[AMBARI-24448] "Druid Historical" default MaxDirectMemorySize=1TB

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.6.2, 2.7.0
• Component/s: stacks
• Labels: common-services druid
• Assignee: Unassigned
• Reporter: Sean Roberts
• Created: 09/Aug/18 16:34
• Updated: 09/Aug/18 17:00

Description

By default, Ambari is giving "Druid Historical" component -XX:MaxDirectMemorySize=1048576m

I'm asking the Druid devs what a good default is, but 1TB of RAM is definitely too much! Once I get an answer, can send a pull request over.

`-XX:MaxDirectMemorySize` comes from druid-env. druid.historical.jvm.direct.memory and is appended with ‘m’:
https://github.com/apache/ambari/blob/trunk/ambari-server/src/main/resources/common-services/DRUID/0.10.1/package/scripts/druid.py#L109-L114

The default value is ‘1048576` which, when appeneded with 'm', is 1TB!:
https://github.com/apache/ambari/blob/trunk/ambari-server/src/main/resources/common-services/DRUID/0.10.1/configuration/druid-env.xml#L130-L131

Process listing:

$ ps aux | grep ^druid.*historical
druid     115683  0.0 15.6 97802020 82774676 ?   Sl   Jun08  66:48 /usr/java/default/bin/java -server -Xms2048m -Xmx2048m -XX:MaxDirectMemorySize=1048576m

In the JVM config file which Ambari manages:

$ grep MaxDirect /usr/hdp/current/druid-historical/conf/historical/jvm.config
-XX:MaxDirectMemorySize=1048576m