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From Trejkaz <trej...@trypticon.org>
Subject Re: Merging results from two searches on two separate Searchers
Date Wed, 15 Feb 2012 00:56:58 GMT
On Wed, Feb 15, 2012 at 11:46 AM, Uwe Schindler <uwe@thetaphi.de> wrote:
> Scores are only compatible if the query is the same, which is not the case for you.
> So you cannot merge hits from different queries.

So I guess in the case where the different query parsers happen to
generate the same query, it's safe to do then. This is actually much
better than I was expecting. :)

Which leaves the (hopefully rarer) case of them generating
actually-different queries.

I assume the cause for the incompatibility is something like this:

  User's query: "cats"
  Suppose query parser 1 converts to "text:cats"
  Suppose query parser 2 converts to "text:cat"

Because query parser 2 is converting "cat" -> "cat" as well as "cats"
-> "cat", this affects the doc frequency of "cat", which as a result
affects the score.

But of course we want all the results in one list at the end, so we
have to merge it *somehow*. So I was wondering that if the score by
itself is not enough, maybe there is some way to weight it so that it
can be merged again.

TX

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