INFO:  analyzing "public.zfmt"
INFO:  "zfmt": scanned 40432 of 40432 pages, containing 2172838 live rows and 23031 dead rows; 300000 rows in sample, 2172838 estimated total rows
ANALYZE
(nobody@[local]) [flr]> explain SELECT DISTINCT zf.upc, t.bkkey
FROM zfmt zf LEFT OUTER JOIN ztestbook t ON zf.upc = t.upc
WHERE zf.format NOT IN ('Minidisc', 'Vinyl', 'Laserdisc', 'Memory Card');
                                                  QUERY PLAN
---------------------------------------------------------------------------------------------------------------
 Unique  (cost=1049363.71..1085504.99 rows=4818837 width=19)
   ->  Sort  (cost=1049363.71..1061410.80 rows=4818837 width=19)
         Sort Key: zf.upc, t.bkkey
         ->  Merge Left Join  (cost=57139.45..423876.20 rows=4818837 width=19)
               Merge Cond: (zf.upc = t.upc)
               ->  Index Scan using zfmt_upc_keepers on zfmt zf  (cost=0.00..234872.75 rows=2086169 width=15)
               ->  Index Scan using ztestbook_upc on ztestbook t  (cost=0.00..509648.18 rows=7628206 width=19)
(7 rows)