Struct CopyInWriter 

pub struct CopyInWriter<'a> { /* private fields */ }

A writer for COPY IN operations.

This struct holds the connection lock while sending data to ensure exclusive access during the COPY operation.

Implementations

impl CopyInWriter<'_>

pub fn send(&mut self, data: &[u8]) -> Result<()>

Sends a chunk of COPY data.

The data should be in HyperBinary format. For best performance, batch multiple rows into larger chunks (e.g., 1-16 MB).

Errors

Returns Error (I/O) if the wire write of the CopyData frame fails.

pub fn flush(&mut self) -> Result<()>

Flushes any buffered data to the server.

Errors

Returns Error (I/O) if flushing the internal write buffer to the transport fails.

pub fn send_direct(&mut self, data: &[u8]) -> Result<()>

Sends COPY data directly to the stream without internal buffering.

This writes data directly to the TCP stream, letting the kernel handle buffering. More efficient for streaming large amounts of data. Call flush_stream() periodically to ensure data is sent.

Errors

Returns Error (I/O) if writing to the underlying stream fails.

pub fn flush_stream(&mut self) -> Result<()>

Flushes the TCP stream.

Use with send_direct() to periodically ensure data reaches the server.

Errors

Returns Error (I/O) if flushing the underlying transport fails.

pub fn reserve_buffer(&mut self, capacity: usize)

Reserves capacity in the write buffer to avoid reallocations.

Call this before bulk operations to pre-allocate buffer space.

pub fn finish(self) -> Result<u64>

Finishes the COPY operation successfully.

Returns the number of rows inserted.

Errors

• Returns Error (I/O) if writing CopyDone or flushing the transport fails.
• Returns Error (server) if the server reports a COPY-side failure (constraint violation, type coercion error, etc.) via an ErrorResponse after CopyDone.

pub fn cancel(self, reason: &str) -> Result<()>

Cancels the COPY operation.

All data sent so far will be discarded.

Errors

Returns Error (I/O) if writing the CopyFail frame or flushing the transport fails, or Error (server) if the server reports an unexpected status after the cancel.

Trait Implementations

impl<'a> Debug for CopyInWriter<'a>

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

Formats the value using the given formatter.