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Package org.apache.datasketches.pig.hll

Pig UDFs for HLL sketches.

See: Description

Package org.apache.datasketches.pig.hll Description

Pig UDFs for HLL sketches. These UDFs can be used as a replacement of corresponding Theta sketch UDFs. Notice that intersections and A-not-B operations are not supported by the HLL sketch. Also notice a small difference in the output type of DataToSketch and UnionSketch: HLL sketch UDFs return DataByteArray (BYTEARRAY in Pig), but corresponding Theta sketch UDFs return a Tuple with single DataByteArray inside. This was a historical accident, and we are reluctant to break the compatibility with existing scripts. HLL sketch UDFs don't have to keep this compatibility. As a result, HLL sketch UDFs don't need flatten() around them to remove the Tuple, and internally they don't have to spend extra resources to wrap every output DataByteArray into a Tuple.
Author:
Alexander Saydakov
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