Re: [basex-talk] Same query, huge difference in performance

Hi Paul,

//(sea|river|lake)

Due to the (somewhat peculiar) semantics of XPath, this path is identical to...

/descendant-or-self::node()/ (child::sea | child::river | child::lake)

...and it creates a massive amount of intermediate results. You could try to rewrite it to...

/descendant::sea | /descendant::river | /descendant::lake

...or...

/descendant::*[local-name() = ('sea', 'river', 'lake')]

...and I will try to tweak our optimizer to automatically do this for you in future (it already works for single steps).

Christian