Hi Ghousia, I believe that Hadoop has a default FIFO scheduler for MapReduce jobs by default. Also, as a corollary, the second MapReduce job wouldn't get started until the first one is done. If you are using FIFO scheduler in Hadoop, even if you issue 2 Hive queries, the second one's MapReduce job wouldn't get started until the first one is done (someone correct me if I wrong).
I do know that Hadoop now has some pluggable schedulers like Capacity Scheduler and Fair Scheduler which you might want to look into. More details here: http://hadoop.apache.org/mapreduce/docs/r0.21.0/capacity_scheduler.html http://hadoop.apache.org/mapreduce/docs/r0.21.0/fair_scheduler.html Mark ----- Original Message ----- From: "Mapred Learn" <mapred.le...@gmail.com> To: user@hive.apache.org Sent: Tuesday, November 15, 2011 2:15:59 PM Subject: Re: Asynchronous query exection You could write your query to a file and do something like: hive -f <filename1> & hive -f <filename2> & etc. to invoke many instances in parallel. On Tue, Nov 15, 2011 at 3:24 AM, Chinna Rao Lalam < chinna...@huawei.com > wrote: Hi, Hive calls are blocking calls because once the query is executed it will return the ResultSet from that result set u will get the results. "hive.exec.parallel" property will helps to speed up the query execution if the query generates more than one independent tasks. If it generates independent tasks if this property is true it will execute the independent tasks parallely otherwise it will execute sequentially. Thanks&Regards, Chinna Rao Lalam From: Ghousia [ ghousia.ath...@gmail.com ] Sent: Tuesday, November 15, 2011 6:12 PM To: user@hive.apache.org Subject: Asynchronous query exection Hi, Hive queries take longer time to execute, and by default it is a blocking call. Is there any way provided by Hive client to supports non blocking execution. Also, to execute jobs parallely, I tried setting the "hive.exec.parallel" to true in hive-site.xml. But this did not work, Looking at the code, it looks like the same flow is been followed both for serial and parallel execution. Any inputs would be of great help. Thanks, Ghousia.
