Hello JJ, No, currently Impala uses one thread to execute the join (without regard for the amount of partitions that fit into memory).
HTH On 25 October 2017 at 05:44, 俊杰陈 <cjjnj...@gmail.com> wrote: > Hi > > When Impala does a partitioned join on a node, it split the build input > into partitions until a partition can fit into memory and consume the probe > input then do the join and output rows. > > My question is will impala schedule multiple tasks to do join if multiple > partitions fit into memory, or iterate over partitions? And for one > partition does it use multiple threads to do join? Thanks in advanced. > > > JJ
