Hi @saikat  As I can understand you are running a merge query and it is failing with java.lang.OutOfMemoryError error.   Step 1: Could you please run major compaction on all the tables involves in the merge query(If it is an ACID table or else ignore step1). Once the major compaction is triggered make sure it got completed by running "show compactions;" command in the beeline. This will bring down some stats collection burden for the hive. How to run minor and major compaction? Alter table <table name> compact 'MAJOR'; Step 2: Once step1 is done. Please set the following propery in beeline session level and re-run the merge query set hive.tez.container.size=16384; set hive.tez.java.opts=-Xmx13107m; set tez.runtime.io.sort.mb=4096; set tez.task.resource.memory.mb=16384; set tez.am.resource.memory.mb=16384; set tez.am.launch.cmd-opts=-Xmx13107m; set hive.auto.convert.join=false; The TEZ container and AM size is set as 16GB, if the query got failed you can increase the value to 20GB(then hive.tez.java.opts and tez.am.launch.cmd-opts need to be configured 80% of container and AM size that is 16384). If the query got succeeded with 16GB of TEZ container and AM size then you can try to decrease it too 14/12/10 and figure out a benchmark where it is failing and getting succeeded. In this way, you can save resources. If you are happy with the comment, Mark it "Accept as Solution". ... View more