Yes, it is sad but true that multi-word synonym processing does not "work
right out of the box" for all common interesting cases, although it does do
semi-well for index-time processing, but even there, matching synonyms of
varying lengths within larger phrases will sometimes work but sometimes not
unless you all some amount of phrase slop.
The LucidWorks Search query parser does handle query-time synonyms
reasonably well, but using some complicated, ad hoc processing that is not
easy to replicate in your average application that doesn't have that extra,
proprietary "magic". If you want robust, query-time processing of synonyms
(which is a lot more flexible than index-time processing), you would need to
replicate some form of that logic.
A couple of months ago I did propose that we design and implement a set of
interfaces to support robust handling of multi-word synonyms at query time,
but there was... NO interest expressed by any developers. Since then, the
Lucene and Solr query parsers have diverged even further, making the support
for such an interface even more problematic - unless we just bite the bullet
and say that the Lucene query parser is a hopeless dinosaur and leave it
behind in the dust as a remnant of "the early days" of Lucene and Solr.
Also, the fact that we still have three distinct main Solr query parsers
(SolrQueryParser, a derivative of the classic Lucene query parser, dismax,
and edismax) still makes this task rather problematic, let alone the fact
that there are a number of other "niche" query parsers which could use
better synonym processing, make this a very daunting task. If we ever do
integrate the "big three" (and write the Lucene query parser), then maybe
the time will be ripe to revisit robust query-time multi-word synonym
support.
(Or, maybe LucidWorks will finally donate their query parser!)
-- Jack Krupansky
-----Original Message-----
From: Bernd Fehling
Sent: Thursday, November 29, 2012 8:19 AM
To: solr-user@lucene.apache.org
Subject: Re: Multi word synonyms
There are also other solutions:
Multi-word synonym filter (synonym expansion)
https://issues.apache.org/jira/browse/LUCENE-4499
Since Solr 3.4 i have my own solution which might be obsolete if
LUCENE-4499 will be in a released version.
http://www.ub.uni-bielefeld.de/~befehl/base/solr/eurovoc.html
Am 29.11.2012 13:44, schrieb O. Klein:
Found an article about the issue of multi word synonyms
<http://nolanlawson.com/2012/10/31/better-synonym-handling-in-solr/> .
Not sure it's the solution I'm looking for, but it may be for someone
else.
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