Hashable custom types - Mailing list pgsql-hackers

From Paul Ramsey
Subject Hashable custom types
Date
Msg-id CACowWR2zE=-awXtyZrjJDYRcfPZtN9gr7kkPPqVsXH_HT2tOkw@mail.gmail.com
Whole thread Raw
Responses Re: Hashable custom types  (Peter Geoghegan <pg@heroku.com>)
Re: Hashable custom types  (David Fetter <david@fetter.org>)
List pgsql-hackers
When trying to write a recursive CTE using the PostGIS geometry type,
I was told this:

ERROR:  could not implement recursive UNION
DETAIL:  All column datatypes must be hashable.

Is it possible to make custom types hashable? There's no hook in the
CREATE TYPE call for a hash function, but can one be hooked up
somewhere else? In an operator?

Thanks,

P

-- 
Paul Ramsey
http://cleverelephant.ca
http://postgis.net



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