## TL;DR
Post-merge regression introduced by #1627 r3 (commit `e2212f50`):
`buildNodeInfoMap` in `cmd/server/neighbor_api.go` ran an uncached
`SELECT … FROM nodes` scan on every call. Folded `first_seen` into the
already-cached `getCachedNodesAndPM` (30s TTL) so the 4 hot handlers
that call `buildNodeInfoMap` no longer pay for a full table scan per
request.
## Before / After
`buildNodeInfoMap` is called by **4 hot handlers**:
- `cmd/server/neighbor_api.go:130`
- `cmd/server/neighbor_api.go:297`
- `cmd/server/neighbor_debug.go:83`
- `cmd/server/node_reach.go:421`
| | Before | After |
|---|---|---|
| `SELECT … FROM nodes` per call | 1 (uncached) | 0 (cache hit) |
| `SELECT … FROM observers` per call | 1 (uncached) | 1 (unchanged) |
| At Cascadia scale (~2600 nodes) | full scan × 4 handlers × N req/s |
one scan / 30s |
## How
- Extended the `getAllNodes` schema probe to also `COALESCE(first_seen,
'')`. Falls back through the existing richest → leanest ladder if the
column is missing.
- `nodeInfo.FirstSeen` is therefore populated for every cached entry in
`getCachedNodesAndPM`.
- `buildNodeInfoMap` drops its second `SELECT` entirely and just copies
`nodeInfo` values out of the cached map.
- Public signature of `buildNodeInfoMap` is unchanged.
`node_reach.go:421` still sees `nodeInfo.FirstSeen` populated, served
from cache.
`cmd/server/store.go` is touched because `getAllNodes` is the only
sensible owner of the `first_seen` SELECT — adding a parallel cache
would duplicate the 30s TTL machinery this fix is designed to leverage.
## Test (red → green)
- Commit 1 (`test:`): `TestBuildNodeInfoMap_FirstSeenIsCached` — calls
`buildNodeInfoMap`, mutates `first_seen` out-of-band via a separate rw
connection, calls it again, and asserts both calls return the same
(cached) value. Fails on `origin/master` (call 2 sees the mutated value,
proving the uncached scan).
- Commit 2 (`perf:`): the fold. Test now passes.
## Refs
Post-merge audit identified this as the only MAJOR finding from #1627;
recommendation was a follow-up hot-fix PR. This is that PR.
---------
Co-authored-by: openclaw-bot <bot@openclaw>
Co-authored-by: openclaw-bot <bot@openclaw.local>
