Re: EXLCUDE constraints and Hash indexes

>>>>> "Jeff" == Jeff Janes <jeff(dot)janes(at)gmail(dot)com> writes:

Jeff> From: https://www.postgresql.org/docs/9.4/static/sql-createtable.html

Jeff> "The access method must support amgettuple (see Chapter 55); at
Jeff> present this means GIN cannot be used. Although it's allowed, there is
Jeff> little point in using B-tree or hash indexes with an exclusion
Jeff> constraint, because this does nothing that an ordinary unique
Jeff> constraint doesn't do better. So in practice the access method will
Jeff> always be GiST or SP-GiST."

I also recently found a case where using btree exclusion constraints was
useful: a unique index on an expression can't be marked deferrable, but
the equivalent exclusion constraint can be.

--
Andrew (irc:RhodiumToad)