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- INSERT OVERWRITE statements to directories, local directories and tables (or partitions) can all be used together within the same query.
- INSERT OVERWRITE statements to HDFS filesystem directories is the best way to extract large amounts of data from Hive. Hive can write to HDFS directories in parallel from within a map-reduce job.
- The directory is, as you would expect, OVERWRITten, in other words, if the specified path exists, it is clobbered and replaced with the output.
Truncating tables
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As of Hive 0.10.0 (HIVE-446) |
Syntax
Code Block |
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TRUNCATE TABLE table_name [PARTITION partition_spec];
partition_spec:
: (partition_col = partition_col_value, partition_col = partiton_col_value, ...)
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Synopsis
- Removes all rows from a table or partition(s).
- Table should be native/managed table (or exception will be thrown).
Notes
- User can specify partial partition spec for truncating multiple partitions at once.
- Without partition spec, all partitions in the table will be truncated.