Flow PHP

Encoding

FinalYes

Encodings supported by Parquet. Not all encodings are valid for all types. These enums are also used to specify the encoding of definition and repetition levels.

See the accompanying doc for the details of the more complicated encodings.

Constants

ALP : mixed = 10: Adaptive Lossless floating-Point (ALP) encoding for FLOAT and DOUBLE.
BIT_PACKED : mixed = 4: DEPRECATED: Bit packed encoding. This can only be used if the data has a known max width. Usable for definition/repetition levels encoding.
BYTE_STREAM_SPLIT : mixed = 9: Encoding for fixed-width data (FLOAT, DOUBLE, INT32, INT64, FIXED_LEN_BYTE_ARRAY).
DELTA_BINARY_PACKED : mixed = 5: Delta encoding for integers. This can be used for int columns and works best on sorted data
DELTA_BYTE_ARRAY : mixed = 7: Incremental-encoded byte array. Prefix lengths are encoded using DELTA_BINARY_PACKED.
DELTA_LENGTH_BYTE_ARRAY : mixed = 6: Encoding for byte arrays to separate the length values and the data. The lengths are encoded using DELTA_BINARY_PACKED
PLAIN : mixed = 0: Default encoding.
PLAIN_DICTIONARY : mixed = 2: DEPRECATED: Dictionary encoding. The values in the dictionary are encoded in the plain type.
RLE : mixed = 3: Group packed run length encoding. Usable for definition/repetition levels encoding and Booleans (on one bit: 0 is false; 1 is true.)
RLE_DICTIONARY : mixed = 8: Dictionary encoding: the ids are encoded using the RLE encoding

Properties

$__names : mixed

ALP

Adaptive Lossless floating-Point (ALP) encoding for FLOAT and DOUBLE.


    public
        mixed
    ALP
    = 10

Losslessly converts decimal-like floating-point values to integers via decimal scaling, then applies Frame of Reference (FOR) encoding and bit-packing; values that cannot be converted losslessly are stored as exceptions. See Encodings.md for the detailed specification.

BIT_PACKED

DEPRECATED: Bit packed encoding. This can only be used if the data has a known max width. Usable for definition/repetition levels encoding.


    public
        mixed
    BIT_PACKED
    = 4

Superseded by RLE (which is a hybrid of RLE and bit packing); see Encodings.md.

BYTE_STREAM_SPLIT

Encoding for fixed-width data (FLOAT, DOUBLE, INT32, INT64, FIXED_LEN_BYTE_ARRAY).


    public
        mixed
    BYTE_STREAM_SPLIT
    = 9

K byte-streams are created where K is the size in bytes of the data type. 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.

DELTA_BINARY_PACKED

Delta encoding for integers. This can be used for int columns and works best on sorted data


    public
        mixed
    DELTA_BINARY_PACKED
    = 5

DELTA_BYTE_ARRAY

Incremental-encoded byte array. Prefix lengths are encoded using DELTA_BINARY_PACKED.


    public
        mixed
    DELTA_BYTE_ARRAY
    = 7

Suffixes are stored as delta length byte arrays.

DELTA_LENGTH_BYTE_ARRAY

Encoding for byte arrays to separate the length values and the data. The lengths are encoded using DELTA_BINARY_PACKED


    public
        mixed
    DELTA_LENGTH_BYTE_ARRAY
    = 6

PLAIN

Default encoding.


    public
        mixed
    PLAIN
    = 0

BOOLEAN - 1 bit per value. 0 is false; 1 is true. INT32 - 4 bytes per value. Stored as little-endian. INT64 - 8 bytes per value. Stored as little-endian. FLOAT - 4 bytes per value. IEEE. Stored as little-endian. DOUBLE - 8 bytes per value. IEEE. Stored as little-endian. BYTE_ARRAY - 4 byte length stored as little endian, followed by bytes. FIXED_LEN_BYTE_ARRAY - Just the bytes.

PLAIN_DICTIONARY

DEPRECATED: Dictionary encoding. The values in the dictionary are encoded in the plain type.


    public
        mixed
    PLAIN_DICTIONARY
    = 2

For a data page use RLE_DICTIONARY instead. For a Dictionary page use PLAIN instead.

RLE

Group packed run length encoding. Usable for definition/repetition levels encoding and Booleans (on one bit: 0 is false; 1 is true.)


    public
        mixed
    RLE
    = 3

RLE_DICTIONARY

Dictionary encoding: the ids are encoded using the RLE encoding


    public
        mixed
    RLE_DICTIONARY
    = 8

$__names


        public
        static    mixed
    $__names
     = array(0 => 'PLAIN', 2 => 'PLAIN_DICTIONARY', 3 => 'RLE', 4 => 'BIT_PACKED', 5 => 'DELTA_BINARY_PACKED', 6 => 'DELTA_LENGTH_BYTE_ARRAY', 7 => 'DELTA_BYTE_ARRAY', 8 => 'RLE_DICTIONARY', 9 => 'BYTE_STREAM_SPLIT', 10 => 'ALP')