On 30 December 2015 at 04:21, Hiroyuki Sato <hiroys...@gmail.com> wrote:
> 2015年12月29日(火) 4:35 Jeff Janes <jeff.ja...@gmail.com>: > >> >> > >> But, the planner refuses to use this index for your query anyway, >> because it can't see that the patterns are all left-anchored. >> >> Really, your best bet is refactor your url data so it is stored with a >> url_prefix and url_suffix column. Then you can do exact matching >> rather than pattern matching. >> > > I see, exact matching faster than pattern matting. > But I need pattern match in path part > (ie, http://www.yahoo.com/a/b/c/... ) > I would like to pattern match '/a/b/c' part. > If your pattern matching is as simple as that, then why not split the /a/b/c/ part out as mentioned by Jeff? Alternatively you could just write a function which splits that out for you and returns it, then index that function, and then just include a call to that function in the join condition matching with the equality operator. That'll allow hash and merge joins to be possible again. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
