On Wed, Mar 11, 2015 at 02:40:16PM +0000, Andrew Gierth wrote: > An issue that comes up regularly on IRC is that text search queries, > especially on relatively modest size tables or for relatively > non-selective words, often misplan as a seqscan based on the fact that > to_tsvector has procost=1. > > Clearly this cost number is ludicrous. > > Getting the right cost estimate would obviously mean taking the cost of > detoasting into account, but even without doing that, there's a strong > argument that it should be increased to at least the order of 100. > (With the default cpu_operator_cost that would make each to_tsvector > call cost 0.25.) > > (The guy I was just helping on IRC was seeing a slowdown of 100x from a > seqscan in a query that selected about 50 rows from about 500.)
Where are we on setting increasing procost for to_tsvector? -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
