About clear(Object sentinel) - is it still a question
no, it is not. Makes no sense with mutable elements :)
----- Original Message ----
> From: Shai Erera <ser...@gmail.com>
> To: java-user@lucene.apache.org
> Sent: Wednesday, 30 September, 2009 21:02:19
> Subject: Re: TSDC, TopFieldCollector & co
>
> I was half way through answering the second part when I noticed your second
> update :).
>
> I don't know about adding reset() to Collector. It makes sense "for
> completeness" in case other Collectors can be reset() as well. But reset()
> is a delicate method. It needs to be used cautiously. E.g., if you ask for
> 100 results, and then want to ask for just 10/20/40, a user might be tempted
> to think he can call reset() and it will work. But reset() can be called
> only if you want to ask for 100 results again, at least if we don't want to
> complicate anything in the code. That's why I think it better exist on TSDC
> w/ the proper documentation. If anything, reset() is a TSDC-related
> operation (or TopDocsCollector). If I have my own Collector, its reset()
> method signature might need to be different, not to speak about
> documentation.
>
> About clear(Object sentinel) - is it still a question (now that you
> understood getSentinelValue())? I think we should not make it final anyway.
> It restricts PQ extensions unnecessarily ...
>
> Shai
>
> On Wed, Sep 30, 2009 at 8:41 PM, eks dev wrote:
>
> > > BTW eks, you asked about reusing TSDC.
> >
> > yeah, it is normally not a big deal to allocate everything again, but these
> > arrays are not necessarily small, I guess it would make sense to open this
> > possibility.
> >
> > do you think where would be better to add reset(), TSDC or to Collector?
> >
> > I would even suggest to change clear method to become clear(Object
> > sentinel) to PQ instead... or to add such a method (backwards compatibility)
> > ...
> >
> > Another question:
> > Looking at the code in PQ, it was not really clear to me why sentinels have
> > to be allocated maxSize times in initialize method? I am talking about:
> >
> > // If sentinel objects are supported, populate the queue with them
> > Object sentinel = getSentinelObject();
> > if (sentinel != null) {
> > heap[1] = sentinel;
> > for (int i = 2; i < heap.length; i++) {
> > heap[i] = getSentinelObject(); //Why not simply heap[i] = sentinel;
> > }
> > size = maxSize;
> > }
> >
> > getSentinelObject() creates new object every time (HitQueue)
> >
> > are these objects mutable?
> >
> >
> >
> >
> >
> >
> >
> > ----- Original Message ----
> > > From: Shai Erera
> > > To: java-user@lucene.apache.org
> > > Sent: Wednesday, 30 September, 2009 18:11:03
> > > Subject: Re: TSDC, TopFieldCollector & co
> > >
> > > BTW eks, you asked about reusing TSDC. PQ has a clear() method, so it can
> > be
> > > reused. Only currently it's final and nullifies the array. We'll need to
> > > un-final it, and then override in HitQueue to just reset the ScoreDoc
> > > instances to be sentinels again. And of course add a reset() method to
> > TSDC.
> > >
> > > On Wed, Sep 30, 2009 at 5:26 PM, eks dev wrote:
> > >
> > > > Thanks Mark, Shai,
> > > > I was getting confused by so many possibilities to do the "almost the
> > same
> > > > thing" ;)
> > > >
> > > > But have figured it out by peeking into BoolenQuery code that decides
> > if
> > > > "out of order" should be used..., BQ will pick the right TSDC ... I
> > like it,
> > > > option 1 it is minimum user code.
> > > >
> > > > Cheers, eks
> > > >
> > > >
> > > >
> > > > ----- Original Message ----
> > > > > From: Shai Erera
> > > > > To: java-user@lucene.apache.org
> > > > > Sent: Wednesday, 30 September, 2009 17:12:38
> > > > > Subject: Re: TSDC, TopFieldCollector & co
> > > > >
> > > > > I agree. If you need sort-by-score, it's better to use the "fast"
> > search
> > > > > methods. IndexSearcher will create the appropriate TSDC instance for
> > you,
> > > > > based on the Query that was passed.
> > > > >
> > > > > If you need to create multiple Collectors and pass a kind of
> > > > Multi-Collector
> > > > > to IndexSearcher, then you should create TSDC according to Mark's
> > example
> > > > > above.
> > > > >
> > > > > Shai
> > > > >
> > > > > On Wed, Sep 30, 2009 at 4:57 PM, Mark Miller wrote:
> > > > >
> > > > > > If you want relevance sorting (Sort.Score not Sort.Relevance
> > right?),
> > > > > > I'd think you want to use TopScoreDocCollector, not
> > TopFieldCollector.
> > > > > > The only reason to use relevance with TopFieldCollector is if you
> > you
> > > > > > are doing a nth sort with a field sort as well.
> > > > > >
> > > > > > You don't really need to worry about things like turning off the
> > max
> > > > > > score tracking here - its just going to be the first doc on the
> > queue.
> > > > > >
> > > > > > You also do want to specify whether or not to collect docs in order
> > if
> > > > > > you care about performance:
> > > > > >
> > > > > > public static TopScoreDocCollector create(int numHits, boolean
> > > > > > docsScoredInOrder)
> > > > > >
> > > > > > ie:
> > > > > >
> > > > > > TopScoreDocCollector.create(nDocs, !weight.scoresDocsOutOfOrder());
> > > > > >
> > > > > > Which means you just want option 1.
> > > > > >
> > > > > > --
> > > > > > - Mark
> > > > > >
> > > > > > http://www.lucidimagination.com
> > > > > >
> > > > > >
> > > > > >
> > > > > > eks dev wrote:
> > > > > > > Hi All,
> > > > > > >
> > > > > > > What is the best way to achieve the following and what are the
> > > > > > differences, if I say "I do not normalize scores, so I do not need
> > max
> > > > score
> > > > > > tracking, I do not care if hits are returned in doc id order, or
> > any
> > > > other
> > > > > > order. I need only to get maxDocs *best scoring* documents":
> > > > > > >
> > > > > > > OPTION 1:
> > > > > > > TopDocs top = ixSearcher.search(q, filter, maxDocs);
> > > > > > >
> > > > > > > OPTION 2:
> > > > > > > final TopScoreDocCollector tfc =
> > > > TopScoreDocCollector.create(maxDocs,
> > > > > > false);
> > > > > > > ixSearcher.search(q, filter, tfc);
> > > > > > > TopDocs top = tfc.topDocs();
> > > > > > >
> > > > > > >
> > > > > > > OPTION 3:
> > > > > > > final TopFieldCollector tfc =
> > > > > > TopFieldCollector.create(Sort.RELEVANCE, maxDocs,
> > > > > > > false /* fillFields */,
> > > > > > > true /* trackDocScores */,
> > > > > > > false /* trackMaxScore */,
> > > > > > > false /* docsInOrder */);
> > > > > > >
> > > > > > > ixSearcher.search(q.weight(ixSearcher),filter, tfc);
> > > > > > > TopDocs top = tfc.topDocs();
> > > > > > >
> > > > > > >
> > > > > > > what are the pros and cons?
> > > > > > > If I read javadoc correctly,
> > > > > > > - OPTION 1 tracks max score and delivers doc Ids in order
> > (suboptimal
> > > > > > performance for my case)
> > > > > > > - OPTION 2 I do not know abut max score tracking, but doc Ids are
> > not
> > > > > > required to be in order
> > > > > > > - OPTION 3 looks like exactly what I want, but one performance
> > > > comment in
> > > > > > javadoc about Sort.RELEVANCE made me think if that is the fastest
> > way?
> > > > > > >
> > > > > > > What would be recommended here, any other options to achieve the
> > > > fastest
> > > > > > search with above defined conditions (no max score tracking and doc
> > id
> > > > order
> > > > > > irrelevant)? OPTIN2 looks nice, but as said, I am not sure about
> > max
> > > > score
> > > > > > tracking?
> > > > > > >
> > > > > > > Thanks,
> > > > > > > eks
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > ---------------------------------------------------------------------
> > > > > > > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org
> > > > > > > For additional commands, e-mail:
> > java-user-h...@lucene.apache.org
> > > > > > >
> > > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > ---------------------------------------------------------------------
> > > > > > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org
> > > > > > For additional commands, e-mail: java-user-h...@lucene.apache.org
> > > > > >
> > > > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > ---------------------------------------------------------------------
> > > > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org
> > > > For additional commands, e-mail: java-user-h...@lucene.apache.org
> > > >
> > > >
> >
> >
> >
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org
> > For additional commands, e-mail: java-user-h...@lucene.apache.org
> >
> >
---------------------------------------------------------------------
To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org
For additional commands, e-mail: java-user-h...@lucene.apache.org
