Streaming expressions will utilize all replicas of a cluster when the number of workers >= the number of replicas.
For example if there are 40 workers and 40 shards and 5 replicas. For a single parallel request: Each worker will send 1 query to a random replica in each shard. This is 1600 hundreds requests. The 1600 requests will be spread evenly across all 200 nodes in the cluster, with each node handling 8 requests. Each request will return 1/1600 of the result set. If you add another row of replicas the 1600 hundred requests will be handled by 240 nodes. ----- In streaming expressions you use the parallel function to send requests to workers. In SQL you specify aggregationMode=map_reduce and workers=X. The SQL interface only goes into parallel mode for GROUP BY and SELECT DISTINCT queries. Joel Bernstein http://joelsolr.blogspot.com/ On Mon, May 23, 2016 at 7:17 PM, Joel Bernstein <joels...@gmail.com> wrote: > The image is the correct flow. Are you using workers? > > > > Joel Bernstein > http://joelsolr.blogspot.com/ > > On Mon, May 23, 2016 at 7:16 PM, Timothy Potter <thelabd...@gmail.com> > wrote: > >> This image from the wiki kind of gives that impression to me: >> >> >> https://cwiki.apache.org/confluence/download/attachments/61311194/cluster.png?version=1&modificationDate=1447365789000&api=v2 >> >> On Mon, May 23, 2016 at 11:50 AM, Erick Erickson >> <erickerick...@gmail.com> wrote: >> > I _think_ this is a distinction between >> > serving the query and processing the results. The >> > query is the standard Solr processing returning >> > results from one replica per shard. >> > >> > Those results can be partitioned out to N Solr instances >> > for sub-processing, where N is however many worker >> > nodes you specified that may or may not be host >> > to any replicas of that collection. >> > >> > At least I think that's what's up, but then again this is >> > new to me too. >> > >> > Which bits of the doc anyway? Sounds like some >> > clarification is in order. >> > >> > Best, >> > Erick >> > >> > On Mon, May 23, 2016 at 9:32 AM, Timothy Potter <thelabd...@gmail.com> >> wrote: >> >> I've seen docs and diagrams that seem to indicate a streaming >> >> expression can utilize all replicas of a shard but I'm seeing only 1 >> >> replica per shard (I have 2) being queried. >> >> >> >> All replicas are on the same host for my experimentation, could that >> >> be the issue? What are the circumstances where all replicas will be >> >> utilized? >> >> >> >> Or is this a mis-understanding of the docs? >> > >
