Aggregating data with Solr, getting group stats

[Bojan Šmid <bo...@gmail.com>]

Hi,

  I see there are few ways in Solr which can "almost" be used for my use
case, but all of them appear to fall short eventually.

  Here is what I am trying to do: consider the following document structure
(there are many more fields in play, but this is enough for example):

Manufacturer
ProductType
Color
Size
Price
CountAvailableItems

  Based on user parameters (search string, some filters), I would fetch a
set of documents. What I need is to group resulting documents by different
attribute combinations (say "Manufacturer + Color" or "ProductType + Color
+ Size" or ...) and get stats (Max Price, Avg Price, Num of available
items) for those groups.

  Possible solutions in Solr:

1) StatsComponent - provides all stats I would need, but its grouping
functionality is basic - it can group on a single field (stats.field +
stats.facet) while I need field combinations. There is an issue
https://issues.apache.org/jira/browse/SOLR-2472 which tried to deal with
that, but it looks like it got stuck in the past.

2) Pivot Faceting - seems like it would provide all the grouping logic I
need and in combination with
https://issues.apache.org/jira/browse/SOLR-3583"Percentiles for
facets, pivot facets, and distributed pivot facets" would
bring percentiles and averages. However, I would still miss things like
Max/Min/Sum and the issue is not committed yet anyway. I would also depend
on another yet to be committed issue
https://issues.apache.org/jira/browse/SOLR-2894 for distributed support.

3) Configurable Collectors -
https://issues.apache.org/jira/browse/SOLR-4465- seems promissing, but
it allows grouping by just one field and, probably
a bigger problem, seem it was just a POC and will need overhauling before
it is anywhere near being ready for commit


  Are there any other options I missed?

  Thanks,

  Bojan