All This is a gentle reminder to say please be patient when posting to any Apache mailing lists (including this one)
People are spread geographically across a wide variety of time zones and the person capable of answering your question may not see it for some time as it may be sent well outside their normal waking/working hours. Everyone who responds on this mailing list is working as a volunteer donating their time so please don't abuse this - Re-posting the same question only a few hours later only serves to annoy people Rob On 10/03/2015 09:55, "Rose Beck" <[email protected]> wrote: >Sorry for yet another mail. Is there some document from which I can >understand how ORDER BY and LIMIT clause are evaluated by Jena. I read >the documentation here: >http://jena.apache.org/documentation/query/arq-query-eval.html but I >am not able to understand the solution from it. > >On Tue, Mar 10, 2015 at 11:24 AM, Rose Beck <[email protected]> wrote: >> Hi, >> >> I saw the following issue posted on Jena website (which has been >> recently resolved): >> Avoid a total sort for ORDER BY + LIMIT queries >> (https://issues.apache.org/jira/browse/JENA-89). >> >> I am very interested in understanding as to how does Jena-ARQ avoids >> total sort for ORDER BY + LIMIT queries. In the post it is mentioned >> that Jena-ARQ uses priority queue for avoiding a final sort, however >> it is also mentioned that "ARQ's algebra package contains already a >> OpTopN [3] operator. The OpExecutor [4] will need to use a new >> QueryIterTopN instead of QueryIterSort + QueryIterSlice." It is not >> clear now does the priority queue benefit from OpTopN operator and >> QueryIterTopN as the links [3] and [4] mentioned on the website does >> not work, so I am not able to understand their operation and as to how >> do they help in avoiding a total sort. >> >> Can someone please explain how does Jena-ARQ execute the queries >> containing ORDER BY + LIMIT clause. >> >> With Warm Regards, >> Rose > > > >-- >With Warm Regards, >Rose
