Gopal V created HIVE-16329:
------------------------------
Summary: TopN: TopNHash totalFreeMemory computation ignores free
memory
Key: HIVE-16329
URL: https://issues.apache.org/jira/browse/HIVE-16329
Project: Hive
Issue Type: Bug
Reporter: Gopal V
{code}
// TODO: For LLAP, assumption is off-heap cache.
final long memoryUsedPerExecutor =
(memoryMXBean.getHeapMemoryUsage().getUsed() / numExecutors);
// this is total free memory available per executor in case of LLAP
totalFreeMemory = conf.getMaxMemoryAvailable() - memoryUsedPerExecutor;
{code}
{code}
exec.TopNHash: isTez parameters -615768144 = 5312782848 - 71142611912 / 12
{code}
This turns off the TopNHash entirely causing something trivial like
{code}
select c_custkey, count(1) from customer group by c_custkey limit 10;
{code}
To shuffle 30M rows instead of 10.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
