Hi Subroto, Thank you very much! 2011-08-08
tanjun_2525 发件人: Subroto Sanyal <subrotosan...@huawei.com> 发送时间: 2011-08-08 12:33 主 题: RE: How can I know how many mappers created? 收件人: mapreduce-user@hadoop.apache.org Hi Jun, Request you to go through this link: http://wiki.apache.org/hadoop/HowManyMapsAndReduces Following configuration may help you : mapred.min.split.size mapred.map.tasks (This is just a hint to InputFormat) But how can I know how many mappers have been created while doing my job? The implementation of InputFormat actually defines how many Mappers are going to be in the submitted job. Can I do some sets to make it only 2 mappers created and each mapper runs on one node? The scheduler implementation has the logic to schedule mappers and reducers. Regards, Subroto Sanyal From: 谭军 [mailto:tanjun_2...@163.com] Sent: Sunday, August 07, 2011 12:15 PM To: mapreduce-user@hadoop.apache.org Subject: How can I know how many mappers created? Hi, I just want 2 mappers created to do my job for there are only 2 data nodes. I think that is the most efficient. But how can I know how many mappers have been created while doing my job? Can I do some sets to make it only 2 mappers created and each mapper runs on one node? Thanks -- Best regards! Jun Tan