On 2015-04-19 15:33, Tom Lane wrote: > >> It's possible that in the future someone will implement an optimization >> like this, but I'm not aware of anyone working on that and I wouldn't >> hold my breath. > > Yeah. In principle you could make the planner do this. As Adam Williams > notes nearby, there's a problem with lack of exact consistency between > extract() semantics and straight timestamp comparisons; but you could > handle that by extracting indexable expressions that are considered lossy, What about functions that are simpler such as upper()/lower()? On 9.3, this: `select email from users where lower(first_name) = 'yves'; is not using the index on first_name (Seq Scan on first_name). This should be easy to implement? -- http://yves.zioup.com gpg: 4096R/32B0F416 -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
