Rates Engine v0.5.0-rc.100

[v0.5.0-rc.100] — 2026-06-01

Tested against Stellar Protocol 23 (Whisk).

Pre-deploy operator note: aggregator restart picks up the cadence-aware gap-detector. No migrations. After deploy, confirm pg_stat_activity shows no concurrent DISTINCT ledger FROM trades scans accumulating across cycles.

Fixed

• Gap-detector no longer pile-drives postgres on huge tables.
  Live r1 incident 2026-05-29: three concurrent SELECT DISTINCT ledger FROM trades WHERE source='sdex' scans accumulated over
  successive gap-detector cycles because the Go-side ctx timeout
  didn't propagate to PostgreSQL — the queries kept running and
  starved trade-insert latency, lighting the slo_latency_burn
  page. Two complementary fixes:
  1. Per-target ScanCadence override. New
     GapDetectorTarget.ScanCadence lets huge-table targets opt
     into a longer scan cadence than the global 30-min interval.
     SDEX trades and soroban_events now scan every 6 hours; light
     targets keep the 30-min cadence for fast signal.
  2. SQL SET LOCAL statement_timeout backstop.
     CountDistinctLedgers and FindPerSourceLedgerGaps now wrap
     their query in a transaction with a 5-min PG-side timeout.
     If Go-side cancellation fails (the F-0020-cousin failure mode
     we just observed), PostgreSQL itself aborts the query —
     in-flight scans can no longer leak across cycles.