lucene-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Robert Muir <rcm...@gmail.com>
Subject Re: inconsistency/performance trap of empty terms
Date Fri, 29 Oct 2010 00:49:55 GMT
On Thu, Oct 28, 2010 at 8:35 PM,  <karl.wright@nokia.com> wrote:
> In database queries, it is often useful to treat an empty value specially, and be able
to search explicitly for records that have (for instance) no field X, or no value for field
X.  I can't regurgitate offhand all the precise situations that I've used this and claim
that they would apply to a search engine, but it is conceivable that it could be helpful to
somebody.  Would your proposed change preclude current or future support for such null queries?

in a database, not having a value for field X is 'null'.

1. null is different than empty term.
2. comparing this concept with an inverted index vs a database record
really isn't a comparison.

by not having 'empty' terms (terms of length=0), what searches would
be affected.

I still haven't heard a real use case (though surely perhaps there is
someone abusing this somehow), but there is a serious performance trap
that is definitely real.

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@lucene.apache.org
For additional commands, e-mail: dev-help@lucene.apache.org


Mime
View raw message