Hi Yonik,
Thanks for your answer!
I'm not quite I understood everything...please, see my comments below.
On Wed, Oct 19, 2016 at 6:23 AM, Bastien Latard | MDPI AG
<lat...@mdpi.com.invalid> wrote:
I just had a question about facets.
*==> Is the facet run on all documents (to pre-process/cache the data) or
only on returned documents?*
Yes ;-)
There are sometimes per-field data structures that are cached to
support faceting. This can make the first facet request after a new
searcher take longer. Unless you're using docValues, then the cost is
much less.
So how to force it to use docValues? Simply:
<field name="my_field" type="string" indexed="false" stored="false"
docValues="true" />
Are there other advantage/inconvenient?
Then there are per-request data structures (like a count array) that
are O(field_cardinality) and not O(matching_docs).
But then for default field-cache faceting, the actual counting part is
O(matching_docs).
So yes, at the end of the day we only facet on the matching
documents... but what the total field looks like certainly matters.
This would only be like that if I would use docValues, right?
If I have such field declaration (dedicated field for facet-- without
stemming), what would be the best setting?
<field name="author_facet" type="text_facet" indexed="true"
stored="true" required="false" multiValued="true" />
Kind regards,
Bastien
