[Xapian-discuss] Clarification of values, data, fields, and prefixed terms

[James Aylett]

On Tue, Sep 04, 2007 at 01:15:03AM -0400, Deron Meranda wrote:

> But I don't understand the performance arguments.  Even if looking up
> one value on a document means that all the values are retrieved,
> how is that different from fields inside the data part.  Doesn't it also
> have to retrieve all the fields from the data just to get to one of them
> as well?

Yes, but you aren't doing that in the match process. You might do it
for 100 documents, not several million that are checked during a
search - if you store data in the values, then every document
considered by the matcher is going to have that data pulled out (if
you use any values at all).

Does that help?

J

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  James Aylett                                                  xapian.org
  james at tartarus.org                               uncertaintydivision.org