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From Michael McCandless <luc...@mikemccandless.com>
Subject Re: Faceting : what are the limitations of Taxonomy (Separate index and hierarchical facets) and SortedSetDocValuesFacetField ( flat facets and no sidecar index) ?
Date Wed, 16 Nov 2016 13:46:31 GMT
No, SSDVFF does not do hierarchical faceting today, but this is just a
limitation of the current implementation, and with some changes
(patches welcome!), it could do so.

Mike McCandless

http://blog.mikemccandless.com


On Mon, Nov 14, 2016 at 1:38 AM, Chitra R <chithu.r111@gmail.com> wrote:
>
>      Hey, thank you so much for the fast response, I agree NRT refresh is
> somewhat costly operations and this is the major pitfall, suppose we use doc
> value faceting.
>
>
>                  While indexing SortedSetDocValuesFacetField , it stores
> path and dimension of the given field internally. So Can we achieve
> hierarchical facets using DrillDownQuery? Hope, purpose of storing path and
> dimension is to achieve hierarchical facets. If yes (ie we can achieve
> hierarchy in SSDVFF) , so what is the need to move over taxonomy?
>  Else I missed anything?
>
>
>                  What is the real purpose to store path and dimension in
> SSDVF field?
>
>
> Kindly post your suggestions.
>
> Regards,
> Chitra
>
>
>
> On Sat, Nov 12, 2016 at 4:03 AM, Michael McCandless
> <lucene@mikemccandless.com> wrote:
>>
>> On Fri, Nov 11, 2016 at 5:21 AM, Chitra R <chithu.r111@gmail.com> wrote:
>>
>> >         i)Hope, when opening SortedSetDocValuesReaderState , we are
>> > calculating ordinals( this will be used to calculate facet count ) for
>> > doc
>> > values field and this only made the state instance somewhat costly.
>> >                       Am I right or any other reason behind that?
>>
>> That's correct.  It adds some latency to an NRT refresh, and some heap
>> used to hold the ordinal mappings.
>>
>> >          ii) During indexing, we are providing facet ordinals in each
>> > doc
>> > and I think it will be useful in search side, to calculate facet counts
>> > only for matching docs.  otherwise, it carries any other benefits?
>>
>> Well, compared to the taxonomy facets, SSDV facets don't require a
>> separate index.
>>
>> But they add latency/heap usage, and they cannot do hierarchical
>> facets yet (though this could be fixed if someone just built it).
>>
>> >          iii) Is SortedSetDocValuesReaderState thread-safe (ie) multiple
>> > threads can call this method concurrently?
>>
>> Yes.
>>
>> Mike McCandless
>>
>> http://blog.mikemccandless.com
>
>

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