Some day, I'd be interested to understand the "deeper question".
Here is a scenario to ponder about using different analyzers at index and query time.
Suppose you have a custom analyzer that places synonyms of words into the same token position as the original words. QueryParser does not deal with token position, neither does PhraseQuery currently. If you use the same analyzer for QueryParser, the query will be mangled. Using an analyzer that does everything the indexing analyzer does but without putting the synonyms into the token stream will do the trick (no need to look up synonyms at query time, they are already indexed anyway).
Also, if you use Field.Keyword at indexing time, perhaps having an analyzer at QueryParser time that does not "analyze" those keyword fields probably makes sense too.
Erik
-----Original Message----- From: Erik Hatcher [mailto:[EMAIL PROTECTED] Sent: Tuesday, January 13, 2004 3:19 AM To: Lucene Users List Subject: Re: Philosophy(??) question
On Jan 12, 2004, at 7:59 PM, Scott Smith wrote:I have some documents I'm indexing which have multiple languages in
them
(i.e., some fields in the document are always English; other fields
may be
other languages). Now, I understand why a query against a certain
field
must use the same analyzer as was used when that field was indexed
(stemming, stop words, etc.). It seems like different fields could use
different analyzers and the world would still be a happy place.
However,
since the analyzer() is passed in as part of the IndexWriter, that
can't
happen. Is there a way to do this (other than having multiple indexes
which
is a problem trying to do combined searches)? Or am I missing
something
more subtle? Sorry if I'm plowing old ground.
The new PerFieldAnalyzerWrapper (in v. 1.3) allows you to specify different analyzers, as its name says, per field. You simply specify which analyzer to use as a default and then any special ones for individual fields.
As for using the same analyzer for querying as for indexing - that is a deeper question that I've yet to agree with. There are some interesting reasons why you may want a different one - although they must "cooperate" in some fashion.
Erik
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