Hi,
So I am working on a performance issue with our Triple Store (which is
based on HBase)
To give a background, the query I am executing looks like:
SELECT ?s
> WHERE {
> ?s a file:File .
> ?s ex:modified ?modified .
> FILTER(?modified >="2017-11-05T00:00:00.00000"^^<http://
> www.w3.org/2001/XMLSchema#dateTime>)
> }
Looking at the ARQ Execution plan, it is like this:
(slice 0 1000
> (project (?s)
> (filter (>= ?modified "2017-1105T00:00:00.00000"^^<http://
> www.w3.org/2001/XMLSchema#dateTime>)
> (bgp
> (triple ?s <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <
> http://www.example.com/File#File>)
> (triple ?s <http://www.example.com/common#modified> ?modified)
> ))))
AND I have around 45000 File Objects in my Triple Store.
As you can see from the above execution plan, I first get the Subject ID
for these 45000 File objects and then I fire a query per File Id to get the
odified date for the same. This clearly is not performant.
My Questions:
1. Is there a better way to create a SELECT query to have a good execution
plan.
2. If not, then can I somehow change the generation of execution plan?
3. Is it advisable to re-write the ARQ Execution Plan to suite our need and
how complicated this might be.
Thanks and please let me know if you need more information.
Thanks,
Anuj Kumar
--
*Anuj Kumar*
