you could always define 1 dynamicfield and encode the hierarchy level in the
fieldname:
<dynamicField name="_loc_hier_*" type="string" stored="false" indexed="true"
omitNorms="true"/>
using:
&facet=on&facet.field={!key=Location}_loc_hier_city&fq=_loc_hier_country:<somecountryid>
...
adding cityarea later for instance would be as simple as:
&facet=on&facet.field={!key=Location}_loc_hier_cityarea&fq=_loc_hier_city:<somecityid>
Cheers,
Geert-Jan
2010/3/3 Andy <angelf...@yahoo.com>
> Thanks. I didn't know about the {!key=Location} trick.
>
> Thanks everyone for your help. From what I could gather, there're 3
> approaches:
>
> 1) SOLR-64
> Pros:
> - can have arbitrary levels of hierarchy without modifying schema
> Cons:
> - each combination of all the levels in the hierarchy will result in a
> separate filter cache. This number could be huge, which would lead to poor
> performance
>
> 2) SOLR-792
> Pros:
> - each level of the hierarchy separately results in filter cache. Much
> smaller number of filter cache. Better performance.
> Cons:
> - Only 2 levels are supported
>
> 3) Separate fields for each hierarchy levels
> Pros:
> - same as SOLR-792. Good performance
> Cons:
> - can only handle a fixed number of levels in the hierarchy. Adding any
> levels beyond that requires schema modification
>
> Does that sound right?
>
> Option 3 is probably the best match for my use case. Is there any trick to
> make it able to deal with arbitrary number of levels?
>
> Thanks.
>
> --- On Tue, 3/2/10, Geert-Jan Brits <gbr...@gmail.com> wrote:
>
> From: Geert-Jan Brits <gbr...@gmail.com>
> Subject: Re: Implementing hierarchical facet
> To: solr-user@lucene.apache.org
> Date: Tuesday, March 2, 2010, 8:02 PM
>
> Using Solr 1.4: even less changes to the frontend:
>
> &facet=on&facet.field={!key=Location}countryid
> ...
> &facet=on&facet.field={!key=Location}cityid&fq=countryid:<somecountryid>
> etc.
>
> will consistently render the resulting facet under the name "Location" .
>
>
> 2010/3/3 Geert-Jan Brits <gbr...@gmail.com>
>
> > If it's a requirement to let Solr handle the facet-hierarchy please
> > disregard this post, but
> > an alternative would be to have your App control when to ask for which
> > 'facet-level' (e.g: country, state, city) in the hierarchy.
> >
> > as follows,
> >
> > each doc has 3 seperate fields (indexed=true, stored=false):
> > - countryid
> > - stateid
> > - cityid
> >
> > facet on country:
> > &facet=on&facet.field=countryid
> >
> > facet on state ( country selected. functionally you probably don't want
> to
> > show states without the user having selected a country anyway)
> > &facet=on&facet.field=countryid&fq=countryid:<somecountryid>
> >
> > facet on city (state selected, same functional analogy as above)
> > &facet=on&facet.field=cityid&fq=stateid:<somestateid>
> >
> > or
> >
> > facet on city (countryselected, same functional analogy as above)
> > &facet=on&facet.field=cityid&fq=countryid:<somecountryid>
> >
> > grab the resulting facat and drop it under "Location"
> >
> > pros:
> > - reusing fq's (good performance, I've never used hierarchical facets,
> but
> > would be surprised if it has a (major) speed increase to this method)
> > - flexible (you get multiple hierarchies: country --> state --> city and
> > country --> city)
> >
> > cons:
> > - a little more application logic
> >
> > Hope that helps,
> > Geert-Jan
> >
> >
> >
> >
> >
> > 2010/3/2 Andy <angelf...@yahoo.com>
> >
> > I read that a simple way to implement hierarchical facet is to
> concatenate
> >> strings with a separator. Something like "level1>level2>level3" with ">"
> as
> >> the separator.
> >>
> >> A problem with this approach is that the number of facet values will
> >> greatly increase.
> >>
> >> For example I have a facet "Location" with the hierarchy
> >> country>state>city. Using the above approach every single city will lead
> to
> >> a separate facet value. With tens of thousands of cities in the world
> the
> >> response from Solr will be huge. And then on the client side I'd have to
> >> loop through all the facet values and combine those with the same
> country
> >> into a single value.
> >>
> >> Ideally Solr would be "aware" of the hierarchy structure and send back
> >> responses accordingly. So at level 1 Solr will send back facet values
> based
> >> on country (100 or so values). Level 2 the facet values will be based on
> the
> >> states within the selected country (a few dozen values). Next level will
> be
> >> cities within that state. and so on.
> >>
> >> Is it possible to implement hierarchical facet this way using Solr?
> >>
> >>
> >>
> >>
> >
> >
> >
>
>
>
>
>
