Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> writes:
> Seamus Abshere wrote:
>> I created an index with text_pattern_ops because I want fast prefix search [1] [2].
>> ...but I don't think it's working when I use a column reference || '%'...
> An index can only be used for expressions like
> <indexed expression> <operator from the opclass> <constant>
> and you have a column refrence on the right side.
"constant" is a bit too strong here, but it definitely can't be
"expression using another column from the same table". It has to
be an expression that will hold stable throughout a scan of the
table you wish to index.
regards, tom lane