Rates Engine v0.5.0-rc.102

[v0.5.0-rc.102] — 2026-06-01

Tested against Stellar Protocol 23 (Whisk).

Pre-deploy operator note: indexer restart picks up the
4-worker parallel drain. No migrations.

Fixed

• PersistEvents parallel drain (4 workers). Live-r1 incident
  2026-06-01: even after rc.101's batch-INSERT fix, the indexer
  cursor advanced at ~1 ledger/min vs ~10/min network rate.
  Root cause: the single-goroutine drain meant only one PG
  roundtrip in flight at a time; the indexer's ProcessLedger
  goroutine was blocked on events <- ev waiting for that one
  worker to drain. With 4 worker goroutines sharing the same
  channel (Go's channel semantics handle concurrent receive
  safely), the events channel drains 4× faster; the existing
  PG pool of 25 conns carries the concurrent INSERTs. Each worker
  maintains its own 200-row trade batch + 200ms flush ticker.
  Per-event ordering within a source is not preserved across
  workers; the trades hypertable's PK (source, ledger, tx_hash, op_index, ts) makes that irrelevant for correctness.