Trait lance_encoding::EncodingsIo

pub trait EncodingsIo: Send + Sync {
    // Required method
    fn submit_request(
        &self,
        range: Vec<Range<u64>>,
        priority: u64,
    ) -> BoxFuture<'static, Result<Vec<Bytes>>>;

    // Provided method
    fn submit_single(
        &self,
        range: Range<u64>,
        priority: u64,
    ) -> BoxFuture<'static, Result<Bytes>> { ... }
}

A trait for an I/O service

This represents the I/O API that the encoders and decoders need in order to operate. We specify this as a trait so that lance-encodings does not need to depend on lance-io

In general, it is assumed that this trait will be implemented by some kind of “file reader” or “file scheduler”. The encodings here are all limited to accessing a single file.

Required Methods

fn submit_request( &self, range: Vec<Range<u64>>, priority: u64, ) -> BoxFuture<'static, Result<Vec<Bytes>>>

Submit an I/O request

The response must contain a Bytes object for each range requested even if the underlying I/O was coalesced into fewer actual requests.

Arguments

• ranges - the byte ranges to request
• priority - the priority of the request

Priority should be set to the lowest row number that this request is delivering data for. This is important in cases where indirect I/O causes high priority requests to be submitted after low priority requests. We want to fulfill the indirect I/O more quickly so that we can decode as quickly as possible.

Provided Methods

fn submit_single( &self, range: Range<u64>, priority: u64, ) -> BoxFuture<'static, Result<Bytes>>

Submit an I/O request with a single range

This is just a utitliy function that wraps EncodingsIo::submit_request for the common case of a single range request.

Implementors

impl EncodingsIo for BufferScheduler