Grant Ingersoll <[EMAIL PROTECTED]> wrote on 28/05/2006 06:22:06 PM:

> I have added http://wiki.apache.org/jakarta-lucene/LucenePlanning to the
> Wiki.  Currently there are two items of interest in it.  A start of some
> documentation related to a Java 1.5 migration and a start of some
> documentation concerning how to add more flexible indexing options and
> how to store metadata at the index level.  The former conversation was
> started by Karl on the developer's list and the latter was kicked off by
> an email from me to Doug on how to implement #11 of
> http://wiki.apache.org/jakarta-lucene/Lucene2Whiteboard

I think the suggestion for position-specific boost is not enough,
and what is really be needed is a more general "payload" mechanism,
that allows storing with each position a variable length payload
(byte[]) which the application can use for its purposes. Such payloads
are essential for many applications - including XML search, faceted
search (if you don't want to cache stuff in memory, like people
suggested on a thread from last week), fast numeric search, and more.

Adding payloads is actually not difficult, but would require a change
to the index file format (probably the positions file) and some
changes to the basic indexing API (such as a new Field constructor
with a payload, adding payloads to tokens coming out of an analyzer,
and getting payloads from a TermPositions), so we better do this
after a bit of thought, and do it now - when it's natural to
start thinking about changes to the index file format.

Another, related, improvement, I think, should be to make positions
optional for certain fields. For some fields, positions are useless
because phrase search will never be used. For example, a field that
keeps a list of "categories" that a document is in. A document can
either be, or not be, in a category, but there is no significance
in the order of these categories in a document's list.


--
Nadav Har'El


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