On 21/01/2020 20:37, Élie Roux wrote:
which I believe might result in a penalty... although frankly, I still
can't understand how a very basic bgp like
21 (bgp
22 (triple bdr:G844 ?rel ?res)
23 (triple ?res rdf:type :Place)
24 (triple ?res skos:prefLabel ?reso)
can take 100ms. Is there a way to tune the optimization level of
features in queries or at the Fuseki level?
As Lorenz says, do you have a stats.opt file?
A possible explanation is that you might be using fixed.opt instead of
stats.opt (or have some really out of date stats file).
With fixed.opt the optimizer will reorder based on the more grounded
triples. In your case this is the second pattern in that block:
(triple ?res rdf:type :Place)
If there are a lot of :Places compared to properties of your particular
place bdr:G844 then this isn't optimal.
Apart from using stats.opt, with the option to manually tune the rules,
you have the option to use none.opt to stop any reordering of triple
patterns in bgps. That allows you to write the triple patterns in
optimal order for your data (which you have in this case).
Dave
