Hi Joel, Thanks for the information.
Regards, Edwin On 25 March 2017 at 10:15, Joel Bernstein <joels...@gmail.com> wrote: > The innerJoin is a merge join and the hashJoin is a hash join. > > The merge join can support joins of unlimited size and never runs out of > memory. But it requires that both sides of the join are sorted on the join > keys. > > The hash join reads one side of the join into a hash map keyed on the join > keys. This doesn't require any specific sort but it is limited in size by > how much data can fit in the hash map. > > You can parallelize both joins using the parallel function to improve > scalability and performance. > > Joel Bernstein > http://joelsolr.blogspot.com/ > > On Fri, Mar 24, 2017 at 4:49 AM, Zheng Lin Edwin Yeo <edwinye...@gmail.com > > > wrote: > > > Hi, > > > > What is the main difference between hashJoin and innerJoin in Solr > > Streaming Expression? > > > > I understand that both will emit a tuple containing the fields of both > > tuples. > > > > When I tried both hashJoin and innerJoin with the same query, I get > exactly > > the same results, and there is no difference in performance. > > > > Under what circumstances should we use hashJoin, and under what > > circumstances should we use innerJoin? > > > > Regards, > > Edwin > > >
