But couldn't the IDF problem be fixed by applying the same IDF to all synonyms, e.g. via DisjunctionMaxQuery? (Maybe the ideal would be an average, not a max.)
(E)dismax applies this query per-field, but AFAICT there is nothing stopping anybody (modulo query parser construction :) ) from using it on synonyms in the same field. Steve On Dec 12, 2012, at 12:50 PM, Walter Underwood <wun...@wunderwood.org> wrote: > Query parsers cannot fix the IDF problem or make query-time synonyms faster. > Query synonym expansion makes more search terms. More search terms are more > work at query time. > > The IDF problem is real; I've run up against it. The most rare variant of the > synonym have the highest score. This probably the opposite of what you want. > For me, it was "TV" and "television". Documents with "TV" had higher scores > than those with "television". > > wunder > > On Dec 12, 2012, at 9:45 AM, Roman Chyla wrote: > >> @wunder >> It is a misconception (well, supported by that wiki description) that the >> query time synonym filter have these problems. It is actually the default >> parser, that is causing these problems. Look at this if you still think >> that index time synonyms are cure for all: >> https://issues.apache.org/jira/browse/LUCENE-4499 >> >> @joe >> If you can use the flexible query parser (as linked in by @Swati) then all >> you need to do is to define a different field with a different tokenizer >> chain and then swap the field names before the analyzers processes the >> document (and then rewrite the field name back - for example, we have >> fields called "author" and "author_nosyn") >> >> roman >> >> On Wed, Dec 12, 2012 at 12:38 PM, Walter Underwood >> <wun...@wunderwood.org>wrote: >> >>> Query time synonyms have known problems. They are slower, cause incorrect >>> IDF, and don't work for phrase synonyms. >>> >>> Apply synonyms at index time and you will have none of those problems. >>> >>> See: >>> http://wiki.apache.org/solr/AnalyzersTokenizersTokenFilters#solr.SynonymFilterFactory >>> >>> wunder >>> >>> On Dec 12, 2012, at 9:34 AM, Swati Swoboda wrote: >>> >>>> Query-time analyzers are still applied, even if you include a string in >>> quotes. Would you expect "foo" to not match "Foo" just because it's >>> enclosed in quotes? >>>> >>>> Also look at this, someone who had similar requirements: >>>> >>> http://lucene.472066.n3.nabble.com/Synonym-Filter-disable-at-query-time-td2919876.html >>>> >>>> >>>> -----Original Message----- >>>> From: joe.cohe...@gmail.com [mailto:joe.cohe...@gmail.com] >>>> Sent: Wednesday, December 12, 2012 12:09 PM >>>> To: solr-user@lucene.apache.org >>>> Subject: Re: Can a field with defined synonym be searched without the >>> synonym? >>>> >>>> >>>> I'm aplying only query-time synonym, so I have the original values >>> stored and indexed. >>>> I would've expected that if I search a strin with quotations, i'll get >>> the exact match, without applying a synonym. >>>> >>>> any way to achieve that? >>>> >>>> >>>> Upayavira wrote >>>>> You can only search against terms that are stored in your index. If >>>>> you have applied index time synonyms, you can't remove them at query >>> time. >>>>> >>>>> You can, however, use copyField to clone an incoming field to another >>>>> field that doesn't use synonyms, and search against that field instead. >>>>> >>>>> Upayavira >>>>> >>>>> On Wed, Dec 12, 2012, at 04:26 PM, >>>> >>>>> joe.cohen.m@ >>>> >>>>> wrote: >>>>>> Hi >>>>>> I hava a field type without defined synonym.txt which retrieves both >>>>>> records with "home" and "house" when I search either one of them. >>>>>> >>>>>> I want to be able to search this field on the specific value that I >>>>>> enter, without the synonym filter. >>>>>> >>>>>> is it possible? >>>>>> >>>>>> thanks. >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> View this message in context: >>>>>> http://lucene.472066.n3.nabble.com/Can-a-field-with-defined-synonym-b >>>>>> e-searched-without-the-synonym-tp4026381.html >>>>>> Sent from the Solr - User mailing list archive at Nabble.com. >>>> >>>> >>>> >>>> >>>> >>>> -- >>>> View this message in context: >>> http://lucene.472066.n3.nabble.com/Can-a-field-with-defined-synonym-be-searched-without-the-synonym-tp4026381p4026405.html >>>> Sent from the Solr - User mailing list archive at Nabble.com. >>> >>> -- >>> Walter Underwood >>> wun...@wunderwood.org >>> >>> >>> >>> > > -- > Walter Underwood > wun...@wunderwood.org > > >
