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Posted to solr-user@lucene.apache.org by Chris Hostetter <ho...@fucit.org> on 2011/09/02 01:20:22 UTC

Re: can i create filters of score range

: so coming back to the issue .. even if am sorting it by _docid_ i need to do
: paging( 2 million docs in result)
: how is it internally doing it ?
: when sorted by docid, don we have deep pagin issue ? (getting all the
: previous pages into memory to get the next page)
: so whats the main difference we are gaining by sorting lucene docids and
: normal fields ?

when you sort on score (or some field) and ask for rows N - M, Lucene has 
to "collect" a priority queue of all the first" M docs in order to give 
you back N-M.  This is where the "deep paging" issue can use up a lot of 
memory.

I *think* that when you sort or _docid_ the Sort code doesn't build up a 
priority queue of all M docs, it just knows it should ignore the first N 
docs it sees and start keping track of them after N until it finds a total 
of M-N.

But like i said before...

: > >> *sort* on _docid_ asc, which should make all inherient issues with deep
: > >> paging go away (as far as i know).  At no point with the internal lucene

..."as far as i know" this should work, but i'm not certain.  there may be 
other issues. (or i may be smocking crack that the sorting code works this 
way)


-Hoss