Craig,
Thanks again for the response.
My understanding from ur reply,
As I am using the log() function provided by the API, the effect could
perhaps relate to the way JRUN implements the logging on a Windows NT
machine. Jrun , I notice, usually writes logging into a "event.log" ascii
file.
I am not doing too much of logging, my concern is due to the number of hits
on the servlet itself.
Cheers
Ramesh.V
> -----Original Message-----
> From: A mailing list for discussion about Sun Microsystem's Java Servlet
> API Technology. [mailto:[EMAIL PROTECTED]]On Behalf Of Craig
> McClanahan
> Sent: Monday, August 09, 1999 12:24 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Does logging affect servlet synchronization.
>
>
> Ramesh Venkatraman wrote:
>
> > Hi Folks,
> >
> > I have a query here,
> >
> > Assuming we have a servlet which incorporates multi-threading
> (i.e it does
> > not use any thread synchronization) and now assuming there is a
> call to the
> > method "log()" somewhere in the servlet. Will this simple method log()
> > actually make the servlet to run in a synchronised way?
> > The reason being.
> >
> > a) The log() method writes the String into a text file. A text file, me
> > thinks, unlike an RDBMS table can be written in a sycnhronized
> manner and
> > not concurrently. (I am using Jrun on IIS.)
> >
> > b) Or will the servlet engine queue the messages to be written
> one by one.
> >
> > c) Will the effect be the same for System.out.println() and
> > System.err.println().
> >
> > Am I missing something very simple here :-).
> >
>
> In principle, at least three factors in the implementation affect how much
> overhead there is:
>
> * Does the log() implementation write directly to an underlying file,
> or does it just queue messages to an in-memory buffer that is
> flushed asynchronously by a background thread?.
>
> * Does the underlying log stream buffer its output? If so, you would
> only run into contention at log flush times, not during buffering.
>
> * Does the OS deal efficiently with multithreaded access to a single
> underlying file? Unix-based systems are, in general, very good at
> this, even across multiple processes.
>
> In practice, you have to be logging an awful lot of stuff before
> synchronization
> on the log would have any appreciable impact. I would not worry
> too much about
> this issue (unless, of course, you run a profiler on your servlet
> engine and
> find out that it really is an issue :-).
>
> Similar issues apply to System.out, which is usually buffered by the JVM.
> System.err is usually unbuffered, because you normally want your
> error messages
> visible as quickly as possible.
>
> >
> > Thanx in advance for any answers
> >
>
> No problem.
>
> Craig McClanahan
>
>
> >
> > Cheers
> > Ramesh
> >
> >
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