Enum parquet::basic::Encoding

pub enum Encoding {
    PLAIN,
    PLAIN_DICTIONARY,
    RLE,
    BIT_PACKED,
    DELTA_BINARY_PACKED,
    DELTA_LENGTH_BYTE_ARRAY,
    DELTA_BYTE_ARRAY,
    RLE_DICTIONARY,
}

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.

Variants

PLAIN

Default byte encoding.

• 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, stored as little-endian.
• DOUBLE - 8 bytes per value, stored as little-endian.
• BYTE_ARRAY - 4 byte length stored as little endian, followed by bytes.
• FIXED_LEN_BYTE_ARRAY - just the bytes are stored.

PLAIN_DICTIONARY

Deprecated dictionary encoding.

The values in the dictionary are encoded using PLAIN encoding. Since it is deprecated, RLE_DICTIONARY encoding is used for a data page, and PLAIN encoding is used for dictionary page.

RLE

Group packed run length encoding.

Usable for definition/repetition levels encoding and boolean values.

BIT_PACKED

Bit packed encoding.

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

DELTA_BINARY_PACKED

Delta encoding for integers, either INT32 or INT64.

Works best on sorted data.

DELTA_LENGTH_BYTE_ARRAY

Encoding for byte arrays to separate the length values and the data.

The lengths are encoded using DELTA_BINARY_PACKED encoding.

DELTA_BYTE_ARRAY

Incremental encoding for byte arrays.

Prefix lengths are encoded using DELTA_BINARY_PACKED encoding. Suffixes are stored using DELTA_LENGTH_BYTE_ARRAY encoding.

RLE_DICTIONARY

Dictionary encoding.

The ids are encoded using the RLE encoding.

Trait Implementations

impl Clone for Encoding

fn clone(&self) -> Encoding

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl From<Encoding> for Encoding

fn from(value: Encoding) -> Self

Performs the conversion.

impl From<Encoding> for Encoding

fn from(value: Encoding) -> Self

Performs the conversion.

impl Eq for Encoding

impl Copy for Encoding

impl PartialEq<Encoding> for Encoding

fn eq(&self, other: &Encoding) -> bool

This method tests for self and other values to be equal, and is used by ==.

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl Display for Encoding

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Debug for Encoding

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Hash for Encoding

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given [Hasher].

fn hash_slice<H>(data: &[Self], state: &mut H) where     H: Hasher,

Feeds a slice of this type into the given [Hasher].