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From Erick Erickson <erickerick...@gmail.com>
Subject Re: Index time boosts, payloads, and long query strings
Date Sat, 21 Nov 2009 20:32:56 GMT
I'll take a whack at index .vs. query boosting. They are expressing very
different concepts. Let's claim we're interested in boosting the title
field....

Index time boosting is expressing "this document's title is X more important

than a normal document title". It doesn't matter *what* the title is,
any query that matches on anything in this document's title will give this
document a boost. I might use this to give preferential treatment to all
encyclopedia entries or something.

Query time boosting, like "title:solr^4.0" expresses "Any document with solr
in
it's title is more important than documents without solr in the title". This
really
only makes sense if you have other clauses that might cause a document
*without*
solr  the title to match......

Since they are doing different things, efficiency isn't really relevant.

HTH
Erick


On Sat, Nov 21, 2009 at 2:13 AM, Girish Redekar
<girish.redekar@aplopio.com>wrote:

> Hi ,
>
> I'm relatively new to Solr/Lucene, and am using Solr (and not lucene
> directly) primarily because I can use it without writing java code (rest of
> my project is python coded).
>
> My application has the following requirements:
> (a) ability to search over multiple fields, each with different weight
> (b) If possible, I'd like to have the ability to add extra/diminished
> weights to particular tokens within a field
> (c) My query strings have large lengths (50-100 words)
> (d) My index is 500K+  documents
>
> 1) The way to (a) is field boosting (right?). My question is: Is all field
> boosting done at query time? Even if I give index time boosts to fields? Is
> there a performance advantage in boosting fields at index time vs at using
> something like fieldname:querystring^boost.
> 2) From what I've read, it seems that I can do (b) using payloads. However,
> as this link (
>
> http://www.lucidimagination.com/blog/2009/08/05/getting-started-with-payloads/
> )
> suggests, I will have to write a payload aware Query Parser. Wanted to
> confirm if this is indeed the case - or is there a out-of-box way to
> implement payloads (am using Solr1.4)
> 3) For my project, the user fills multiple text boxes (for each query). I
> combine these into a single query (with different treatment for contents of
> each text box). Consequently, my query looks something like (fieldname1:
> queryterm1 queryterm2^2.0 queryterm3^3.0 +queryterm4)^1.0  Are there any
> guidelines for improving performance of such a system (sorry, this bit is
> vague)
>
> Any help with this will be great !
>
> Girish Redekar
> http://girishredekar.net
>

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