> What I can not understand is why the seq scan's estimated cost is > better the index scan's one. It depends on the number of pages in > index/relation. May be the index is heavily bloated? Mm i don't know how to see bloating level. But the index was created by create index on hashcheck using btree (name) after the table population. Sizes: hashes=# select pg_total_relation_size('hashcheck'); pg_total_relation_size ------------------------ 2067701760 (1 row) hashes=# select pg_total_relation_size('hashcheck_name_rev_idx'); pg_total_relation_size ------------------------ 629170176 (1 row) -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance