I had the chance to make some investigation code side,
and I basically confirm what Erick hypothesized and what Diego Ceccarelli
mentioned in this other thread [1].
Grouping happens with a 2 collector phases strategy :
1) first phase retrieve and sort the groups
2) second phase retrieve the top d
Alessandro:
I should have been explicit that I'm hypothesizing somewhat here, so
believe me at your own risk ;)
bq: So it means that group sorting is independent of the group head sorting
that's my hypothesis, but it's _not_ based on knowing the code.
Best,
Erick
On Wed, Apr 12, 2017 at 2:05 A
"You're telling Solr to return the highest scoring doc in each group.
However, you're asking to order the _groups_ in ascending score order
(i.e. the group with the lowest scoring doc first) of _any_ doc in
that group, not just the one(s) returned. These are two separate
things. "
This is quit
Skimming, I don't think this is inconsistent. First I assume that
you're OK with the second example, it's this one seems odd to you:
sort=score asc
group.sort=score desc
You're telling Solr to return the highest scoring doc in each group.
However, you're asking to order the _groups_ in ascending
I modified and cleaned the previous query. As you can see the first query
sorting is a bit odd.
Using parameters
sort=score asc
group.sort=score desc
http://localhost:8983/solr/mcontent.ph_post/select?=&fl=*,score&group.field=partnerId&group.limit=1&group.main=false&group.ngroups=true&gro
the group.sort spec is specified twice in the URL
group.sort=score desc&
group.sort=score desc
Is there a chance that during testing you only changed _one_ of them so you had
group.sort=score desc&
group.sort=score asc
? I think the last one should win.. Shot in the dark.
Best,
Erick
On Tue,
To be fair the second result seems consistent with the Solr grouping logic :
*First Query results (Suspicious)*
1) group.sort= score desc -> select the group head as you have 1 doc per
group( the head will be the top scoring doc per group)
2) sort=score asc -> sort the groups by the score of the h
