Struct PlanHint 

pub struct PlanHint {
    pub hint: String,
}

Optimization hint that carries a planner directive as a string.

Attach this to any standard relation via register_optimization to convey planner choices without changing relation semantics.

Text Format

=== Plan
Root[result]
  Read[data => col:i64]
    + Opt:PlanHint[hint='use_index']

Fields

hint: String

Planner directive. The text format stores this as hint='...'.

Trait Implementations

impl Clone for PlanHint

fn clone(&self) -> PlanHint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PlanHint

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

Formats the value using the given formatter.

impl Default for PlanHint

fn default() -> Self

Returns the “default value” for a type.

impl Explainable for PlanHint

fn name() -> &'static str

Canonical textual name for this extension. This is what appears in Substrait text plans and how the registry identifies the type.

fn from_args(args: &ExtensionArgs) -> Result<Self, ExtensionError>

Parse extension arguments into this type

fn to_args(&self) -> Result<ExtensionArgs, ExtensionError>

Convert this type to extension arguments

impl Message for PlanHint

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(&self, buf: &mut impl BufMut) -> Result<(), EncodeError>

where 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( &self, buf: &mut impl BufMut, ) -> Result<(), EncodeError>

where 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(buf: impl Buf) -> Result<Self, DecodeError>

where Self: Default,

Decodes an instance of the message from a buffer.

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

where Self: Default,

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

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

where Self: Sized,

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

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

where Self: Sized,

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

impl Name for PlanHint

const PACKAGE: &'static str = "example"

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

const NAME: &'static str = "PlanHint"

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

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 into the google.protobuf.Any type.

impl PartialEq for PlanHint

fn eq(&self, other: &PlanHint) -> 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 PlanHint