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PARQUET-2414: Extend BYTE_STREAM_SPLIT to support INT32, INT64 and FI…
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…XED_LEN_BYTE_ARRAY data (#229)
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pitrou authored Mar 18, 2024
1 parent 38f79c9 commit e517ac4
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6 changes: 6 additions & 0 deletions CHANGES.md
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# Parquet #

### Version 2.11.0 ###

#### New Feature

* [PARQUET-2414](https://issues.apache.org/jira/browse/PARQUET-2414) - Extend BYTE_STREAM_SPLIT to support INT32, INT64 and FIXED_LEN_BYTE_ARRAY data

### Version 2.10.0 ###

#### New Feature
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5 changes: 3 additions & 2 deletions Encodings.md
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### Byte Stream Split: (BYTE_STREAM_SPLIT = 9)

Supported Types: FLOAT, DOUBLE
Supported Types: FLOAT, DOUBLE, INT32, INT64, FIXED_LEN_BYTE_ARRAY

This encoding does not reduce the size of the data but can lead to a significantly better
compression ratio and speed when a compression algorithm is used afterwards.

This encoding creates K byte-streams of length N where K is the size in bytes of the data
type and N is the number of elements in the data sequence. Specifically, K is 4 for FLOAT
type and N is the number of elements in the data sequence. For example, K is 4 for FLOAT
type and 8 for DOUBLE type.

The bytes of each value are scattered to the corresponding streams. The 0-th byte goes to the
0-th stream, the 1-st byte goes to the 1-st stream and so on.
The streams are concatenated in the following order: 0-th stream, 1-st stream, etc.
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7 changes: 5 additions & 2 deletions src/main/thrift/parquet.thrift
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*/
RLE_DICTIONARY = 8;

/** Encoding for floating-point data.
/** Encoding for fixed-width data (FLOAT, DOUBLE, INT32, INT64, FIXED_LEN_BYTE_ARRAY).
K byte-streams are created where K is the size in bytes of the data type.
The individual bytes of an FP value are scattered to the corresponding stream and
The individual bytes of a value are scattered to the corresponding stream and
the streams are concatenated.
This itself does not reduce the size of the data but can lead to better compression
afterwards.
Added in 2.8 for FLOAT and DOUBLE.
Support for INT32, INT64 and FIXED_LEN_BYTE_ARRAY added in 2.11.
*/
BYTE_STREAM_SPLIT = 9;
}
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