lucene-solr-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Erick Erickson <>
Subject Re: Solr/Lucene Faceted Search Too Many Unique Values?
Date Thu, 23 Jan 2014 01:39:00 GMT
A legitimate question that only you can answer is
"what's the value of faceting on fields with so many unique values?"

Consider the ridiculous case of faceting on <uniqueKey>. There's
almost exactly zero value in faceting on it, since all counts will be 1.

By analogy, with millions of tag values, will there ever be more than a very
small count of for any facet? And will showing those be useful to the

They may be, and Yago has a use-case where the answer is "yes". Before
trying to make Solr perform in this insance, though, I'd review the use-case
to see if it makes sense....


On Wed, Jan 22, 2014 at 5:09 PM, Yago Riveiro <> wrote:
> You will need to use DocValues if you want to use facets with this amount of terms and
not blow the heap.
> I have facets with ~39M of unique terms, the response time is about 10 ~ 40 seconds,
in my case is not a problem.
> --
> Yago Riveiro
> Sent with Sparrow (
> On Wednesday, January 22, 2014 at 10:59 PM, Bing Hua wrote:
>> Hi,
>> I am going to evaluate some Lucene/Solr capabilities on handling faceted
>> queries, in particular, with a single facet field that contains large number
>> (say up to 1 million) of distinct values. Does anyone have some experience
>> on how lucene performs in this scenario?
>> e.g.
>> Doc1 has tags A B C D ....
>> Doc2 has tags B C D E ....
>> etc etc millions of docs and there can be millions of distinct tag values.
>> Thanks
>> --
>> View this message in context:
>> Sent from the Solr - User mailing list archive at (

View raw message