_pull_item query can be executed over non-existent q_names about pq HOT 1 OPEN

                                                     QUERY PLAN
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 Update on tasks  (cost=115.98..124.00 rows=1 width=1122)
   CTE candidates
     ->  Limit  (cost=0.42..115.24 rows=2 width=740)
           ->  Index Scan using priority_idx2 on tasks tasks_1  (cost=0.42..4478.40 rows=78 width=740)
                 Index Cond: (q_name = 'faxer'::text)
   CTE selected
     ->  Limit  (cost=0.07..0.07 rows=1 width=24)
           ->  Sort  (cost=0.07..0.07 rows=1 width=24)
                 Sort Key: candidates.schedule_at NULLS FIRST, candidates.expected_at NULLS FIRST
                 ->  CTE Scan on candidates  (cost=0.00..0.06 rows=1 width=24)
                       Filter: (pg_try_advisory_xact_lock(id) AND ((schedule_at <= now()) OR (schedule_at IS NULL)))
   CTE next_timeout
     ->  Aggregate  (cost=0.06..0.07 rows=1 width=8)
           ->  CTE Scan on candidates candidates_1  (cost=0.00..0.05 rows=1 width=8)
                 Filter: (schedule_at >= now())
   InitPlan 4 (returns $3)
     ->  CTE Scan on next_timeout  (cost=0.00..0.02 rows=1 width=8)
   InitPlan 5 (returns $4)
     ->  CTE Scan on selected  (cost=0.00..0.02 rows=1 width=8)
   ->  Index Scan using tasks_pkey on tasks  (cost=0.56..8.58 rows=1 width=1122)
         Index Cond: (id = $4)
         Filter: (dequeued_at IS NULL)
(22 rows)