operator @@ is not supported by path; doc says otherwise
От | Anton Voloshin |
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Тема | operator @@ is not supported by path; doc says otherwise |
Дата | |
Msg-id | 5405b243-4523-266e-6139-ad9f80a9d9fc@postgrespro.ru обсуждение исходный текст |
Ответы |
Re: operator @@ is not supported by path; doc says otherwise
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Список | pgsql-docs |
Hello, The documentation for 13 and 14 says in "Geometric Functions and Operators" https://www.postgresql.org/docs/14/functions-geometry.html: > @@ geometric_type → point > Computes the center point. Available for box, lseg, path, polygon, circle. > @@ box '(2,2),(0,0)' → (1,1) However, apparently, this operator does not work for path: > $ psql > psql (14.1) > Type "help" for help. > > postgres=# SELECT @@ path '[(0,0),(0,1)]'; > ERROR: function "path_center" not implemented > postgres=# Same for a closed path: > postgres=# SELECT @@ path '((0,0),(0,1))'; > ERROR: function "path_center" not implemented Quick tests show that other types listed (box, lseg, polygon, circle) are supported, so only the path is extra. This sentence in the documentation came from 791090bd775b (REL_13_STABLE and later). What slightly confuses me is that path_center has been listed in src/include/catalog/pg_operator.dat and pg_proc.dat (and pg_operator.h/pg_proc.h before that) since 3c2d74d2a (1997!), but since a3d284485 (2018) we have a regression test ensuring that "function "path_center" not implemented". The easiest fix is, obviously, removing 'path' from the list in the documentation. Or, if that would be an actual improvement, I could submit a patch to support a path_center as well. Not sure if there is any actual need for that, though: I found this by just goofing around, not because I actually needed to calculate the center for some path. Also, converting to polygon might be a workaround for those who might need that feature. Please let me know if implementing path_center would be a useful addition. P.S. I've sent a report though a submit web form on a documentation web site two days ago, but, apparently, that email was not delivered to this list. Anton Voloshin Postgres Professional, The Russian Postgres Company https://postgrespro.ru
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