[FLINK-7401] EnvironmentInformation.getMaxJvmHeapMemory does not return the value given via -Xmx

• Type: Bug
• Status: Open
• Priority: Not a Priority
• Resolution: Unresolved
• Affects Version/s: 1.1.0, 1.1.1, 1.1.2, 1.1.3, 1.1.4, 1.2.0, 1.2.1, 1.3.0, 1.3.1, 1.3.2, 1.4.0
• Component/s: Runtime / Task
• Labels: auto-deprioritized-major auto-deprioritized-minor auto-unassigned
• Assignee: Unassigned
• Reporter: Nico Kruber
• Created: 09/Aug/17 14:07
• Updated: 01/Jan/22 10:39

Description

EnvironmentInformation.getMaxJvmHeapMemory is intended to return the value given to the JVM via -Xmx but it actually returns something a bit smaller which may disturb memory calculations expecting the right value.

For now, this is a "good" bug as the calculations inside TaskManagerServices#calculateNetworkBufferMemory(), for example, lead to lower values for the network buffers or the manages memory fractions which thus still fit into the bounds set by the JVM options.

Issue Links

• is related to: FLINK-5973 check whether the direct memory size is always correctly calculated
• links to: JDK-4391499 : java.lang.Runtime.maxMemory() returns value different from -Xmx option
• links to: workaround #1 getting {{-Xmx}} flag via {{MemoryPoolMXBean}}
• links to: workaround #2 getting {{-Xmx}} flag via {{ManagementFactory.getRuntimeMXBean().getInputArguments()}}
• links to: workaround #3 getting {{-Xmx}} flag via {{"sun.java.command"}} property