Results from the working setup (Listing B)
==========================================

 id
-----
 500
 600
(2 rows)

                                   QUERY PLAN
--------------------------------------------------------------------------------
 Hash Left Join  (cost=473.04..756.38 rows=14 width=4)
   Hash Cond: (public.items.id = public.items.id)
   Filter: (public.items.id IS NULL)
   ->  Seq Scan on items  (cost=0.00..161.70 rows=10670 width=4)
   ->  Hash  (cost=472.38..472.38 rows=53 width=4)
         ->  Hash Left Join  (cost=189.04..472.38 rows=53 width=4)
               Hash Cond: (public.items.id = public.items.id)
               Filter: (public.items.id IS NULL)
               ->  Seq Scan on items  (cost=0.00..161.70 rows=10670 width=4)
               ->  Hash  (cost=188.38..188.38 rows=53 width=4)
                     ->  Seq Scan on items  (cost=0.00..188.38 rows=53 width=4)
                           Filter: (number = 1)
(12 rows)







Test Query under the faulty setup (Listing C)
=============================================

 id
----
(0 rows)

                                  QUERY PLAN
------------------------------------------------------------------------------
 Nested Loop Left Join  (cost=476.90..1099.08 rows=1 width=4)
   Filter: (public.items.id IS NULL)
   ->  Hash Left Join  (cost=476.90..1079.30 rows=50 width=8)
         Hash Cond: (public.items.id = public.items.id)
         Filter: (public.items.id IS NULL)
         ->  Seq Scan on items  (cost=0.00..351.40 rows=10040 width=4)
         ->  Hash  (cost=351.40..351.40 rows=10040 width=4)
               ->  Seq Scan on items  (cost=0.00..351.40 rows=10040 width=4)
   ->  Index Scan using items_pkey on items  (cost=0.00..0.38 rows=1 width=4)
         Index Cond: (public.items.id = public.items.id)
         Filter: (number = 1)
(11 rows)