The par2 prune gets 2 min per round (it held the merges back for hours); abandoned ranges past their end are finished

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/services/leases.ts

@@ -52,6 +52,22 @@ class Leases {
     return { range: { id: Number(row.id), group: group.name, start: Number(row.start_id), end: Number(row.end_id), next: Number(row.next_id) }, rules }
   }
 
+  /**
+   * Ranges read to their end whose worker went quiet before finishing them: done. The lease query skips a range past
+   * its end, so one whose finish never came stayed leased for good (a gap range since 2026-10-16 14:03, during the lock
+   * pile-up; LOG.md 2026-10-17 (72)). Its batches are all stored; its spooled chunks go.
+   */
+  async finishAbandoned(): Promise<number> {
+    const { rows } = await db.rawQuery(
+      `UPDATE ranges SET status = 'done', done_at = now()
+       WHERE status = 'leased' AND next_id > end_id AND heartbeat_at < now() - make_interval(secs => ?)
+       RETURNING id`,
+      [coordinatorConfig.leaseTtlSeconds]
+    )
+    for (const { id } of rows) await Spool.remove(Number(id))
+    return rows.length
+  }
+
   async leased(rangeId: number, nodeId: number) {
     const range = await db.from('ranges').where('id', rangeId).first()
     if (!range || range.status !== 'leased' || Number(range.node_id) !== nodeId) throw new LeaseLost(`Range ${rangeId} is not leased to this node`)