Struct ExaImport 

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

Available on crate feature etl only.

An ETL IMPORT worker.

The type implements AsyncWrite and is Send and Sync so it can be freely used for any data pipeline.

The only caveat is that you MUST call futures_util::AsyncWriteExt::close on each worker to finalize the import. A worker that is dropped without closing will cause the HTTP connection to be unexpectedly dropped and the IMPORT query will return an error.

Atomicity

IMPORT jobs are not atomic by themselves. If an error occurs during the data ingestion, some of the data might be already sent and written in the database. However, since IMPORT is fundamentally just a query, it can be transactional. Therefore, beginning a transaction and passing that to the ImportBuilder::build method will result in the import job needing to be explicitly committed:

use std::env;

use sqlx_exasol::{error::*, etl::*, *};

let pool = ExaPool::connect(&env::var("DATABASE_URL").unwrap()).await?;
let mut con = pool.acquire().await?;
let mut tx = con.begin().await?;

let (query_fut, writers) = ImportBuilder::new("SOME_TABLE", None)
    .build(&mut *tx)
    .await?;

// concurrently use the writers and await the query future

tx.commit().await?;

IMPORTANT

During IMPORT jobs Exasol will make a series of HTTP requests to the driver, one for each worker. An IMPORT query is considered successful by Exasol if at least one HTTP response from the driver contains data. This means at least one crate::connection::etl::ExaImport worker (regardless which) must write some data before being closed.

Trait Implementations

impl AsyncWrite for ExaImport

fn poll_write( self: Pin<&mut ExaImport>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize, Error>>

Attempt to write bytes from buf into the object.

fn poll_write_vectored( self: Pin<&mut ExaImport>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>

Attempt to write bytes from bufs into the object using vectored IO operations.

fn poll_flush( self: Pin<&mut ExaImport>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>

Attempt to flush the object, ensuring that any buffered data reach their destination.

fn poll_close( self: Pin<&mut ExaImport>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>

Attempt to close the object.

impl Debug for ExaImport

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

Formats the value using the given formatter.