Thanks Shai. That all makes sense to me.
bq. Perhaps we should add to the javadocs something like "you can call
query.weight().scoresDocsOutOfOrder to instantiate the optimal TFC/TSDC"?
I guess this is all I would argue for as well - basically a bit more
informative javadoc for scoreOutOfOrder:
TopScoreDocCollector:
* Creates a new {...@link TopScoreDocCollector} given the number of hits to
* collect and whether documents are scored in order by the input
* {...@link Scorer} to {...@link #setScorer(Scorer)}.
Shai Erera wrote:
> I think we've had a similar discussion on this issue (as part of the
> JIRA issue), and the reason for not defaulting to anything was
> back-compat.
>
> For example, we know that not tracking doc scores is better when you
> simply sort by a field. But we can't have a default that says "don't
> track doc scores", since if people will use it - they might break. On
> the other hand, defaulting in 2.9 to track doc scores is not good
> either, because we want to stop tracking scores when you sort ...
>
> So the outcome was that the "easy" search methods on Searcher pick the
> best defaults for you (and we've documented that in 3.0 those methods
> will stop tracking scores etc.) and if you choose to instantiate your
> own TopFieldCollector, then you probably know what you're doing, and
> therefore defaults are not that important there.
>
> I guess back-compat wise we can say that in 2.9 there is a "create"
> method which picks certain defaults and will change in 3.0. But I
> think the bigger question is if someone instantiates TFC, does he do
> it because he wants to override Lucene's Searcher defaults? I guess
> the answer is not a definite YES (because I can think of cases where I
> instantiate TFC for other purposes than overriding Lucene's defaults),
> but is it perhaps MOST LIKELY?
>
> The one parameter which I think may confuse people is w/
> docsScoredInOrder - that is only relevant if I use my own Scorer,
> which I think is a very advanced thing. And if I need to instantiate
> TFC or TSDC, I may not know what to pass there ... But here there is
> no good default either, because it really depends on the query that is
> run. Perhaps we should add to the javadocs something like "you can
> call query.weight().scoresDocsOutOfOrder to instantiate the optimal
> TFC/TSDC"?
>
> Shai
>
> On Mon, Aug 24, 2009 at 5:40 PM, Mark Miller <[email protected]
> <mailto:[email protected]>> wrote:
>
> I was just going to add actually:
>
> Yes you can just use the other Searcher methods. Perhaps thats just
> fine. I don't think this a large issue.
>
> But you could also use void search(Weight weight, Filter filter,
> Collector collector).
>
> I've created my own TopDocs collectors for a handful of reasons in
> the past.
>
> So I don't think this is a huge deal, but if you used the TopDoc
> collectors in the past,
> you just had to pass sort/numDocs - now that they are deprecated,
> if you
> happened to be
> using it - you go over to the new classes (after finding the new
> static
> factories) and are likely not sure what options to pick. Why not allow
> the same
> params and pick defaults that always work? People that want to eek out
> speed can tweak the
> longer param list.
>
> I agree - its not a huge deal - I guess it is more advanced use -
> but it
> was much easier to follow
> and use with the deprecated versions. Its gotten quite a bit more
> confusing.
>
> I'd still want to be able to play around with Collectors without being
> an expert.
>
> Just an idea though - I don't think its 100% necessary. When I see
> advanced options that are more for optimization though,
> I like to have defaults so that I don't have to understand everything
> perfectly before I use it.
>
> - Mark
>
> Yonik Seeley wrote:
> > But creating the collector is expert use, right?
> > The normal use would be from Searcher:
> > TopDocs search(Query query, int n)
> > TopDocs search(Query query, Filter filter, int n)
> >
> >
> > -Yonik
> > http://www.lucidimagination.com
> >
> >
> >
> > On Mon, Aug 24, 2009 at 10:15 AM, Mark
> Miller<[email protected] <mailto:[email protected]>> wrote:
> >
> >> Hey all,
> >>
> >> Hits, which used to be the non expert search API has been
> deprecated -
> >> so TopDocs is now
> >> essentially the non expert search API. But when you go to use
> it you are
> >> greeted with:
> >>
> >> public static TopFieldCollector create(Sort sort, int numHits,
> >> boolean fillFields, boolean trackDocScores, boolean
> trackMaxScore,
> >> boolean docsScoredInOrder)
> >>
> >> and
> >>
> >> public static TopScoreDocCollector create(int numHits, boolean
> >> docsScoredInOrder) {
> >>
> >> if (docsScoredInOrder) {
> >> return new InOrderTopScoreDocCollector(numHits);
> >> } else {
> >> return new OutOfOrderTopScoreDocCollector(numHits);
> >> }
> >>
> >> }
> >>
> >> Woah ! Think of the poor noobies ;)
> >>
> >> I don't know if I want my docs scored in order. Seriously, I
> don't. Its
> >> sounds nice though. And fill fields? Please do I guess :)
> >>
> >> What do you think about having versions that default to something
> >> reasonable ? And you just have to give numhits and sort, numhits?
> >>
> >> This API now has a dual role IMO - expert and non expert.
> >>
> >> --
> >> - Mark
> >>
> >> http://www.lucidimagination.com
> >>
> >>
> >>
> >>
> >>
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> >>
> >
> >
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>
> --
> - Mark
>
> http://www.lucidimagination.com
>
>
>
>
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- Mark
http://www.lucidimagination.com
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