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Posted to common-commits@hadoop.apache.org by Apache Wiki <wi...@apache.org> on 2010/07/15 00:21:19 UTC

[Hadoop Wiki] Update of "Hive/LanguageManual/DDL/BucketedTables" by PaulYang

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The "Hive/LanguageManual/DDL/BucketedTables" page has been changed by PaulYang.
http://wiki.apache.org/hadoop/Hive/LanguageManual/DDL/BucketedTables?action=diff&rev1=9&rev2=10

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- This is a brief example on creating a populating bucketed tables.  Bucketed tables are fantastic in that they allow much more efficient sampling than do non-bucketed tables, and they may later allow for time saving operations such as mapside joins.  However, the bucketing specified at table creation is not enforced when the table is written to, and so it is possible for the table's metadata to advertise properties which are not upheld by the table's actual layout.  This should obviously be avoided.  Here's how to do it right.
+ This is a brief example on creating and populating bucketed tables.  Bucketed tables are fantastic in that they allow much more efficient sampling than do non-bucketed tables, and they may later allow for time saving operations such as mapside joins.  However, the bucketing specified at table creation is not enforced when the table is written to, and so it is possible for the table's metadata to advertise properties which are not upheld by the table's actual layout.  This should obviously be avoided.  Here's how to do it right.
  
  First there’s table creation:
  {{{