On 5/16/17 03:19, Ashutosh Bapat wrote: > On Tue, May 16, 2017 at 10:03 AM, amul sul <sula...@gmail.com> wrote: >> On Mon, May 15, 2017 at 9:13 PM, Robert Haas <robertmh...@gmail.com> wrote: >>>>> Collation is only relevant for ordering, not equality. > > While earlier, I thought the same, I am wondering whether this is > true. Don't different collations deem different strings equal e.g one > collation may deem 'aa' and 'AA' as same but other may not. Or is that > encoding problem being discussed in hash functions thread?
The collations we currently support don't do that, unless someone made a custom one. However, we might want to support that in the future. Also, text/varchar comparisons always use strcmp() as a tie-breaker. Again, this might be something to review at some point. But you currently have the citext type that would indeed consider 'aa' and 'AA' equal. But citext also has a hash function in the hash operator class that handles that. So you could look into using that approach. -- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers