(count*hops*2), "entries/batch")
})
}
}
}