On Oct 19, 2008, at 3:12 PM, Peter Steele wrote:
We've noticed somewhat undersirable logging behavior when we change the time zone our appllicaton is running under. When the application starts,the timestamps used in our log files match the current local time, albeit without an explicit time zone identifier included in the time,but that's okay. However, if we change the time zone, e.g. from 8:00 amPDT to 8:00 am EDT, while the local time simply starts displaying the new time zone identifier, the log timestamps get shifted by thedifference in the time zones. In this specific case, the log timestampswould get shifted to 5:00 am.
If we then stop and restart the application, the timestamps are thenbased again on the local time (8:00 am instead of 5:00 am). This is whatwe want of course, but we want this to happen dynamically as well and not have to restart the application to get the timestamps in sync with the local time. How can we accomplish this? We want the timestamps to match whatever the local time is, regardless of the time zone, even after a time zone change. Is there a logger call we can make?
If you are changing from 8:00 AM PDT to 8:00 AM EDT, you are not just changing the time zone, but you are also changing the time. If you are using a timestamp (milliseconds since the epoch), then they value would change when you changed the time though it should not be affected if you just changed the timezone.
Are you changing the timezone using a operating system utility (control panel etc) or by using a call to TimeZone.setDefault()? Different JVM's may have different approaches to how a change in the operating system timezone becomes visible in the JDK. If the JDK only checks the default timezone at start up, there is nothing log4j can do. Knowing the vendor and version of the OS and JVM in use and the exact method of making the timezone change would be helpful to understand your observed behavior. It does appear that you are seeing an immediate effect from changing the time, but the timezone is not immediately updated in the app by the manner you are making the change.
I'd suggest using the EnhancedPatternLayout in the extras companion and output the time in a fixed timezone. Something like:
%d{yyyy-MM-dd HH:mm:ss}{UTC}Z - %c - %m%n
You could also output the time in local time for convenience, but
you'd always have the time in a known timezone.
--------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
