Sorry for interloping, but I have been wondering the same thing as Ryan. On
my current index with ~6.1M docs, I restarted Solr and ran a query that
included faceting on 4 fields:
QTime: 5712
numFound: 25908
filterCache stats:
lookups : 0
hits : 0
hitratio : 0.00
inserts : 1
evictions : 0
size : 1
cumulative_lookups : 0
cumulative_hits : 0
cumulative_hitratio : 0.00
cumulative_inserts : 1
cumulative_evictions : 0
Then I added faceting on a 5th, multivalued field:
QTime: 65551
numFound: 25908
Filtercache stats:
lookups : 1898314
hits : 1
hitratio : 0.00
inserts : 1898314
evictions : 1897802
size : 512
cumulative_lookups : 1898314
cumulative_hits : 1
cumulative_hitratio : 0.00
cumulative_inserts : 1898314
cumulative_evictions : 1897802
I realize there are a lot of different values in the 5th multivalued field.
But this is where I'm fuzzy: are we saying there would be no difference
using a tokenized, single valued field versus a multivalued field? Or are we
saying that multivalued is ok, as long as the number of values is less than
the filterCache size? [Unfortunately I don't have a single valued version of
this field to test with]
Thanks,
-Graham
> I'll be interested in seeing some numbers. The number of
> documents matching the base query and filters will also
> factor in (small will be HashDocSet, large will be BitDocSet).
>
> Just make sure to run all of your facets, then check the
> statistics page to see how big you need to make the
> filterCache to hold them all (and add a little extra for
> random filters). The access pattern for the faceting code is
> worst case for the LRU cache, so it needs to avoid any evictions.
>
> -Yonik
