Struct parquet::basic::GzipLevel

pub struct GzipLevel(/* private fields */);

Represents a valid gzip compression level.

Defaults to 6.

• 0: least compression
• 9: most compression (that other software can read)
• 10: most compression (incompatible with other software, see below)

WARNING:

Level 10 compression can offer smallest file size, but Parquet files created with it will not be readable by other “standard” paquet readers.

Do NOT use level 10 if you need other software to be able to read the files. Read below for details.

IMPORTANT:

There’s often confusion about the compression levels in flate2 vs arrow as highlighted in issue #1011.

flate2 supports two compression backends: miniz_oxide and zlib.

• zlib supports levels from 0 to 9.
• miniz_oxide supports levels from 0 to 10.

arrow uses flate with rust_backend feature, which provides miniz_oxide as the backend. Therefore 0-10 levels are supported.

flate2 documents this behavior properly with this commit.

Implementations

impl GzipLevel

pub fn try_new(level: u32) -> Result<Self>

Attempts to create a gzip compression level.

Compression levels must be valid (i.e. be acceptable for flate2::Compression).

pub fn compression_level(&self) -> u32

Returns the compression level.

Trait Implementations

impl Clone for GzipLevel

fn clone(&self) -> GzipLevel

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for GzipLevel

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

Formats the value using the given formatter.

impl Default for GzipLevel

fn default() -> Self

Returns the “default value” for a type.

impl Hash for GzipLevel

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, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for GzipLevel

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

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for GzipLevel

impl Eq for GzipLevel

impl StructuralPartialEq for GzipLevel