Hello Chris, 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)>
Regards, Poojashree Prakash On Wed, Sep 17, 2025 at 12:44 AM Christopher Schultz < ch...@christopherschultz.net> 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 i...@flyingfischer.ch.INVALID > > <i...@flyingfischer.ch.invalid> 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 > >>> <harri.peso...@sinch.com.invalid> 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<ma...@apache.org> > >>>> Sent: perjantai 12. syyskuuta 2025 17.44 > >>>> To: Tomcat Users List<users@tomcat.apache.org> > >>>> 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 > >>>> > >>>> > >>>> --------------------------------------------------------------------- > >>>> To unsubscribe, e-mail:users-unsubscr...@tomcat.apache.org > >>>> For additional commands, e-mail:users-h...@tomcat.apache.org > >>>> > >>>> > >>>> --------------------------------------------------------------------- > >>>> To unsubscribe, e-mail:users-unsubscr...@tomcat.apache.org > >>>> For additional commands, e-mail:users-h...@tomcat.apache.org > >>>> > >>>> > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > >
