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Re: Logging problem

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Arved Sandstrom <asandstrom3minus1@eastlink.ca> wrote in
news:Mit6r.5211$v11.1861@newsfe20.iad: 

> On 12-03-09 01:36 AM, Novice wrote:
> [ SNIP ]
>> 
>> It would be very helpful if someone could explain what would happen
>> in a real-world production situation where a long-running batch
>> program or a constantly-running online program started writing error
>> messages to the log. What will operators do to be able to read the
>> log? I'm guessing they force it to close early and then start a new
>> file or they have a tool that will read the log file correctly even
>> without the final </log> tag. 
>> 
> In a real-world production situation odds are you're getting errors
> logged all the time. There are a whole bunch of errors that will
> happen, sometimes frequently, sometimes a few times a day, sometimes
> once a month, but you know they _will_ happen. So routine errors get
> logged all the time.
> 
I'm a little surprised by that. I would have thought actual errors would 
get acted on fairly quickly, particulary anything categorized as SEVERE. 
(I'll use the java.util.logging levels for these remarks.) I could see 
that something that is categorized as WARNING may take longer to fix, 
especially if WARNING is used for messages that indicate the program is 
able to continue using some kind of alternate strategy; if the alternate 
strategy is perfectly reasonable and doesn't skew the result, there's no 
great harm in leaving the problem unsolved. But if we assume that a 
SEVERE error is a show-stopper, wouldn't that get dealt with right away?

> As for how do ops support folks read ongoing stuff? Well, surely you
> must have used 'tail', 

I haven't worked on Unix/Linux in a while but I have used 'tail' ;-) 
Frankly, I don't recall if it works on open files but from you've said, 
apparently it does. 

> or perhaps opened up a decent programming text
> editor on a file that's being currently written to, or even just
> looked at console output. Apart from some buffering going on (none,
> line or block), which really only determines if you see your stuff
> immediately, very quickly or just quickly, fact is that what you're
> logging shows up in your log file rapidly, and then you can read it -
> there's no need to close the file.
> 
Perfect. Existing tools that will read the file while still being written 
are what I was hoping for ;-) 

> As Arne mentioned, a file will get closed when the log file is rolled
> over for size and/or time, or because the entire application stopped.
> But that's a different matter.
>
Indeed.
 
> I've worked with several app servers that routinely log some files as
> XML; I can't say it's ever occurred to me to take a peek at the XML as
> text and see what state it's in during ongoing writing. These are
> server logs, not application logs, so I don't usually have reason to.
> 
> I'm with Arne on not using XML logs yourself. There's no need for it.
> Out in the wide world users of logs will thank you for not using XML.
> 
You and Arne and Patricia have convinced me. XML isn't the way to go 
after all, especially if it necessitates changing the way things get done 
- such as when logs get closed - or writing new tools to be able to read 
incomplete files just to be able to read XML logs. That means I can 
remove the code that closes the handler from my program which strikes me 
as a a good thing ;-)

Well, this little mishap with the XML logs has been a good thing overall 
in that it's steered me away from a problematic approach and back towards 
something that follows established practice. 

Thanks to everyone who contributed to the thread.
-- 
Novice

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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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