David Morgenstern <d.morgenstern@xxxxxxxxxxx> writes: > Can somebody explain why text_pattern_ops can be used on varchar > columns, considering it can’t be used for bpchar columns? The underlying rule there is that an opclass can be applied to an index column if the column's actual type is binary-coercible to what the opclass expects. varchar is binary-coercible to text, since they're basically the same type. bpchar is not, because we must insert a coercion function that strips any trailing blanks. (Essentially, the restriction exists because the index machinery won't cope with such intermediate functions.) regards, tom lane
