On Jan 16, 2013, at 12:23 PM, Robert James <srobertjames@xxxxxxxxx> wrote: > Is there a recommended, high performance method to check for subdomains? > > Something like: > - www.google.com is subdomain of google.com > - ilikegoogle.com is not subdomain of google.com > > There are many ways to do this (lowercase and reverse the string, > append a '.' if not there, append a '%', and do a LIKE). But I'm > looking for one that will perform well when the master domain list is > an indexed field in a table, and when the possible subdomain is either > an individual value, or a field in a table for a join (potentially > indexed). If you've already dealt with any punycode encoding then the lowercased, reversed string works pretty well, either as a (probably trigger-managed) field or as a functional index. If you need to get fancier, you might want to take a look at the approach https://github.com/dimitri/prefix takes. Cheers, Steve -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
