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From Paolo Castagna <>
Subject Re: On SPARQL queries with ORDER BY + OFFSET + LIMIT
Date Fri, 02 Sep 2011 21:37:19 GMT
Paolo Castagna wrote:
> Hi,
> one thing which often people do/need is to paginate between results using
> OFFSET + LIMIT and when they do it they often ORDER BY something their
> results.
> I saw the "pseudo paging via query analysis of ORDER BY / OFFSET / LIMIT
> access patterns" idea in and it's great.
> Is there something we could do in ARQ (not caching) to optimize queries
> which have ORDER BY + OFFSET + LIMIT?

Maybe we can assume users will not hit 'next page' too many times.
Have you tried to see how many pages can you get from Google? :-)

We can increase the TOPN_LIMIT_THRESHOLD in TransformTopN to 100000 (?)
and apply the same TopN optimization we discussed in JENA-89 even when
In QueryIterTopN we simply return IteratorArray.create(y, offset, limit)
instead of IteratorArray.create(y).

What do you think?

If you like the idea, I'll create a JIRA for it and see if we can get
this done.


> If you have useful ideas, suggestions or interesting papers, please,
> point me at it.
> Thanks,
> Paolo

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