Perfect Joel, keep me updated ! Cheers
On Mon, Sep 19, 2016 at 10:26 PM, Joel Bernstein <joels...@gmail.com> wrote: > Alessandro, I'll be doing some testing with the re-ranker as part of > SOLR-9403 for Solr 6.3. I'll see if I can better understand the issue > you're bringing up during the testing. I'll report back to this thread > after I've done some testing. > > Joel Bernstein > http://joelsolr.blogspot.com/ > > On Fri, Sep 16, 2016 at 11:17 AM, Alessandro Benedetti < > abenede...@apache.org> wrote: > > > In addition to that, I think the only way to solve this is to rely on the > > aggregator node to actually re-rank after having aggregated. > > > > Cheer > > > > On Fri, Sep 9, 2016 at 11:48 PM, Alessandro Benedetti < > > abenede...@apache.org > > > wrote: > > > > > Let me explain further, > > > let's assume a simple case when we have 2 shards. > > > ReRankDocs =10 , rows=10 . > > > > > > Correct me if I am wrong Joel, > > > What we would like : > > > 1 page : top 10 re-scored > > > 2 page: remaining 10 re-scored > > > From page 3 the original scored docs. > > > This is what is happening in a single sol instance if we put reRankDocs > > to > > > 20. > > > > > > Let's see with sharing : > > > To get the first page we get top 10 ( re-scored) from shard1 and top 10 > > > reranked for shard 2. > > > Then the merged top 10 ( re-scored) will be calculated, and that is the > > > page 1. > > > > > > But when we require the page 2, which means we additionally ask now : > > > 20 docs to shard1, 10 re-scored and 10 not. > > > 20 docs to shard2, 10 re-scored and 10 not. > > > At this point we have 40 docs to merge and rank.. > > > The docs with the original score can go at any position ( not > necessarily > > > the last 20) > > > In the page 2 we can find potentially docs with the original score. > > > This is even more likely if the scores are on differente scales (e.g. > the > > > re-scored 0<x<1 and original >100 ) . > > > > > > Am I right ? > > > Did I make any wrong assumption so far ? > > > > > > Cheers > > > > > > > > > On Fri, Sep 9, 2016 at 7:47 PM, Joel Bernstein <joels...@gmail.com> > > wrote: > > > > > >> I'm not understanding where the inconsistency comes into play. > > >> > > >> The re-ranking occurs on the shards. The aggregator node will be sent > > some > > >> docs that have been re-scored and others that are not. But the sorting > > >> should be the same as someone pages through the result set. > > >> > > >> > > >> > > >> Joel Bernstein > > >> http://joelsolr.blogspot.com/ > > >> > > >> On Fri, Sep 9, 2016 at 9:28 AM, Alessandro Benedetti < > > >> abenede...@apache.org> > > >> wrote: > > >> > > >> > Hi guys, > > >> > was just experimenting some reranker with really low number of > rerank > > >> docs > > >> > ( 10= pageSize) . > > >> > Let's focus on the distributed enviroment and the manual sharding > > >> > approach. > > >> > > > >> > Currently what happens is that the reranking task is delivered by > the > > >> > shards, they rescore the docs and then send them back to the > > aggregator > > >> > node. > > >> > > > >> > If you want to rerank only few docs ( leaving the others with the > > >> original > > >> > score following), this can be done in a single Solr instance ( the > > >> howmany > > >> > logic manages that in the reranker) . > > >> > > > >> > What happens when you move to a distributed environment ? > > >> > The aggregator will aggregate both rescored and original scored > > >> documents, > > >> > making the final ranking inconsistent. > > >> > In the other hand if we make the rarankingDocs threshold dynamic ( > to > > >> adapt > > >> > to start+rows) we can incur in the very annoying issue of having a > > >> document > > >> > sliding through the pages ( visible in the first page , then > appearing > > >> > again in the third ect ect). > > >> > > > >> > Any thought ? > > >> > > > >> > Cheers > > >> > > > >> > -- > > >> > -------------------------- > > >> > > > >> > Benedetti Alessandro > > >> > Visiting card : http://about.me/alessandro_benedetti > > >> > > > >> > "Tyger, tyger burning bright > > >> > In the forests of the night, > > >> > What immortal hand or eye > > >> > Could frame thy fearful symmetry?" > > >> > > > >> > William Blake - Songs of Experience -1794 England > > >> > > > >> > > > > > > > > > > > > -- > > > -------------------------- > > > > > > Benedetti Alessandro > > > Visiting card : http://about.me/alessandro_benedetti > > > > > > "Tyger, tyger burning bright > > > In the forests of the night, > > > What immortal hand or eye > > > Could frame thy fearful symmetry?" > > > > > > William Blake - Songs of Experience -1794 England > > > > > > > > > > > -- > > -------------------------- > > > > Benedetti Alessandro > > Visiting card : http://about.me/alessandro_benedetti > > > > "Tyger, tyger burning bright > > In the forests of the night, > > What immortal hand or eye > > Could frame thy fearful symmetry?" > > > > William Blake - Songs of Experience -1794 England > > > -- -------------------------- Benedetti Alessandro Visiting card : http://about.me/alessandro_benedetti "Tyger, tyger burning bright In the forests of the night, What immortal hand or eye Could frame thy fearful symmetry?" William Blake - Songs of Experience -1794 England
