gistfile1.txt

Hash Join  (cost=10.73..56645.36 rows=1176859 width=309) (actual time=0.109..917.785 rows=1176894 loops=1)
  Hash Cond: ((hmr.serial_from_message)::text = (hm.serial_number)::text)
  ->  Seq Scan on heat_meter_reading hmr  (cost=0.00..53501.59 rows=1176859 width=163) (actual time=0.006..263.052 rows=1176894 loops=1)
  ->  Hash  (cost=6.99..6.99 rows=299 width=146) (actual time=0.090..0.092 rows=299 loops=1)
        Buckets: 1024  Batches: 1  Memory Usage: 40kB
        ->  Seq Scan on heat_meter hm  (cost=0.00..6.99 rows=299 width=146) (actual time=0.006..0.043 rows=299 loops=1)
Planning Time: 0.483 ms
Execution Time: 963.897 ms