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From "RPost" <rp0...@pacbell.net>
Subject Re: regarding derby.log being overwritten on startup. [was Re: [jira] Commented: (DERBY-515) Network Server should log server start and shutdown time to derby.log]
Date Sat, 20 Aug 2005 00:21:03 GMT
And yet, to paraphrase a recent comment, 'Machines like reading delimited
format but people (at least certain people) find it a bit horrific'.

When I read Rick Hillegas's comment ("I'd like to see us emit more
structured logs.") the first question that came to my mind was just how
structured, in terms of content, are the current log messages?

Is the log record based with each message being represented by one record?
If so, is each record composed of the same number of items? That is, is item
one always a date, item 2 a class (or process) name, etc.

If there is no consistent structure to the messages I don't see how it would
be helpful to wrap the messages components in XML tags.

If there are a different number of components in each message record and no
defined order to the components I also don't see how it would be useful to
'slurp this right into Excel, load into a database, etc.

Perhaps it would make sense, as a first step, to try to standardize the
writing of the logs so that the structure of each message or component is
more consistent. A standardized content would then lend itself to a
different format for possible automation.

Can any of you comment of the degree to which the current log messages are,
or are not, consistent or lend themselves to 'record' type of content with
each record having the same number of data items?








----- Original Message ----- 
From: "Danesh" <danesh.i@gmail.com>
To: "Derby Development" <derby-dev@db.apache.org>
Sent: Friday, August 19, 2005 3:05 PM
Subject: Re: regarding derby.log being overwritten on startup. [was Re:
[jira] Commented: (DERBY-515) Network Server should log server start and
shutdown time to derby.log]


> I agree with going the delimited format route. Having the database
> write out XML would probably impact preformance quite a bit. I also
> wonder what would happen if the database were to die (power failure or
> the like) and the XML file ended up invalid due to it missing those
> crucial few closing tags. To simplify things and satisfy both parties
> someone could write a log conversion tool i.e. DEL -> XML.
>
> ~Danesh
>
> On 8/19/05, David Van Couvering <David.Vancouvering@sun.com> wrote:
> > Please, God, no :).  Machines like reading XML but people (at least
> > certain people) find it a bit horrific.
> >
> > What I have seen done in the past is using a simple delimiter format,
e.g.
> >
> > |Fri Aug 19 14:06:31 PST
> > 2005|org.apache.derby.engine.impl.jdbc.EmbedConnection|Thread
> > 275|Invalid user, please try again| | |
> >
> > then you can write tools that slurp this right into Excel, load into a
> > database, etc.  We did this with an app I worked on at Sybase and it was
> > quite successful.
> >
> > David
> >
> > Rick Hillegas wrote:
> >
> > > At the risk of overloading this topic: While we're talking about
> > > improvements to our error logging, I'd like to see us emit more
> > > structured logs. This is one of the things that xml is actually good
> > > for. It would be pretty easy to turn our log records into xml entries.
> > > This would make it easy to write or use off-the-shelf tools for
> > > viewing the logs and for filtering signal out of the noise.
> > >
> > > Cheers,
> > > -Rick
> > >
> > > David Van Couvering wrote:
> > >
> > >> Well, the most common solution is log rotation.  On restart, you
> > >> rename the old log to derby.log.1 and then derby.log.2 and so on.
> > >> After <n> log files, you start over again at derby.log.1.
> > >> This is also useful for long-running systems so you don't run out of
> > >> disk space because of your error logs.  When the error log gets a
> > >> configurable X MBs, the system copies the log to derby.log.1,
> > >> derby.log.2, etc.,  and starts a fresh log.  After N log files it
> > >> starts back at 1 and overwrites the old log file.  Similar but
> > >> different from above, but both are great to reduce administrative
> > >> overhead for the user.
> > >>
> > >> David
> > >>
> > >> Sunitha Kambhampati wrote:
> > >>
> > >>> Øystein Grøvlen wrote:
> > >>>
> > >>>>>>>>> "KM" == Kathey Marsden <kmarsdenderby@sbcglobal.net>
writes:
> > >>>>>>>>>
> > >>>>>>>>
> > >>>>>>>>
> > >>>>>>>>
> > >>>>
> > >>>>    KM> Øystein Grøvlen (JIRA) wrote:
> > >>>>    >> [    >> This would be even more helpful if the
derby.log file
> > >>>> was not overwritten on the next startup.  (Probably a separate
issue).
> > >>>>    >>    >>    >>    KM> The derby.infolog.append
property is
> > >>>> helpful in this regard.
> > >>>>
> > >>>>    KM>
> > >>>> http://db.apache.org/derby/docs/10.1/tuning/rtunproper13217.html
> > >>>>
> > >>>> Thanks, Kathey, that is really what I need.
> > >>>>
> > >>>>
> > >>>>
> > >>> One concern I have is that by default, the derby.log gets
> > >>> overwritten on subsequent boot. From my experience with customers,
> > >>> whenever there is an issue, I always end up telling them to add this
> > >>> property almost every time to see the debug logs. It is very common
> > >>> to see users reboot the system if they hit an error and in this
> > >>> case, it is probable that important relevant information in the
> > >>> derby.log is lost because it gets overwritten ( ex - recovery issues
> > >>> , deadlock etc ).
> > >>>
> > >>> Maybe we could do something smart for derby.log , a balance between
> > >>> keeping history across boots and disk space taken by the derby.logs.
> > >>>
> > >>> Any comments ?
> > >>>
> > >>> Sunitha.
> > >>
> > >>
> > >>
> > >
> >
> >
> >
>


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