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Re: Querying wildcard

Subject: Re: Querying wildcard
From: Anshum
Date: Thu, 30 Oct 2008 14:53:50 +0530
Hi Aditi,
In that case I could suggest you to just index the domain name seperately as
well i.e. index the following fields : email adddess, domain name; instead
of just email address.
When I said reverse the tokens, you could reverse the tokens while
indexing(just flipping the text string while indexing) and search for
reverse string while searching.
Eric might have a better solution though ! :)
Let me know if that solves the issue.
--
Anshum Gupta
Naukri Labs!
http://ai-cafe.blogspot.com

The facts expressed here belong to everybody, the opinions to me. The
distinction is yours to draw............


On Thu, Oct 30, 2008 at 12:13 PM, Aditi Goyal <aditigupta20@xxxxxxxxx>wrote:

> Thanks Anshum and Eric.
>
> Well, I was looking for something like searching by domain name in the
> email
> address etc.
> How can I reverse the tokens? Can you please explain in little detail?
>
> Thanks,
> Aditi
>
> On Thu, Oct 30, 2008 at 10:58 AM, Anshum <anshumg@xxxxxxxxx> wrote:
>
> > Hi Aditi,
> > As Eric mentioned, we'd need to know more to provide a rather apt
> solution.
> > At the same time, a prefix wildcard is a highly unoptimized thing for
> > lucene
> > because of the way the index is stored/read. Ideally you'd atleast want
> to
> > reverse the tokens as already mentioned.
> > This is because the index terms are lexically sorted while storing and so
> > the seem/fetch is efficient under normal cases(and not under the case of
> a
> > prefix wildcard).
> >
> > --
> > Anshum Gupta
> > Naukri Labs!
> > http://ai-cafe.blogspot.com
> >
> > The facts expressed here belong to everybody, the opinions to me. The
> > distinction is yours to draw............
> >
> >
> > On Wed, Oct 29, 2008 at 6:04 PM, Erick Erickson <erickerickson@xxxxxxxxx
> > >wrote:
> >
> > > Sure, there are many tricks. If you search the mail archives you'll
> > > find a bunch of them.
> > >
> > > One would be to reverse the tokens and make your leading
> > > wildcard queries into trailing ones on the reversed field.
> > >
> > > But without more details about what you're trying to accomplish,
> > > there's not much really useful advice we can offer.
> > >
> > > Best
> > > Erick
> > >
> > > On Wed, Oct 29, 2008 at 7:15 AM, Aditi Goyal <aditigupta20@xxxxxxxxx>
> > > wrote:
> > >
> > > > Hi All,
> > > >
> > > > I have been wanting to do a wildcard search with * as a first letter
> on
> > > an
> > > > index.
> > > > Is there a way out except for setAllowLeadingWildcard() of
> QueryParser
> > to
> > > > true? Because, i have heard it is an expensive operation.
> > > >
> > > > Thanks
> > > > Aditi
> > > >
> > >
> >
>
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