hadoop-mapreduce-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Something Something <mailinglist...@gmail.com>
Subject Business logic in cleanup?
Date Thu, 17 Nov 2011 04:23:13 GMT
Is the idea of writing business logic in cleanup method of a Mapper good or
bad?  We think we can make our Mapper run faster if we keep accumulating
data in a HashMap in a Mapper, and later in the cleanup() method write it.

1)  Does Map/Reduce paradigm guarantee that cleanup will always be called
before the reducer starts?
2)  Is cleanup strictly for cleaning up unneeded resources?
3)  We understand that the HashMap can grow & that could cause memory
issues, but hypothetically let's say the memory requirements
were manageable.

Please let me know.  Thanks.

Mime
View raw message