Hello Chris,

Yes, I am talking about the access log

Regards,
Poojashree Prakash

On Wed, Sep 17, 2025 at 5:42 PM Christopher Schultz <
[email protected]> wrote:

> Poojashree,
>
> On 9/17/25 3:29 AM, Poojashree Prakash wrote:
> > I was referring to adding precision in the log’s time field, with an
> option
> > to record in microseconds or finer.
> > This would be similar to the request time support introduced in Tomcat 10
> > and above, which allows using %D. Reference: Tomcat
> AbstractAccessLogValve
> > <
> https://tomcat.apache.org/tomcat-10.1-doc/api/org/apache/catalina/valves/AbstractAccessLogValve.html#log(org.apache.catalina.connector.Request,org.apache.catalina.connector.Response,long)
> >
>
> I'm mostly trying to confirm that you are talking about the ACCESS LOG
> and not some other kind of log.
>
> Thanks,
> -chris
>
> > On Wed, Sep 17, 2025 at 12:44 AM Christopher Schultz <
> > [email protected]> wrote:
> >
> >> Poojashree,
> >>
> >> On 9/15/25 6:26 AM, Poojashree Prakash wrote:
> >>> The request is not to change the default logging format, but to have an
> >>> option in Tomcat logging to include microseconds in the timestamp.
> Having
> >>> this option would allow us to enable microsecond precision only when
> >>> needed, for detailed debugging.
> >>
> >> This is for the access log valve, right?
> >>
> >> There was some work recently done to measure request timings in a
> >> variety of precisions.
> >>
> >> But you are talking about the format of the end-of-request timestamp,
> >> correct?
> >>
> >> -chris
> >>
> >>> On Mon, Sep 15, 2025 at 2:48 PM [email protected]
> >>> <[email protected]> wrote:
> >>>
> >>>> I may be mistaken:
> >>>>
> >>>> This may have implications on tools like fail2ban, who may read log
> >>>> files, probably not with microseconds.
> >>>>
> >>>> If Tomcat would use microsecond-precision timestamps in logs, this
> >>>> should be an option only.
> >>>>
> >>>> Regards
> >>>> Markus
> >>>>
> >>>>
> >>>> Am 15.09.25 um 11:02 schrieb Poojashree Prakash:
> >>>>> The main motivation to have microsecond-precision timestamps in logs
> is
> >>>> for
> >>>>> detailed debugging and performance analysis.
> >>>>>
> >>>>> Other Java-based servers, such as WildFly, are already considering
> >>>> support
> >>>>> for microsecond-level logging  -
> >>>>> https://stackoverflow.com/users/152794/james-r-perkins
> >>>>>
> >>>>> Could this be considered, and we would like to know if, similar to
> >>>> WildFly,
> >>>>> there are any plans to implement microsecond-precision logging in
> >> Tomcat.
> >>>>> If there is a limitation with tomcat9 and below, could it be
> considered
> >>>> for
> >>>>> tomcat 10 and above.
> >>>>>
> >>>>> Regards,
> >>>>> Poojashree Prakash
> >>>>>
> >>>>> On Fri, Sep 12, 2025 at 8:38 PM Harri Pesonen
> >>>>> <[email protected]> wrote:
> >>>>>
> >>>>>> java.lang.Instant comes with Java 8 but there it does not have
> >>>> microsecond
> >>>>>> precision yet (it can store even nanoseconds but they are all
> zeros).
> >>>>>>
> >>>>>> Personally I don't see much reason for microsecond precision in logs
> >>>>>> either, but perhaps it could be an option.
> >>>>>>
> >>>>>> -Harri
> >>>>>>
> >>>>>> -----Original Message-----
> >>>>>> From: Mark Thomas<[email protected]>
> >>>>>> Sent: perjantai 12. syyskuuta 2025 17.44
> >>>>>> To: Tomcat Users List<[email protected]>
> >>>>>> Subject: Re: Support for microsecond precision in timestamps (Tomcat
> >>>>>> 9.0.108 / 10.1.44)
> >>>>>>
> >>>>>> On 12/09/2025 13:00, Poojashree Prakash wrote:
> >>>>>>> +1
> >>>>>>> Java9 and above supports precision logging -  timestamp - Current
> >> time
> >>>>>>> in microseconds in java - Stack Overflow
> >>>>>>> <
> >> https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsta
> >>>>>>> ckoverflow.com
> >> %2Fquestions%2F1712205%2Fcurrent-time-in-microseconds-in
> >>>>
> >>>>>>> -java&data=05%7C02%7Charri.pesonen%40sinch.com
> >> %7C668025699f024c646b6f0
> >>>>
> >>>>>>>
> >> 8ddf20af08e%7C3b518aae89214a7b8497619d756ce20e%7C0%7C0%7C6389328510157
> >>>>>>>
> >> 79455%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAw
> >>>>>>>
> >> MCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdat
> >>>>>>> a=33veKYxAmaT4XVPSo65DLVb7T31t%2BZaujXAG6HHqNjk%3D&reserved=0>
> >>>>>>> Also considering - Apache Tomcat(r) - Which Version Do I Want?
> >>>>>>> <
> >> https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftom
> >>>>>>> cat.apache.org
> >> %2Fwhichversion.html&data=05%7C02%7Charri.pesonen%40sinc
> >>>>
> >>>>>>> h.com
> >> %7C668025699f024c646b6f08ddf20af08e%7C3b518aae89214a7b8497619d756
> >>>>
> >>>>>>>
> >> ce20e%7C0%7C0%7C638932851015805837%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1
> >>>>>>>
> >> hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUI
> >>>>>>>
> >> joyfQ%3D%3D%7C0%7C%7C%7C&sdata=qSqG%2BLOpgY1iZSBhK2PmGaQ1lp0i2m2O6wGCU
> >>>>>>> HBjIWM%3D&reserved=0>
> >>>>>>>
> >>>>>>> tomcat11 Supports java 17 and above
> >>>>>>> tomcat10 Support java 11 and above
> >>>>>>> tomcat9 Supports java 8 and above
> >>>>>>> So, does Tomcat provide any way to log access timestamps with
> >>>>>>> microsecond precision?
> >>>>>>> If not, is there an upcoming plan to enable true microsecond
> >> precision
> >>>>>>> in timestamps for Tomcat logs?
> >>>>>> I stand corrected.
> >>>>>>
> >>>>>> There are no currently plans for microsecond precision in timestamps
> >> for
> >>>>>> either logs or the access log.
> >>>>>>
> >>>>>> There are a number of things any implementation would need to take
> >>>> account
> >>>>>> of:
> >>>>>>
> >>>>>> - Tomcat 9 has a minimum Java version of 8 so Instant might not be
> >>>>>>       available for log messages. It is likely some form of
> JreCompat
> >>>> based
> >>>>>>       solution would be required for Tomcat 9
> >>>>>>
> >>>>>> - Converting the timestamps to strings would need some thought. The
> >>>>>>       timestamp to String conversions in Tomcat are heavily
> optimised
> >> for
> >>>>>>       performance. Work would be required to determine if that were
> >> still
> >>>>>>       necessary and, if it were, to develop appropriate solutions
> >>>>>>
> >>>>>> - The access log valve implementations would need to be converted to
> >> use
> >>>>>>       Instant. A bigger issue is the API uses milliseconds. The API
> and
> >>>>>>       configuration would need to be updated in a backwards
> compatible
> >> way
> >>>>>>       for this to be available on anything earlier than Tomcat 12.
> >>>>>>
> >>>>>> All of which begs the question. Why? What is it that you are trying
> to
> >>>> do
> >>>>>> that you can't do with the current millisecond logs and microseconds
> >> for
> >>>>>> request processing time?
> >>>>>>
> >>>>>> Mark
> >>>>>>
> >>>>>>
> >>>>>>
> ---------------------------------------------------------------------
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> >>>>>> For additional commands, e-mail:[email protected]
> >>>>>>
> >>>>>>
> >>>>>>
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> >>>>>> For additional commands, e-mail:[email protected]
> >>>>>>
> >>>>>>
> >>>
> >>
> >>
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> >>
> >>
> >
>
>
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