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Hadoop, mail # user - Logging info in hadoop


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Re: Logging info in hadoop
steven zhuang 2010-04-06, 14:16
hi, Nachiket,
*          I think if you output something to stderr, you should be able to
find it in the .out log. *
*Just make sure you are checking the right .out log file, *
*you can do that by checking which tasktrackers are running you job from the
web UI.*
* *
* *
On Tue, Apr 6, 2010 at 6:56 PM, Nachiket Vaidya <[EMAIL PROTECTED]> wrote:

> I have the following doubts:
> 1. How to print log information in Hadoop. In the documentation, I have
> read
> that hadoop-<username>-<processname>-<machinename>.log contains logs. I
> have
> used
> Log log = LogFactory.getLog(FBEMMapper.class);
> and
> log.info(....);
>
> for printing into log, but I do not see any log information in log file. I
> have also used System.out.println() but these are also not getting printed
> in .log or .out file.
> Do we need to change some log level in hadoop?
> Do we need to enable logging for some class?
> which log4j.properties file we need to change?
>
> Firstly, am I doing right things for logging?
>
> Actually the problem is I have written my custom FileInputFormat
> and WritableComparable for my purpose. My program runs fine, but I do not
> see any output. That is why I need to print some log statement to debug the
> problem.
>
> Thank you.
>
>
> - Nachiket
>