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Thread-Topic: Why hadoop is spawing two map over file size 1.5 KB ?
Thread-Index: AQHOHw2i0dIk5Ta1IUar0KlbMJmwcJikyE4AgACUehk=
Date: Thu, 14 Mar 2013 16:04:48 +0000
Message-ID: <F967A64B0462AA4CA247F86ED78A151F014897B5@EX2.corp.qihoo.net>
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<div style=3D"direction: ltr;font-family: Tahoma;color: #000000;font-size: =
10pt;">please check parameter &quot;mapred.map.tasks&quot; is equals to 2?<=
br>
<div style=3D"font-family: Times New Roman; color: #000000; font-size: 16px=
">
<hr tabindex=3D"-1">
<div id=3D"divRpF771449" style=3D"direction: ltr; "><font face=3D"Tahoma" s=
ize=3D"2" color=3D"#000000"><b>=B7=A2=BC=FE=C8=CB:</b> Yanbo Liang [yanboha=
ppy@gmail.com]<br>
<b>=B7=A2=CB=CD=CA=B1=BC=E4:</b> 2013=C4=EA3=D4=C214=C8=D5 23:11<br>
<b>=CA=D5=BC=FE=C8=CB:</b> user@hadoop.apache.org<br>
<b>=D6=F7=CC=E2:</b> Re: Why hadoop is spawing two map over file size 1.5 K=
B ?<br>
</font><br>
</div>
<div></div>
<div>I guess may be one of them is the speculative execution.
<div>You can check the parameter &quot;<span style=3D"color:rgb(51,51,51); =
font-family:Helvetica,Tahoma,Arial,sans-serif; line-height:24px; background=
-color:rgb(245,245,245)">mapred.map.tasks.speculative.execution&quot; to en=
sure whether it is allowed speculative execution.&nbsp;</span></div>
<div><font color=3D"#333333" face=3D"Helvetica, Tahoma, Arial, sans-serif">=
<span style=3D"line-height:24px">You can get the precise information that w=
hether it is speculative map task from the tasktracker log.<br>
</span></font><br>
<div class=3D"gmail_quote">2013/3/12 samir das mohapatra <span dir=3D"ltr">=
&lt;<a href=3D"mailto:samir.helpdoc@gmail.com" target=3D"_blank">samir.help=
doc@gmail.com</a>&gt;</span><br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex; border-left:1=
px #ccc solid; padding-left:1ex">
<div dir=3D"ltr">
<div>
<div>Hi All,<br>
</div>
&nbsp; I have very fundamental doubt, I have file having size 1.5KB and blo=
ck size is default block size, But i could see two mapper it got creted dur=
ing the Job. Could you please help&nbsp; to get whole picture why it is .<b=
r>
<br>
</div>
Regards,<br>
samir.<br>
</div>
</blockquote>
</div>
<br>
</div>
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