I have enabled automatic heap dump generation on Websphere application server 8.5.5 by below steps.
Appserver>>process definition>>environment entries
Added below 2 entries.
IBM_HEAPDUMP = TRUE
IBM_HEAPDUMP_OUTOFMEMORY = TRUEI just want to know how frequently heap dump will be generated? example out of 15 request. 10 request, we have faced outofMemoryerror: java heap space. Heap dump will generate for 1 time or 10 times?
There is no such feature using environment variables.
The IBM_HEAPDUMP is only useful to set to false to completely disable heapdumps. Setting it to true is redundant because that is the default.
The same is true of IBM_HEAPDUMP_OUTOFMEMORY. Taking a heapdump on an OutOfMemoryError is enabled by default.
You can find more information on these environment variables here: https://www.ibm.com/support/knowledgecenter/SSYKE2_8.0.0/com.ibm.java.vm.80.doc/docs/env_j9.html
Note that envars to control dumps are no longer recommended in favor of -Xdump: https://www.ibm.com/support/knowledgecenter/SSYKE2_8.0.0/com.ibm.java.vm.80.doc/docs/dump_agents.html
With that said, there is no such feature as automatically generating heapdumps without some trigger. You can find various way on how to request heapdumps here: https://publib.boulder.ibm.com/httpserv/cookbook/Troubleshooting-Troubleshooting_WebSphere_Application_Server-Troubleshooting_WAS_Traditional.html#Troubleshooting-Troubleshooting_WAS_Traditional-Request_Heap_Dump
The easiest way is probably to script it. You haven't specified which operating system you're on, but I'll guess it's POSIX-based with IBM Java, so I would use Java Surgery with a shell script:
#!/bin/sh
while true; do
java -jar surgery.jar -command HeapDump -pid $1
sleep $2
done