Silvio Matthes <silvio(dot)matthes(at)xcom(dot)de> writes:
> I try to select the rows of a table where the content of a varchar-column
> is empty ('') and PostgresQL is doing a seqscan.
If there are a very large number of rows with param_value='', it's
entirely possible that using an index to find them is counterproductive.
regards, tom lane