Chris Roffler <croffler@earthlink.net> writes: > I am trying to setup an index on an xpath expression but the query never > uses the index. > Could someone enlighten me please ?
> Here is the setup :
> CREATE INDEX xml_index > ON time_series > USING btree > ((xpath('/AttributeList/Attributes/Attribute/Name/text()'::text, > external_attributes)::text[]));
> And here is the query :
> select id, name > from > time_series > where > (xpath('/AttributeList/Attributes/Attribute/Name/text()', > external_attributes))[1]::text='Attribute100'
Doesn't work that way --- subscripting isn't an indexable operation. To make that query fast with a standard index, you'd need the index to be on