Can anyone list scenarios where in Impala queries goes in "query waiting to be closed stage". i was checking one of IDs webUI and found bunch of queries listed under that section.
1. Why queries end up in that category, i guess timeout controls it(yet to do a bit of reading on that ).
2. Is it safe to close them or does that lead to any problems?
Queries are in the "waiting to be closed" stage if they are in the EXCEPTION state or if all the rows from the query have been read. In either case, the query needs to be explicitly closed for it to be "completed".
https://community.cloudera.com/t5/Support-Questions/Query-Cancel-and-idle-query-timeout-is-not-worki... might be useful as well.