JEP 158: Unified JVM logging

Wed Aug 15 08:56:07 UTC 2012

Hi Dmitry,

I should have added that Neal Ford has an excellent talk on taxonomy systems and tags vs. hierarchies. It includes a bit on the 5 kingdoms that all organisms are split into. Yet many organisms show characteristics from more than one kingdom while some others show characteristics of none. Problem is, the current hierarchical system forces categorization in a way that doesn't work where as a tag system would easily be able to cope. I'm trying to find a link to the talk.

Regards,
Kirk

On 2012-08-14, at 12:17 PM, Dmitry Samersoff <Dmitry.Samersoff at oracle.com> wrote:

> Kirk,
> 
>> However I do have very serious concerns about this JEP in that it
>> doesn't fix the problems that exist in current logging frameworks,
>> it only mimics them.
> 
>> http://openjdk.java.net/jeps/158
> 
> Any comments is much appreciated.
> 
> Personally, I think that log rotation is out of scope and responsibility
> of JVM.
> 
> -Dmitry
> 
> 
> On 2012-08-14 13:26, Kirk Pepperdine wrote:
>> Hi Yasumasa,
>> 
>> I'm not sure that log file rotation is a part of this JEP. 
>> However I do have very serious concerns about this JEP in that it doesn't fix the problems that exist in current logging frameworks, it only mimics them.
>> 
>> Regards,
>> Kirk
>> 
>> On 2012-08-14, at 11:20 AM, Yasumasa Suenaga <suenaga.yasumasa at lab.ntt.co.jp> wrote:
>> 
>>> Hi Staffan,
>>> 
>>> May I ask you 2 questions about this JEP?
>>> 
>>> 1. One of goals of this JEP is defined as following:
>>>     "File rotation of log files by size (similar to what is available for GC logs today)"
>>>   My patch realizes log rotation by external trigger.
>>>   7090324 is included in this JEP?
>>>   (Is 7090324 included in "Logging can be configured dynamically at runtime via jcmd or MBeans" ? )
>>> 
>>> 2. I've posted a patch for "6950794: Make the GC log file name parameterized" .
>>>     http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2012-July/004758.html
>>>   Could you include this RFE in this JEP?
>>>   If we use log rotation, I think that name of logs is very important for log management.
>>> 
>>> 
>>> Thanks,
>>> 
>>> Yasumasa
>>> 
>>> 
>>> On 2012/08/14 16:50, Staffan Larsen wrote:
>>>> Hi Yasumasa,
>>>> 
>>>> This work should be done in the context of the Unified Logging JEP [1]. Unfortunately, that work has not yet started due to resource constraints. Comments on the proposal are welcome.
>>>> 
>>>> [1] http://openjdk.java.net/jeps/158
>>>> 
>>>> /Staffan
>>>> 
>>>> On 31 jul 2012, at 12:45, Yasumasa Suenaga <suenaga.yasumasa at lab.ntt.co.jp <mailto:suenaga.yasumasa at lab.ntt.co.jp>> wrote:
>>>> 
>>>>> Hi,
>>>>> 
>>>>> I've posted a patch for gc log rotation via jinfo tool last year.
>>>>> Then I received an email that essence of my patch will be implemented as
>>>>> "subcommands" of jcmd.
>>>>> 
>>>>> Now, jcmd is provided by OpenJDK. However, current jcmd does not seem to
>>>>> implement function of gclog rotation.
>>>>> 
>>>>> Will this RFE be implemented?
>>>>> 
>>>>> I need to rotate gclog which is synchronized with signal, cron, etc... on Linux.
>>>>> So, if this RFE is not implemented for a while, I would like to contribute
>>>>> patch for jcmd.
>>>>> 
>>>>> 
>>>>> Regards,
>>>>> 
>>>>> Yasumasa
>>>>> 
>>>>> 
>>>>> On 2011/09/29 21:15, James Melvin wrote:
>>>>>> Hi Yasumasa,
>>>>>> 
>>>>>> Thanks very much for your OpenJDK contribution! As part of the effort to
>>>>>> port JRockit features to HotSpot, we plan to introduce a consolidated
>>>>>> commandline serviceability tool (jcmd) to potentially replace many of
>>>>>> the existing tools in the bin directory, such as jmap, jstack, jinfo and
>>>>>> others. Over the next few update releases, we plan to add several jcmd
>>>>>> *subcommands* instead to accomplish specific tasks or affect the running
>>>>>> JVM instance. We'd like to use the essence of your contribution in one
>>>>>> of the jcmd subcommands (instead of extending jinfo) to ask the JVM to
>>>>>> begin rotating GC logs. We hope you find this attractive and hope you
>>>>>> will help review and perfect the change.
>>>>>> 
>>>>>> Thanks,
>>>>>> 
>>>>>> Jim Melvin
>>>>>> Sr. Engineering Manager
>>>>>> Oracle
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> On 9/26/11 6:38 AM, Yasumasa Suenaga wrote:
>>>>>>> (I've changed subject of this email to new RFE.)
>>>>>>> 
>>>>>>> This RFE is enhancement of current gclog implementation.
>>>>>>> So, I'd like to discuss about rotating gclog.
>>>>>>> 
>>>>>>> My customers need gclog rotation which is invoked by external trigger.
>>>>>>> So I've requested this RFE and made a patch.
>>>>>>> 
>>>>>>> 
>>>>>>> In many case on Linux, logfile is rotated by signal (e.g. SIGHUP) .
>>>>>>> The aim of this RFE is to synchronize gclog and the other logs.
>>>>>>> 
>>>>>>> 
>>>>>>> Thanks,
>>>>>>> 
>>>>>>> Yasumasa
>>>>>>> 
>>>>>>> (2011/09/22 20:55), Rainer Jung wrote:
>>>>>>>> On 22.09.2011 13:20, Dmitry Samersoff wrote:
>>>>>>>>> 
>>>>>>>>> Yasumasa,
>>>>>>>>> 
>>>>>>>>> On 2011-09-22 04:47, Yasumasa Suenaga wrote:
>>>>>>>>>> If we can think Java on Linux and Solaris only, syslog is best
>>>>>>>>>> solution.
>>>>>>>>>> However, Windows usually doesn't have syslog.
>>>>>>>>>> 
>>>>>>>>>> So, I think that gclog is needed for logging GC stats with platform
>>>>>>>>>> independent in realtime.
>>>>>>>>> 
>>>>>>>>> Windows has it's own logging API as reach as syslog is or ever better
>>>>>>>>> as well as numerous syslog implementations.
>>>>>>>>> 
>>>>>>>>> Native windows logging API was completely redesigned for Windows 2008
>>>>>>>>> server and now it allows for developers to send a structured events from
>>>>>>>>> theirs application.
>>>>>>>> 
>>>>>>>> AFAIK log rotation for loggc is already implemented though not
>>>>>>>> necessarily yet released. The change discussed here is about supporting
>>>>>>>> an externally generated rotation trigger, e.g. via a signal, instead of
>>>>>>>> only rotating by size or time via a startup parameter.
>>>>>>>> 
>>>>>>>> If you want support for syslog or Windows APIs included, it would be
>>>>>>>> best to start a new discussion.
>>>>>>>> 
>>>>>>>> A GC log for an application under load might easily produce a block of
>>>>>>>> about 1.5 KB size every few seconds. I seriously doubt, that the need
>>>>>>>> for log file rotation can be argued away by referring to syslog or
>>>>>>>> Windows log API as the correct solution.
>>>>>>>> 
>>>>>>>> The messages are not really line formatted, the format can vary a lot
>>>>>>>> (depending on the excat XX switches), the traffic can be quite high and
>>>>>>>> AFAIK the JVM writes it synchronously, so there must be absolutely no
>>>>>>>> risk in writing it out with very little latency. In addition, for
>>>>>>>> analysis, you wouldn't want to look at each event individually, but
>>>>>>>> instead process the whole file through a script or tool, which should
>>>>>>>> not depend on the output specifics of a platform specific log apparatus.
>>>>>>>> 
>>>>>>>> Regards,
>>>>>>>> 
>>>>>>>> Rainer
>>>>>>>> 
>>>>>>> 
>>>>> 
>>>> 
>>> 
>> 
> 
> 
> -- 
> Dmitry Samersoff
> Java Hotspot development team, SPB04
> * There will come soft rains ...
> 
> 