The external data is just an array of fixed-length records, one for each Lucene document. Indexes are updated at regular intervals in one jvm. A searcher jvm opens the index and reads all the fixed-length records into RAM. Given an index-wide docId, the custom scorer can quickly access the corresponding fixed-length external data.
Could you explain a bit more about how mapping the external data to be per segment would work? As I said, rebuilding the whole file isn't a big deal and the single file keeps the Searcher's use of it simple. With or without a SegmentReader->docBase map (which does sound like a huge performance hit), I still don't see how the custom scorer gets the segment number. Btw, the custom scorer usually becomes part of a ConjunctionScorer (if that matters) >FSHQ expects you to init it with the top-level reader, and then insert using top docIDs. For sorting, I'm using FSHQ directly with a custom collector that inserts docs to the FSHQ. But the custom collector is passed the segment-relative docId and the custom comparator needs the index-wide docId. The custom collector extends HitCollector. I'm missing where this type of collector finds the docBase. Thanks, Peter On Tue, Nov 17, 2009 at 5:49 AM, Michael McCandless < luc...@mikemccandless.com> wrote: > On Mon, Nov 16, 2009 at 6:38 PM, Peter Keegan <peterlkee...@gmail.com> > wrote: > > >>Can you remap your external data to be per segment? > > > > That would provide the tightest integration but would require a major > > redesign. Currently, the external data is in a single file created by > > reading a stored field after the Lucene index has been committed. > Creating > > this file is very fast with 2.9 (considering the cost of reading all > those > > stored fields). > > OK. Though if you update a few docs and open a new reader, you have > to fully recreate the file? (Or, your app may simply never need to do > that...). > > >>For your custom sort comparator, are you using FieldComparator? > > > > I'm using the deprecated FieldSortedHitQueue. I started looking into > > replacing it with FieldComparator, but it was much more involved than I > had > > expected, so I postponed. Also, this would only be a partial solution to > a > > query with a custom scorer and custom sorter. > > You are using FSHQ directly, yourself? (Ie, not via TopFieldDocCollector)? > > FSHQ expects you to init it with the top-level reader, and then insert > using top docIDs. > > >>Failing these, Lucene currently visits the readers in index order. > >>So, you could accumulate the docBase by adding up the reader.maxDoc() > >>for each reader you've seen. However, this may change in future > >>Lucene releases. > > > > This would work for the Scorer but not the Sorter, right? > > I don't fully understand the question -- the sorter is simply a > Collector impl, and Collector.setNextReader tells you docBase when a > the search advances to the next reader. > > >>You could also, externally, build your own map from SegmentReader -> > >>docBase, by calling IndexReader.getSequentialSubReaders() and stepping > >>through adding up the maxDoc. Then, in your search, you can lookup > >>the SegmentReader you're working on to get the docBase? > > > > I think this would work for both Scorer and Sorter, right? > > This seems like the best solution right now. > > This is a generic solution, but just make sure you don't do the > map lookup for every doc collected, if you can help it, else that'll > slow down your search. > > Mike > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org > >
