Struct ZoneMaps

pub struct ZoneMaps {
    pub rows_per_map: u32,
    pub stats: Option<ArrayEncoding>,
    pub values: Option<ArrayEncoding>,
}

ZoneMaps are a way to wrap any leaf array with a set of zone maps that can be used to apply pushdown filtering.

A “zone map” is the min/max/null_count of a set of rows. This can be used to quickly filter out zones which are not included in simple predicates like ‘x = 5’ or ‘x > 10’.

Fields

rows_per_map: u32

How many rows are covered by each zone map. There will be ceil_div(num_rows, rows_per_map) zone maps.

stats: Option<ArrayEncoding>

The zone maps are encoded as struct arrays with 1 row per zone. This should be stored in a column metadata buffer. The struct array should have 3 children: min: T, max: T, null_count: u32

values: Option<ArrayEncoding>

The underlying array values

Trait Implementations

impl Clone for ZoneMaps

fn clone(&self) -> ZoneMaps

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ZoneMaps

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

Formats the value using the given formatter.

impl Default for ZoneMaps

fn default() -> Self

Returns the “default value” for a type.

impl Message for ZoneMaps

fn encoded_len(&self) -> usize

Returns the encoded length of the message without a length delimiter.

fn clear(&mut self)

Clears the message, resetting all fields to their default.

fn encode<B>(&self, buf: &mut B) -> Result<(), EncodeError>

where B: BufMut, Self: Sized,

Encodes the message to a buffer.

fn encode_to_vec(&self) -> Vec<u8>

where Self: Sized,

Encodes the message to a newly allocated buffer.

fn encode_length_delimited<B>(&self, buf: &mut B) -> Result<(), EncodeError>

where B: BufMut, Self: Sized,

Encodes the message with a length-delimiter to a buffer.

fn encode_length_delimited_to_vec(&self) -> Vec<u8>

where Self: Sized,

Encodes the message with a length-delimiter to a newly allocated buffer.

fn decode<B>(buf: B) -> Result<Self, DecodeError>

where B: Buf, Self: Default,

Decodes an instance of the message from a buffer.

fn decode_length_delimited<B>(buf: B) -> Result<Self, DecodeError>

where B: Buf, Self: Default,

Decodes a length-delimited instance of the message from the buffer.

fn merge<B>(&mut self, buf: B) -> Result<(), DecodeError>

where B: Buf, Self: Sized,

Decodes an instance of the message from a buffer, and merges it into self.

fn merge_length_delimited<B>(&mut self, buf: B) -> Result<(), DecodeError>

where B: Buf, Self: Sized,

Decodes a length-delimited instance of the message from buffer, and merges it into self.

impl Name for ZoneMaps

const NAME: &'static str = "ZoneMaps"

Simple name for this Message. This name is the same as it appears in the source .proto file, e.g. FooBar.

const PACKAGE: &'static str = "lance.encodings_datafusion"

Package name this message type is contained in. They are domain-like and delimited by ., e.g. google.protobuf.

fn full_name() -> String

Fully-qualified unique name for this Message. It’s prefixed with the package name and names of any parent messages, e.g. google.rpc.BadRequest.FieldViolation. By default, this is the package name followed by the message name. Fully-qualified names must be unique within a domain of Type URLs.

fn type_url() -> String

Type URL for this Message, which by default is the full name with a leading slash, but may also include a leading domain name, e.g. type.googleapis.com/google.profile.Person. This can be used when serializing with the [Any] type.

impl PartialEq for ZoneMaps

fn eq(&self, other: &ZoneMaps) -> 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 StructuralPartialEq for ZoneMaps