How to dump a RecordingStream?

[Gunnar Morling]

Good idea, thanks. It saves me one sec, nice.

--Gunnar


Am Mo., 23. Nov. 2020 um 12:29 Uhr schrieb Erik Gahlin <
erik.gahlin at oracle.com>:

> You can try to use RecordingStream and a Recording. Enable events using
> the stream, but dump using the Recording. It may keep things more in sync.
>
> Erik
>
> On 23 Nov 2020, at 12:22, Gunnar Morling <gunnar at hibernate.org> wrote:
>
> Hi Erik,
>
> Thanks for confirming, and +1 for enabling this use case in one way or
> another. The filtering idea sounds nice.
>
> So I'll go with the Recording + separate EventStream approach for now.
> From what I observe, it adds some latency, though: if I start the recording
> and the stream, it takes ~3 sec until I receive events emitted right
> thereafter. Not ideal for my testing use case, but not sure whether there's
> anything I can do about it. Things seemed faster when using
> RecordingStream. But as discussed, I'd then lack the ability to dump the
> stream if needed.
>
> Best,
>
> --Gunnar
>
>
> Am Mo., 23. Nov. 2020 um 11:50 Uhr schrieb Erik Gahlin <
> erik.gahlin at oracle.com>:
>
>> Hi Gunnar,
>>
>> There is no way to dump a RecordingStream.
>>
>> I have thought about the use case and prototyped it, but I have waited
>> with the implementation because I like to add a RemoteRecordingStream
>> first. It could impact the design.
>>
>> The workaround, like you describe, is to use a Recoding for control and
>> EventStream#openRepository() for reading the data.
>>
>> I’m also thinking of adding something more advanced where you can filter
>> out events to make the dumped recording smaller.
>>
>> Cheers
>> Erik
>>
>> > On 23 Nov 2020, at 10:00, Gunnar Morling <gunnar at hibernate.org> wrote:
>> >
>> > Hi,
>> >
>> > Is it possible to dump the underlying Recording of a JEP 349
>> > RecordingStream into a file at a given point in time?
>> >
>> > I can't seem to find any way for doing that; so what I'm currently
>> doing is
>> > to start a Recording, and then get a stream via
>> > EventStream.openRepository() which will expose the recording's events;
>> That
>> > way, I have a reference to the Recording instance and can call dump().
>> Is
>> > this the right way to do it? Perhaps it would make sense to have a
>> method
>> > dump() on RecordingStream(), too, so to simplify this?
>> >
>> > My use case is that I'm examining the JFR events based on the stream.
>> If it
>> > doesn't satisfy certain requirements, I'd like to dump the stream for
>> > offline analysis e.g. via JMC [1].
>> >
>> > Thanks a lot,
>> >
>> > --Gunnar
>> >
>> > [1] https://twitter.com/gunnarmorling/status/1330623384418455559
>> <https://urldefense.com/v3/__https://twitter.com/gunnarmorling/status/1330623384418455559__;!!GqivPVa7Brio!N7BRHMV7g4czu8LiNrSDaOYyeeQ0RbHMTHoKxl8FLq9p2ZYmydZac8IHBWJhhPa7$>
>>
>>
>