Struct arrow_flight::PollInfo

pub struct PollInfo {
    pub info: Option<FlightInfo>,
    pub flight_descriptor: Option<FlightDescriptor>,
    pub progress: Option<f64>,
    pub expiration_time: Option<Timestamp>,
}

The information to process a long-running query.

Fields

info: Option<FlightInfo>

The currently available results.

If “flight_descriptor” is not specified, the query is complete and “info” specifies all results. Otherwise, “info” contains partial query results.

Note that each PollInfo response contains a complete FlightInfo (not just the delta between the previous and current FlightInfo).

Subsequent PollInfo responses may only append new endpoints to info.

Clients can begin fetching results via DoGet(Ticket) with the ticket in the info before the query is completed. FlightInfo.ordered is also valid.

flight_descriptor: Option<FlightDescriptor>

The descriptor the client should use on the next try. If unset, the query is complete.

progress: Option<f64>

Query progress. If known, must be in [0.0, 1.0] but need not be monotonic or nondecreasing. If unknown, do not set.

expiration_time: Option<Timestamp>

Expiration time for this request. After this passes, the server might not accept the retry descriptor anymore (and the query may be cancelled). This may be updated on a call to PollFlightInfo.

Implementations

impl PollInfo

pub fn progress(&self) -> f64

Returns the value of progress, or the default value if progress is unset.

impl PollInfo

pub fn new() -> Self

Create a new, empty PollInfo, providing information for a long-running query

Example:

// Create a new PollInfo
let poll_info = PollInfo::new()
  .with_info(FlightInfo::new())
  .with_descriptor(FlightDescriptor::new_cmd("RUN QUERY"))
  .try_with_progress(0.5)
  .expect("progress should've been valid")
  .with_expiration_time(
    "1970-01-01".parse().expect("invalid timestamp")
  );

pub fn with_info(self, info: FlightInfo) -> Self

Add the current available results for the poll call as a FlightInfo

pub fn with_descriptor(self, flight_descriptor: FlightDescriptor) -> Self

Add a FlightDescriptor that the client should use for the next poll call, if the query is not yet complete

pub fn try_with_progress(self, progress: f64) -> Result<Self, ArrowError>

Set the query progress if known. Must be in the range [0.0, 1.0] else this will return an error

pub fn with_expiration_time(self, expiration_time: Timestamp) -> Self

Specify expiration time for this request

Trait Implementations

impl Clone for PollInfo

fn clone(&self) -> PollInfo

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for PollInfo

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

Formats the value using the given formatter.

impl Default for PollInfo

fn default() -> Self

Returns the “default value” for a type.

impl Display for PollInfo

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

Formats the value using the given formatter.

impl Message for PollInfo

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 PartialEq for PollInfo

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

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

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

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

impl StructuralPartialEq for PollInfo