@sgiri - This has already been answered above. If you use un-secure YARN, all your containers and the commands the container runs (such as in shell action) will run as the "yarn" user (i.e. the user your NodeManager daemon runs as). If you want to run containers in YARN as the actual submitting user, use the LinuxContainerExecutor instead. The caveat of using it is that you need your user accounts available on all NodeManagers so a setuid can be done against them when spawning the container processes. ... View more

You can create a 1-row dummy table like this:   select 1 id, 'a' d from (select 1) dual where 1 = 1   You also have to rewrite the query to avoid an uncorrelated not exists. You can do something like:   select 1 id, 'a' d from (select 1) dual where (select count(*) from employee where empid > 20000) = 0   Computing the count might be expensive so you could add a limit like   select 1 id, 'a' d from (select 1) dual where (select count(*) from (select id from employee where empid > 20000 limit 1) emp) = 0 ... View more