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From Amjad ALSHABANI <>
Subject Number of Mapper when reading from Cassandra
Date Fri, 28 Mar 2014 11:17:18 GMT
Hello All,
I have tow tables created in Hive, one  read the data immidiately from
Cassandra DB and the other takes the data from stored files (data already
exported in somewhow from the same Cassandra DB)

Both tables are identical (in data)
but when running the same request it gives me very different number of
mapper for each of them (P.S I m using the same hive config for both

*hive -e " select count(1) from keyring.cred"*

will take 2338 mapper and 1 reducer


*hive -e "select count(1) from keyring.cred_seq"*

will take just 151 mapper and 1 reducer

Any idea how to minimize this number, and where does this explosion in
mapper number come from??

any response will be appreciated :)



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