Hi Gioele,

Queries with positional predicates such as the one that I posted in my last mail (in private, attached below) are now optimized as well.

Best, Christian

[1] http://files.basex.org/releases/latest/

On Mon, Jun 15, 2015 at 1:09 PM, Christian Grün christian.gruen@gmail.com wrote:

Hi Gioele,

...

I had a look at the info view but I fail to understand whether it is optimized or not. What should I look at? Sometimes I see a "Optimized Query" section, but it is not present for these two queries.

I see. Yes, this means that the query is not rewritten. Instead, this is one is optimized for index access, as the query info (and, obviously, in this case the execution time) will show you:

/descendant::tei:orth[text() = "arci"]

I noticed that the query is not rewritten because of the positional predicate (which are generally brain twisters in XQuery). Things look better with the following query (but it may yield other results):

/descendant::tei:orth [text() = "arci"] [ancestor-or-self::* [@xml:lang][starts-with(@xml:lang, "san")] ] /parent::tei:form/parent::*[self::tei:entry or self::tei:re]

The following query should take advantage of the index:

for $n in /descendant::tei:orth[text() = "arci"] where $n/ancestor-or-self::* [@xml:lang][1][starts-with(@xml:lang, "san")] return $n/parent::tei:form/parent::* [self::tei:entry or self::tei:re]

Best, Christian