Hi Grant, I'm hoping to check this out soon.
Thanks, Peter On 8/7/07, Grant Ingersoll <[EMAIL PROTECTED]> wrote: > > Hi Peter, > > Give https://issues.apache.org/jira/browse/LUCENE-975 a try. It > provides a TermVectorMapper that loads by position. > > Still not what ideally what you want, but I haven't had time to scope > that one out yet., > > -Grant > > On Jul 24, 2007, at 6:02 PM, Peter Keegan wrote: > > > Hi Grant, > > > > No problem - I know you are very busy. I just wanted to get a > > sense for the > > timing because I'd like to use this for a release this Fall. If I > > can get a > > prototype working in the coming weeks AND the performance is > > great :) , this > > would be terrific. If not, I'll have to fall back on a more complex > > design > > that handles the query outside of Lucene :( > > > > In the meantime, I'll try playing with LUCENE-868. > > > > Thanks for the update. > > Peter > > > > On 7/24/07, Grant Ingersoll <[EMAIL PROTECTED]> wrote: > >> > >> Sorry, Peter, I haven't had a chance to work on it. I don't see it > >> happening this week, but maybe next. > >> > >> I do think the Mapper approach via TermVectors will work. It will > >> require implementing a new mapper that orders by position, but I > >> don't think that is too hard. I started on one on the LUCENE-868 > >> patch (version 4) but it is not complete. Maybe you want to pick > >> it up? > >> > >> With this approach, you would iterate your spans, when you come to a > >> new doc, you would load the term vector using the PositionMapper, and > >> then you could index into the positions for the matches in the > >> document. > >> > >> I realize this does not cover the just wanting to get the Payload at > >> the match issue. Maybe next week... > >> > >> Cheers, > >> Grant > >> > >> On Jul 23, 2007, at 8:51 AM, Peter Keegan wrote: > >> > >> > Any idea on when this might be available (days, weeks...)? > >> > > >> > Peter > >> > > >> > On 7/16/07, Grant Ingersoll <[EMAIL PROTECTED]> wrote: > >> >> > >> >> > >> >> On Jul 16, 2007, at 1:06 AM, Chris Hostetter wrote: > >> >> > >> >> > > >> >> > : Do we have a best practice for going from, say a SpanQuery > >> doc/ > >> >> > : position information and retrieving the actual range of > >> >> positions of > >> >> > : content from the Document? Is it just to reanalyze the > >> Document > >> >> > : using the appropriate Analyzer and start recording once you > >> >> hit the > >> >> > : positions you are interested in? Seems like Term Vectors > >> >> _could_ > >> >> > : help, but even my new Mapper approach patch (LUCENE-868) > >> doesn't > >> >> > : really help, because they are stored in a term-centric > >> manner. I > >> >> > : guess what I am after is a position centric approach. That > >> >> is, give > >> >> > > >> >> > this is kind of what i was suggesting in the last message i sent > >> >> > to the java-user thread about paylods and SpanQueries (which i'm > >> >> > guessing is what prompted this thread as well)... > >> >> > > >> >> > http://www.nabble.com/Payloads-and-PhraseQuery- > >> >> > tf3988826.html#a11551628 > >> >> > >> >> > >> >> This is one use case, the other is related to the new patch I > >> >> submitted for LUCENE-960. In this case, I have a SpanQueryFilter > >> >> that identifies a bunch of docs and positions ahead of time. Then > >> >> the user enters new Span Query and I want to relate the matches > >> from > >> >> the user query with the positions of matches in the filter and > >> then > >> >> show that window. > >> >> > >> >> > > >> >> > my point was that currently, to retrieve a payload you need a > >> >> > TermPositions instance, which is designed for iterating in the > >> >> > order of... > >> >> > seek(term) > >> >> > skipTo(doc) > >> >> > nextPosition() > >> >> > getPayload() > >> >> > ...which is great for getting the payload of every instance > >> >> > (ie:position) of a specific term in a given document (or in > >> every > >> >> > document) but without serious changes to the Spans API, the > >> ideal > >> >> > payload > >> >> > API would let you say... > >> >> > skipTo(doc) > >> >> > advance(startPosition) > >> >> > getPayload() > >> >> > while (nextPosition() < endPosition) > >> >> > getPosition() > >> >> > > >> >> > but this seems like a nearly impossible API to implement > >> given the > >> >> > natore > >> >> > of hte inverted index and the fact that terms aren't ever > >> stored in > >> >> > position order. > >> >> > > >> >> > there's a lot i really don't know/understand about the lucene > >> term > >> >> > position internals ... but as i recall, the datastructure > >> written > >> >> > to disk > >> >> > isn't actually a tree structure inverted index, it's a long > >> >> > sequence of > >> >> > tuples correct? so in theory you could scan along the tuples > >> >> > untill you > >> >> > find the doc you are interested in, ignoring all of the term > >> info > >> >> > along > >> >> > the way, then whatever term you happen be on at the moment, you > >> >> > could scan > >> >> > along all of the positions until you find one in the range > >> you are > >> >> > interested in -- assuming you do, then you record the current > >> Term > >> >> > (and > >> >> > read your payload data if interested) > >> >> > >> >> I think the main issue I see is in both the payloads and the > >> matching > >> >> case above is that they require a document centric approach. And > >> >> then, for each Document, > >> >> you ideally want to be able to just index into an array so that > >> you > >> >> can go directly to the position that is needed based on > >> >> Span.getStart() > >> >> > >> >> > > >> >> > if i remember correctly, the first part of this is easy, and > >> >> > relative fast > >> >> > -- i think skipTo(doc) on a TermDoc or TermPositions will > >> happily > >> >> > scan for > >> >> > the first <term,doc> pair with the correct docId, > >> irregardless of > >> >> > the term > >> >> > ... the only thing i'm not sure about is how efficient it is to > >> >> > loop over > >> >> > nextPosition() for every term you find to see if any of them > >> are in > >> >> > your > >> >> > range ... the best case scenerio is that the first position > >> >> > returned is > >> >> > above the high end of your range, in which case you can stop > >> >> > immediately > >> >> > and seek to the next term -- butthe worst case is that you call > >> >> > nextPosition() over an over a lot of times before you get a > >> >> > position in > >> >> > (or above) your rnage .... an advancePosition(pos) that > >> wokred like > >> >> > seek > >> >> > or skipTo might be helpful here. > >> >> > > >> >> > : I feel like I am missing something obvious. I would > >> suspect the > >> >> > : highlighter needs to do this, but it seems to take the > >> reanalyze > >> >> > : approach as well (I admit, though, that I have little > >> experience > >> >> > with > >> >> > : the highlighter.) > >> >> > > >> >> > as i understand it the default case is to reanalyze, but if you > >> >> have > >> >> > TermFreqVector info stored with positions (ie: a > >> >> > TermPositionVector) then > >> >> > it can use that to construct a TokenStream by iterating over all > >> >> > terms and > >> >> > writing them into a big array in position order (see the > >> >> > TermSources class > >> >> > in the highlighter) > >> >> > >> >> > >> >> Ah, I see that now. Thanks. > >> >> > > >> >> > this makes sense when highlighting because it doesn't know what > >> >> > kind of > >> >> > fragmenter is going to be used so it needs the whole > >> TokenStream, > >> >> > but it > >> >> > seems less then ideal when you are only interested in a small > >> >> > number of > >> >> > position ranges that you know in advance. > >> >> > > >> >> > : I am wondering if it would be useful to have an alternative > >> Term > >> >> > : Vector storage mechanism that was position centric. > >> Because we > >> >> > : couldn't take advantage of the lexicographic compression, it > >> >> would > >> >> > : take up more disk space, but it would be a lot faster for > >> these > >> >> > kinds > >> >> > > >> >> > i'm not sure if it's really neccessary to store the data in a > >> >> position > >> >> > centric manner, assuming we have a way to "seek" by position > >> like i > >> >> > described above -- but then again i don't really know that > >> what i > >> >> > described above is all that possible/practical/performant. > >> >> > > >> >> > >> >> I suppose I could use my Mapper approach to organize things in a > >> >> position centric way now that I think about it more. Just > >> means some > >> >> unpacking and repacking. Still, probably would perform well > >> enough > >> >> since I can setup the correct structure on the fly. I will > >> give this > >> >> a try. Maybe even add a Mapper to do this. > >> >> > >> >> > >> >> -Grant > >> >> > >> >> > >> --------------------------------------------------------------------- > >> >> To unsubscribe, e-mail: [EMAIL PROTECTED] > >> >> For additional commands, e-mail: [EMAIL PROTECTED] > >> >> > >> >> > >> > >> ------------------------------------------------------ > >> Grant Ingersoll > >> http://www.grantingersoll.com/ > >> http://lucene.grantingersoll.com > >> http://www.paperoftheweek.com/ > >> > >> > >> > >> --------------------------------------------------------------------- > >> To unsubscribe, e-mail: [EMAIL PROTECTED] > >> For additional commands, e-mail: [EMAIL PROTECTED] > >> > >> > > -------------------------- > Grant Ingersoll > http://lucene.grantingersoll.com > > Lucene Helpful Hints: > http://wiki.apache.org/lucene-java/BasicsOfPerformance > http://wiki.apache.org/lucene-java/LuceneFAQ > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > >
