RFR: JDK-8327769: jcmd GC.heap_dump without options should write to location given by -XX:HeapDumpPath, if set [v10]

[Chris Plummer]

On Wed, 3 Apr 2024 09:04:34 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

> > There's still the question of whether or not it is even appropriate to have -XX options taking the place of jcmd options.
> 
> Some people (like our cloud support colleagues and also some who commented) would like this approach, some find it not very useful. Seems there are also already other globals flags playing a role in diagnosticCommand coding (e.g. RecordDynamicDumpInfo, maybe more) so it is not completely 'new' that the jcmd commands are influenced by globals flag. Looking at just the _names_ of HeapDumpPath and also HeapDumpGzipLevel I would think that they play a role for all heap dumps and not just some.

That's a little different. For some reason (I'm not sure of the details) it was decided to not allow a dynamic dump with VM.cds unless it was explicitly enabled on the command line with the -XX:+ RecordDynamicDumpInfo option. This is different than having an jvm option that is used in place of an omitted jcmd option.

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PR Comment: https://git.openjdk.org/jdk/pull/18190#issuecomment-2035541597