Commit Graph
3 Commits
Author SHA1 Message Date
Alex B e6323ec587 fix(store): account path, decode-cache and dedup-key bytes so maxMemoryMB eviction triggers (#2035)
trackedBytes undercounted the packet store by about 2.5x, so packetStore.maxMemoryMB never triggered: a tx was charged at creation, before pickBestObservation set its path, so the byPathHop and spTxIndex costs were never added, and eviction then re-estimated with the path known and subtracted more than had been added, drifting the total downwards. The ParsedDecoded cache, the obsKeys dedup key and several per-observation strings were not estimated at all.

StoreTx.accountedBytes now records what was charged, rechargeTx returns the delta after every pickBestObservation, and eviction subtracts accountedBytes instead of re-estimating. Measured by the author on a production database copy: trackedMB 151 against 402 MB of heap in use before, 351 against 396 MB after, with GC cycles dropping from ~0.71/s to ~0.011/s over 12 h on their instance.

Reviewed by auditing the accounting rather than the arithmetic: all six production pickBestObservation sites recharge, all three subtraction sites read accountedBytes, every recharge site holds s.mu (Load from :857, the two ingest paths at :2778 and :3142 with deferred unlocks), observations are charged only after acceptance, and no charged tx is discarded during the chunk merge. That lock audit is the independent check, because CI's race job covers the ingestor only.

Operator impact, both from the estimate growing rather than any limit moving: where maxMemoryMB is set, eviction now caps the real store size, and the cold load clamp drops about a third of the boot walk (124420 to 84374 packets at 650 MB). Where it is unset, which is the default, the change is inert. docs/go-migration.md claimed the Go server ignored the setting, which was never true, and is corrected here.

Merged by the interim maintainer without a second human reviewer: CI (run 35258839322) plus the review above are the independent checks.
2026-09-17 21:58:16 +02:00
Kpa-clawbotandyou 9e90548637 perf(#800): remove per-StoreTx ResolvedPath, replace with membership index + on-demand decode (#806)
## Summary

Remove `ResolvedPath []*string` field from `StoreTx` and `StoreObs`
structs, replacing it with a compact membership index + on-demand SQL
decode. This eliminates the dominant heap cost identified in profiling
(#791, #799).

**Spec:** #800 (consolidated from two rounds of expert + implementer
review on #799)

Closes #800
Closes #791

## Design

### Removed
- `StoreTx.ResolvedPath []*string`
- `StoreObs.ResolvedPath []*string`
- `TransmissionResp.ResolvedPath`, `ObservationResp.ResolvedPath` struct
fields

### Added
| Structure | Purpose | Est. cost at 1M obs |
|---|---|---:|
| `resolvedPubkeyIndex map[uint64][]int` | FNV-1a(pubkey) → []txID
forward index | 50–120 MB |
| `resolvedPubkeyReverse map[int][]uint64` | txID → []hashes for clean
removal | ~40 MB |
| `apiResolvedPathLRU` (10K entries) | FIFO cache for on-demand API
decode | ~2 MB |

### Decode-window discipline
`resolved_path` JSON decoded once per packet. Consumers fed in order,
temp slice dropped — never stored on struct:
1. `addToByNode` — relay node indexing
2. `touchRelayLastSeen` — relay liveness DB updates
3. `byPathHop` resolved-key entries
4. `resolvedPubkeyIndex` + reverse insert
5. WebSocket broadcast map (raw JSON bytes)
6. Persist batch (raw JSON bytes for SQL UPDATE)

### Collision safety
When the forward index returns candidates, a batched SQL query confirms
exact pubkey presence using `LIKE '%"pubkey"%'` on the `resolved_path`
column.

### Feature flag
`useResolvedPathIndex` (default `true`). Off-path is conservative: all
candidates kept, index not consulted. For one-release rollback safety.

## Files changed

| File | Changes |
|---|---|
| `resolved_index.go` | **New** — index structures, LRU cache, on-demand
SQL helpers, collision safety |
| `store.go` | Remove RP fields, decode-window discipline in
Load/Ingest, on-demand txToMap/obsToMap/enrichObs, eviction cleanup via
SQL, memory accounting update |
| `types.go` | Remove RP fields from TransmissionResp/ObservationResp |
| `routes.go` | Replace `nodeInResolvedPath` with
`nodeInResolvedPathViaIndex`, remove RP from mapSlice helpers |
| `neighbor_persist.go` | Refactor backfill: reverse-map removal →
forward+reverse insert → LRU invalidation |

## Tests added (27 new)

**Unit:**
- `TestStoreTx_ResolvedPathFieldAbsent` — reflection guard
- `TestResolvedPubkeyIndex_BuildFromLoad` — forward+reverse consistency
- `TestResolvedPubkeyIndex_HashCollision` — SQL collision safety
- `TestResolvedPubkeyIndex_IngestUpdate` — maps reflect new ingests
- `TestResolvedPubkeyIndex_RemoveOnEvict` — clean removal via reverse
map
- `TestResolvedPubkeyIndex_PerObsCoverage` — non-best obs pubkeys
indexed
- `TestAddToByNode_WithoutResolvedPathField`
- `TestTouchRelayLastSeen_WithoutResolvedPathField`
- `TestWebSocketBroadcast_IncludesResolvedPath`
- `TestBackfill_InvalidatesLRU`
- `TestEviction_ByNodeCleanup_OnDemandSQL`
- `TestExtractResolvedPubkeys`, `TestMergeResolvedPubkeys`
- `TestResolvedPubkeyHash_Deterministic`
- `TestLRU_EvictionOnFull`

**Endpoint:**
- `TestPathsThroughNode_NilResolvedPathFallback`
- `TestPacketsAPI_OnDemandResolvedPath`
- `TestPacketsAPI_OnDemandResolvedPath_LRUHit`
- `TestPacketsAPI_OnDemandResolvedPath_Empty`

**Feature flag:**
- `TestFeatureFlag_OffPath_PreservesOldBehavior`
- `TestFeatureFlag_Toggle_NoStateLeak`

**Concurrency:**
- `TestReverseMap_NoLeakOnPartialFailure`
- `TestDecodeWindow_LockHoldTimeBounded`
- `TestLivePolling_LRUUnderConcurrentIngest`

**Regression:**
- `TestRepeaterLiveness_StillAccurate`

**Benchmarks:**
- `BenchmarkLoad_BeforeAfter`
- `BenchmarkResolvedPubkeyIndex_Memory`
- `BenchmarkPathsThroughNode_Latency`
- `BenchmarkLivePolling_UnderIngest`

## Benchmark results

```
BenchmarkResolvedPubkeyIndex_Memory/pubkeys=50K     429ms  103MB   777K allocs
BenchmarkResolvedPubkeyIndex_Memory/pubkeys=500K   4205ms  896MB  7.67M allocs
BenchmarkLoad_BeforeAfter                            65ms   20MB   202K allocs
BenchmarkPathsThroughNode_Latency                   3.9µs    0B      0 allocs
BenchmarkLivePolling_UnderIngest                    5.4µs  545B      7 allocs
```

Key: per-obs `[]*string` overhead completely eliminated. At 1M obs with
3 hops average, this saves ~72 bytes/obs × 1M = ~68 MB just from the
slice headers + pointers, plus the JSON-decoded string data (~900 MB at
scale per profiling).

## Design choices

- **FNV-1a instead of xxhash**: stdlib availability, no external
dependency. Performance is equivalent for this use case (pubkey strings
are short).
- **FIFO LRU instead of true LRU**: simpler implementation, adequate for
the access pattern (mostly sequential obs IDs from live polling).
- **Grouped packets view omits resolved_path**: cold path, not worth SQL
round-trip per page render.
- **Backfill pending check uses reverse-map presence** instead of
per-obs field: if a tx has any indexed pubkeys, its observations are
considered resolved.


Closes #807

---------

Co-authored-by: you <you@example.com>
2026-04-20 19:55:00 -07:00
Kpa-clawbotandyou 401fd070f8 fix: improve trackedBytes accuracy for memory estimation (#751)
## Problem

Fixes #743 — High memory usage / OOM with relatively small dataset.

`trackedBytes` severely undercounted actual per-packet memory because it
only tracked base struct sizes and string field lengths, missing major
allocations:

| Structure | Untracked Cost | Scale Impact |
|-----------|---------------|--------------|
| `spTxIndex` (O(path²) subpath entries) | 40 bytes × path combos |
50-150MB |
| `ResolvedPath` on observations | 24 bytes × elements | ~25MB |
| Per-tx maps (`obsKeys`, `observerSet`) | 200 bytes/tx flat | ~11MB |
| `byPathHop` index entries | 50 bytes/hop | 20-40MB |

This caused eviction to trigger too late (or not at all), leading to
OOM.

## Fix

Expanded `estimateStoreTxBytes` and `estimateStoreObsBytes` to account
for:

- **Per-tx maps**: +200 bytes flat for `obsKeys` + `observerSet` map
headers
- **Path hop index**: +50 bytes per hop in `byPathHop`
- **Subpath index**: +40 bytes × `hops*(hops-1)/2` combinations for
`spTxIndex`
- **Resolved paths**: +24 bytes per `ResolvedPath` element on
observations

Updated the existing `TestEstimateStoreTxBytes` to match new formula.
All existing eviction tests continue to pass — the eviction logic itself
is unchanged.

Also exposed `avgBytesPerPacket` in the perf API (`/api/perf`) so
operators can monitor per-packet memory costs.

## Performance

Benchmark confirms negligible overhead (called on every insert):

```
BenchmarkEstimateStoreTxBytes    159M ops    7.5 ns/op    0 B/op    0 allocs
BenchmarkEstimateStoreObsBytes   1B ops      1.0 ns/op    0 B/op    0 allocs
```

## Tests

- 6 new tests in `tracked_bytes_test.go`:
  - Reasonable value ranges for different packet sizes
  - 10-hop packets estimate significantly more than 2-hop (subpath cost)
  - Observations with `ResolvedPath` estimate more than without
  - 15 observations estimate >10x a single observation
- `trackedBytes` matches sum of individual estimates after batch insert
  - Eviction triggers correctly with improved estimates
- 2 benchmarks confirming sub-10ns estimate cost
- Updated existing `TestEstimateStoreTxBytes` for new formula
- Full test suite passes

---------

Co-authored-by: you <you@example.com>
2026-04-15 07:53:32 -07:00