Forgot to answer your second question: > Can I trigger the "fixing" mechanism that Solr runs at restart by an API call > or some other method?
It depends on what the cause is. But for at least some possible causes there is an API call that can resolve this. Though that API itself (Solr's misnamed "optimize" feature) comes with a lot of warnings and has been discouraged by the community in the past. (I won't get into those specifics though until you figure out the cause.) Before you consider calling "optimize" or taking any other means to fix this though, it might be worth revisiting whether this is really an issue? While this quirk of Solr's can bedevil automated tests or other things that rely on repeatability, it's unusual in many applications for end-users to submit identical queries multiple times. Every case is different of course, but something to consider. Best, Jason On Mon, Feb 1, 2021 at 3:49 PM Jason Gerlowski <gerlowsk...@gmail.com> wrote: > > Hi Ronen, > > The first thing I'd figure out in your situation is whether the > results are actually different each time, or whether the ordering is > what differs (which might push a particular result off the page you're > looking at, giving the appearance that it didn't match). > > In the case of the former, this can happen briefly if queries come in > when some but not all replicas have seen a commit. But usually this > is a transient concern - either waiting for the next autocommit or > triggering an explicit commit resolves the discrepancy in this case. > Since you only see identical results after a restart, this _doesn't_ > sound like what you're seeing. > > In the case of the latter (same results, differently ordered) this is > expected sometimes. Solr sorts on relevance by default with the > internal Lucene document ID being a tiebreaker. Both the relevance > statistics and Lucene's document IDs can differ across SolrCloud > replicas (due to non-deterministic conditions such as the segment > merging and deleted-doc removal that Lucene does under the hood), and > this can produce differently-ordered result sets for users that issue > the same query repeatedly. > > Good luck narrowing things down! > > Jason > > On Mon, Jan 25, 2021 at 3:32 AM Ronen Nussbaum <rone...@gmail.com> wrote: > > > > Hi All, > > > > I'm using Solr Cloud (version 8.3.0) with shards and replicas (replication > > factor of 2). > > Recently, I've encountered several times that running the same query > > repeatedly yields different results. Restarting the nodes fixes the problem > > (until next time). > > I assume that some shards are not synchronized and I have several questions: > > 1. What can cause this - many atomic updates? issues with commits? > > 2. Can I trigger the "fixing" mechanism that Solr runs at restart by an API > > call or some other method? > > > > Thanks in advance, > > Ronen.
