Replay

Replay re-drives per-group delivery state. The event log is never copied or deleted.

Preferred: new group + start cursor

:ok = Rheo.create_group("market-events", "risk-replay", start_after: 20)

{:ok, leases} = Rheo.fetch("market-events", "risk-replay", limit: 50)
# Only sequences after 20 — production "risk" is untouched

Use this when you want a parallel consumer without disturbing live progress.

Reopen an existing group

:ok = Rheo.replay("market-events", "risk", from_sequence: 0)

Or filter which events become available again:

:ok =
  Rheo.replay("market-events", "risk",
    query: [type: "curve_update", currency: "EUR"]
  )

Expect duplicates relative to earlier ACKs — handlers must stay idempotent.

Destructive reset

# Requires explicit confirmation
:ok =
  Rheo.reset_group("market-events", "risk",
    confirm: true,
    start_after: 25
  )

Without confirm: true, reset is rejected. Events remain in the log; only this group's delivery state is wiped / repositioned. Other groups are unaffected.

Choosing a path

Design details: ADR 015 and the tutorial Search and replay.