Tom Lane-2 wrote > FWIW, I get fairly decent performance for cases like this in HEAD > (at least with a GIN index; GIST seems much less able to do well with > short prefixes).
Short or long prefixes seem to be equaly unfavorable. Even with the full length of the words, but queried as prefix I get a runtime of 25342ms compared to 353ms without prefixes: SELECT count(a) FROM t1 WHERE a_tsvector @@ to_tsquery('aaaaa:* & bbbbb:* & ccccc:* & ddddd:*') Total query runtime: 25342 ms "Aggregate (cost=804.02..804.03 rows=1 width=36)" " -> Bitmap Heap Scan on t1 (cost=800.00..804.02 rows=1 width=36)" " Recheck Cond: (a_tsvector @@ to_tsquery('aaaaa:* & bbbbb:* & ccccc:* & ddddd:*'::text))" " -> Bitmap Index Scan on a_tsvector_idx (cost=0.00..800.00 rows=1 width=0)" " Index Cond: (a_tsvector @@ to_tsquery('aaaaa:* & bbbbb:* & ccccc:* & ddddd:*'::text))" Kind Regards Rawi -- View this message in context: http://postgresql.1045698.n5.nabble.com/Index-Usage-and-Running-Times-by-FullTextSearch-with-prefix-matching-tp5759021p5759046.html Sent from the PostgreSQL - sql mailing list archive at Nabble.com. -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql