This is a known issue that we're actively working on: https://issues.cloudera.org/browse/IMPALA-2567   Your analysis is accurate. Part of the problem is the number of connections and the other part is the # of threads per connection. You may be able to change some operating system config settings to increase limits here (depending on which limit you're hitting).   In order to reduce the # of tcp conncetions required you would either need to reduce the number of fragments or reduce the number of node executing the query.   You could reduce the # of fragments by breaking up the query into smaller queries. E.g. creating temporary tables with the results of some of the subqueries.  You could also try executing the query on a single node by setting num_nodes=1 if the data size is small enough that this makes sense. I suspect your query is too large for that to work, but it's hard to tell (that's a huge query plan!) ... View more

I'm not the most knowledgeable person about this part of the code, but what you're saying is correct. One of the likely causes of long wait times is if the receiver is consuming data slower than the sender is sending it. ... View more

We're working on it and it should be in the next release, but unfortunately we're not aware of a good way to simulate the same results. ... View more

The only way to do this with zero work would be to use a view. http://www.cloudera.com/documentation/enterprise/latest/topics/impala_create_view.html    Otherwise you do have to run the queries as part of your data pipeline as you mentioned.     ... View more