This is easy to prove. Shut down Zookeeper, then send search requests to different hosts in the Solr Cloud cluster. If they work, then the requests are not going through Zookeeper.
wunder Walter Underwood wun...@wunderwood.org http://observer.wunderwood.org/ (my blog) > On Nov 29, 2016, at 9:44 AM, Erick Erickson <erickerick...@gmail.com> wrote: > > bq: My new place tells me they're sending requests to Zookeeper - and those > are > getting sent on to Solr by Zookeeper - -- this is news to me if it's true... > > Have you seen the code? Because if they're using SolrJ, then they do, indeed > connect to Zookeeper (i.e. CloudSolrClient takes a ZK ensemble) which they may > be misinterpreting as sending request to ZK that are forwarded to Solr. That > is > _not_ what's happening. The ZK connection allows SolrJ to get the > topology from ZK > but then CloudSolrClient sends requests to Solr nodes directly based > on the state.json > fetched from ZK. And it should cache that. > > There have been JIRAs about reducing the number of times any particular client > requests state.json from ZK, but there's _no_ code on ZK that forwards > requests. > ZK is just a bookkeeper, for it to "do the right thing" with a Solr > request it'd have to > know about Solr, i.e. we'd have to distribute some custom ZK code > which we don't. > > It would help if you provided the reason they think this. Code like above? > Network traffic? They've monitored the ZK activity and it's high? I.e. > is there any evidence of this? > > Best, > Erick > > > > On Tue, Nov 29, 2016 at 8:52 AM, Kevin Risden <compuwizard...@gmail.com> > wrote: >> If using CloudSolrClient or another zookeeper aware client, then a request >> gets sent to Zookeeper to determine the live nodes. If indexing, >> CloudSolrClient can find the leader and send documents directly there. The >> client then uses that information to query the correct nodes directly. >> >> Zookeeper is not forwarding requests to Solr. The client requests from >> Zookeeper and then the client uses that information to query Solr directly. >> >> Kevin Risden >> >> On Tue, Nov 29, 2016 at 10:49 AM, John Bickerstaff <j...@johnbickerstaff.com >>> wrote: >> >>> All, >>> >>> I've thought I understood that Solr search requests are made to the Solr >>> servers and NOT Zookeeper directly. (I.E. Zookeeper doesn't decide which >>> Solr server responds to requests and requests are made directly to Solr) >>> >>> My new place tells me they're sending requests to Zookeeper - and those are >>> getting sent on to Solr by Zookeeper - -- this is news to me if it's >>> true... >>> >>> Is there any documentation of exactly the role(s) played by Zookeeper in a >>> SolrCloud setup? >>>
