That's the idea that I tried to express. The point is that we need to tell the user that there is no need to worry about it, rather than that they're wrong to ask about it. Though we should probably actually just throw an error.Or maybe it should be the collation of the underlying table columns. Otherwise the collation returned by an index-only scan would be different from a table scan, no?
+1, dangerous -- Teodor Sigaev E-mail: teo...@sigaev.ru WWW: http://www.sigaev.ru/