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Re: Logging problem

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On 3/8/2012 8:53 PM, Novice wrote:
> As I started composing a reply to one one of the responders in the
> thread, it occurred to me that I really wasn't clear on what was SUPPOSED
> to happen with a normal log file. I had gotten as far as determining that
> getTail() in XMLFormatter would write the missing</log>  tag but I hadn't
> really thought through what SHOULD be happening. It occurred to me that
> maybe the aberrant behavior was what I _had_ been getting and maybe what
> I'm seeing now actually makes sense.
>
> Now that I've read and googled a bit more, I'm thinking I was right about
> that theory, although I'm definitely not certain. But in case I'm going
> down the wrong path, let me think out loud for a minute and you folks can
> tell me if I'm out in left field or if I'm making sense.
>
> After some poking around, I found close() and flush() methods in Handler,
> which is abstract, and in its children and grandchildren. The one that
> concerns me is FileHandler, which is the one that writes physical logs.
> Also, java.util.logging.Formatter, which is abstract, and its descendants
> have a getTail() method, which is what writes that missing</log>  record.
>
> It seems to me that a real log, one you'd see in a production system,
> would want to execute flush() and close() and getTail() when it was about
> to be closed. But what events would cause that? I went back to the
> logging.properties file and rediscovered
> java.util.logging.FileHandler.limit, which has a default value of 50,000.
> I'll assume that's lines but it may be the number of log records too; it
> doesn't much matter. I'm assuming that's how big a physical log file can
> get before it needs to be closed and a new file created. In the meantime,
> Java keeps writing log records to that log. The mere fact that I start or
> stop a given program shouldn't have any effect on whether the log is
> locked or not; the log will be available when it's needed and will get
> written until it is full.
>
> Now, what happens when it gets full? Well, if it is a continuous log, we
> just keep creating new physical law files, typically with a sequential
> number to distinguish it from earlier logs, e.g. log0, log1, log2, etc.
> The integer just keeps going up. If it is a circular log, we keep
> incrementing the integer until we hit a threshhold like 5 or 10, then
> start back at 0, overwriting the old log0. If I remember correctly, Java
> can do both continuous or circular logs.
>
> Have I got this more-or-less right so far? Because that would make sense
> to me based on my (somewhat vague) memories of logging in relational
> databases.
>
> If I do have that right, then the aberrant behavior was when the log was
> nicely closed as soon as my program ended. (Which raises the question why
> did THAT happen? But if I'm right about the log not normally getting the
> </log>  tag added until the log is closed because it's full, then I'm not
> going to worry about the aberrant behavior. I just want to know how to
> work with a log that is functioning normally.)
>
> So, if a log normally only gets that</log>  tag written when it is ready
> to be closed because it's full, what happens in the real world if you
> want to read a log BEFORE it's full? If there is some kind of system
> crash long before the log is full, you're not going to want to wait until
> the log is full; you want to read it NOW. So how what do you do? That has
> to be a routine situation and there must be a routine answer. And that's
> as far as I've gotten with my reasoning.
>
> If I'm right, nothing is really broken after all and I was just finding
> those log files closed and finished by sheer good luck (or having done
> some stupid things that worked in my favor). In that case, I just need to
> know how the rest of you arrange to read an incomplete log. Maybe there's
> a standard utility that you use to read an incomplete log??
>
> I'll stop there and wait for your feedback before I go off the rails
> completely ;-)

I still believe that your best option will be to use a non
XML format.

The second best option must be to have a little FixEndTag
utility ready to be used.

Arne

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Thread

Logging problem Novice <novice@example..com> - 2012-03-08 19:38 +0000
  Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 14:48 -0500
    Re: Logging problem Novice <novice@example..com> - 2012-03-08 20:06 +0000
      Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 15:38 -0500
        Re: Logging problem Martin Gregorie <martin@address-in-sig.invalid> - 2012-03-08 22:02 +0000
      Re: Logging problem Patricia Shanahan <pats@acm.org> - 2012-03-08 14:53 -0800
        Re: Logging problem markspace <-@.> - 2012-03-08 15:20 -0800
          Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 19:48 -0500
            Re: Logging problem Patricia Shanahan <pats@acm.org> - 2012-03-08 17:17 -0800
              Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 20:55 -0500
                Re: Logging problem markspace <-@.> - 2012-03-08 18:01 -0800
                Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 21:19 -0500
      Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 20:56 -0500
  Re: Logging problem markspace <-@.> - 2012-03-08 14:18 -0800
    Re: Logging problem Novice <novice@example..com> - 2012-03-09 01:53 +0000
      Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 20:59 -0500
      Re: Logging problem Novice <novice@example..com> - 2012-03-09 05:36 +0000
        Re: Logging problem Patricia Shanahan <pats@acm.org> - 2012-03-09 06:27 -0800
        Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-09 12:31 -0500
          Re: Logging problem Novice <novice@example..com> - 2012-03-09 18:57 +0000
            Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-09 14:26 -0500
        Re: Logging problem Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-03-09 15:59 -0400
          Re: Logging problem Novice <novice@example..com> - 2012-03-09 21:32 +0000
            Re: Logging problem Lew <lewbloch@gmail.com> - 2012-03-09 13:56 -0800
              Re: Logging problem Novice <novice@example..com> - 2012-03-09 22:57 +0000
                Re: Logging problem Martin Gregorie <martin@address-in-sig.invalid> - 2012-03-10 14:51 +0000
                Re: Logging problem Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-03-10 13:00 -0400
                Re: Logging problem Lew <noone@lewscanon.com> - 2012-03-10 10:04 -0800
                Re: Logging problem Martin Gregorie <martin@address-in-sig.invalid> - 2012-03-10 20:23 +0000
                Re: Logging problem Lew <noone@lewscanon.com> - 2012-03-10 07:56 -0800
                Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-10 12:05 -0500
                Re: Logging problem Lew <noone@lewscanon.com> - 2012-03-10 10:10 -0800
                Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-12 16:13 -0400
                Re: Logging problem Novice <novice@example..com> - 2012-03-10 20:10 +0000
            Re: Logging problem Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-03-09 19:15 -0400
              Re: Logging problem Novice <novice@example..com> - 2012-03-10 01:59 +0000

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