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Date: Fri, 15 Aug 2014 13:44:01 +0100
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Subject: Re: [DISCUSS] Switch to log4j 2
From: Steve Loughran <stevel@hortonworks.com>
To: "hdfs-dev@hadoop.apache.org" <hdfs-dev@hadoop.apache.org>
Cc: "yarn-dev@hadoop.apache.org" <yarn-dev@hadoop.apache.org>,
	"common-dev@hadoop.apache.org" <common-dev@hadoop.apache.org>
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moving to SLF4J as an API is independent =E2=80=94it's just a better API fo=
r
logging than commons-logging, was already a dependency and doesn't force
anyone to switch to a new log back end.


On 15 August 2014 03:34, Tsuyoshi OZAWA <ozawa.tsuyoshi@gmail.com> wrote:

> Hi,
>
> Steve has started discussion titled "use SLF4J APIs in new modules?"
> as a related topic.
>
> http://mail-archives.apache.org/mod_mbox/hadoop-common-dev/201404.mbox/%3=
CCA+4kjVv_9cMmTDQZCgZy-CHSLyB1WkGdUNXS7wrhesLwbuHJjQ@mail.gmail.com%3E
>
> It sounds good to me to use asynchronous logging when we log INFO. One
> concern is that asynchronous logging makes debugging difficult - I
> don't know log4j 2 well, but I suspect that ordering of logging can be
> changed even if WARN or  FATAL are logged with synchronous logger.
>
> Thanks,
> - Tsuyoshi
>
> On Thu, Aug 14, 2014 at 6:44 AM, Arpit Agarwal <aagarwal@hortonworks.com>
> wrote:
> > I don't recall whether this was discussed before.
> >
> > I often find our INFO logging to be too sparse for useful diagnosis. A
> high
> > performance logging framework will encourage us to log more.
> Specifically,
> > Asynchronous Loggers look interesting.
> > https://logging.apache.org/log4j/2.x/manual/async.html#Performance
> >
> > What does the community think of switching to log4j 2 in a Hadoop 2.x
> > release?
> >
> > --
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