On Thu, Sep 17, 2015 at 9:14 AM, pinker <pin...@onet.eu> wrote: > I've tried to write audit trigger which fires only when data changed, so I > used "WHEN (OLD.* IS DISTINCT FROM NEW.*)" clause as described in > documentation > <http://www.postgresql.org/docs/9.4/static/sql-createtrigger.html>. > Should this clause be independent from data type? because an error occurs > when I'm trying to modify row with point data type: *ERROR: could not > identify an equality operator for type point* Example:
Why the point (and geometric operators in general) use "=~" - w/ meaning "same as?" - instead of (as opposed to in addition to) a regular "=" - w/ meaning "equals?" - I cannot say but because of this when IS DISTINCT tries to locate a operator/function to use for its equality comparison it fails. The main problem seems to be indexing and secondarily the added confusion that introducing a new operator would cause. It should be possible to define a new operator, "=(point, point)" with the appropriate settings to make this work in your specific case. Such a setup ideally would be on the Wiki (and maybe one is...haven't looked) for others to references. A PGXN extension would also be a good choice for distribution. It doesn't seem easy or important enough to add to core. David J.
