# Class NpgsqlRawCopyStream

Namespace
  Npgsql

Assembly
  Npgsql.dll

Provides an API for a raw binary COPY operation, a high-performance data import/export mechanism to a PostgreSQL table. Initiated by BeginRawBinaryCopy(string)

    public sealed class NpgsqlRawCopyStream : Stream, IDisposable, IAsyncDisposable

Inheritance
  object
  MarshalByRefObject
  Stream
  NpgsqlRawCopyStream

Implements
  IDisposable
  IAsyncDisposable

Inherited Members
  Stream.Null
  Stream.BeginRead(byte[], int, int, AsyncCallback, object)
  Stream.BeginWrite(byte[], int, int, AsyncCallback, object)
  Stream.Close()
  Stream.CopyTo(Stream)
  Stream.CopyTo(Stream, int)
  Stream.CopyToAsync(Stream)
  Stream.CopyToAsync(Stream, int)
  Stream.CopyToAsync(Stream, int, CancellationToken)
  Stream.CopyToAsync(Stream, CancellationToken)
  Stream.Dispose()
  Stream.EndRead(IAsyncResult)
  Stream.EndWrite(IAsyncResult)
  Stream.FlushAsync()
  Stream.ReadAsync(byte[], int, int)
  Stream.ReadAtLeast(Span<byte>, int, bool)
  Stream.ReadAtLeastAsync(Memory<byte>, int, bool, CancellationToken)
  Stream.ReadByte()
  Stream.ReadExactly(byte[], int, int)
  Stream.ReadExactly(Span<byte>)
  Stream.ReadExactlyAsync(byte[], int, int, CancellationToken)
  Stream.ReadExactlyAsync(Memory<byte>, CancellationToken)
  Stream.Synchronized(Stream)
  Stream.WriteAsync(byte[], int, int)
  Stream.WriteByte(byte)
  MarshalByRefObject.GetLifetimeService()
  MarshalByRefObject.InitializeLifetimeService()
  object.Equals(object)
  object.Equals(object, object)
  object.GetHashCode()
  object.GetType()
  object.ReferenceEquals(object, object)
  object.ToString()

## Remarks

See https://www.postgresql.org/docs/current/static/sql-copy.html.

## Properties

### CanRead

When overridden in a derived class, gets a value indicating whether the current stream supports reading.

    public override bool CanRead { get; }

#### Property Value

bool

  true if the stream supports reading; otherwise, false.

### CanSeek

When overridden in a derived class, gets a value indicating whether the current stream supports seeking.

    public override bool CanSeek { get; }

#### Property Value

bool

  true if the stream supports seeking; otherwise, false.

### CanTimeout

Gets a value that determines whether the current stream can time out.

    public override bool CanTimeout { get; }

#### Property Value

bool

  A value that determines whether the current stream can time out.

### CanWrite

When overridden in a derived class, gets a value indicating whether the current stream supports writing.

    public override bool CanWrite { get; }

#### Property Value

bool

  true if the stream supports writing; otherwise, false.

### Length

When overridden in a derived class, gets the length in bytes of the stream.

    public override long Length { get; }

#### Property Value

long

  A long value representing the length of the stream in bytes.

#### Exceptions

NotSupportedException

  A class derived from `Stream` does not support seeking and the length is unknown.

ObjectDisposedException

  Methods were called after the stream was closed.

### Position

When overridden in a derived class, gets or sets the position within the current stream.

    public override long Position { get; set; }

#### Property Value

long

  The current position within the stream.

#### Exceptions

IOException

  An I/O error occurs.

NotSupportedException

  The stream does not support seeking.

ObjectDisposedException

  Methods were called after the stream was closed.

### ReadTimeout

Gets or sets a value, in milliseconds, that determines how long the stream will attempt to read before timing out.

    public override int ReadTimeout { get; set; }

#### Property Value

int

  A value, in milliseconds, that determines how long the stream will attempt to read before timing out.

#### Exceptions

InvalidOperationException

  The ReadTimeout method always throws an InvalidOperationException.

### WriteTimeout

Gets or sets a value, in milliseconds, that determines how long the stream will attempt to write before timing out.

    public override int WriteTimeout { get; set; }

#### Property Value

int

  A value, in milliseconds, that determines how long the stream will attempt to write before timing out.

#### Exceptions

InvalidOperationException

  The WriteTimeout method always throws an InvalidOperationException.

## Methods

### Cancel()

Cancels and terminates an ongoing operation. Any data already written will be discarded.

    public void Cancel()

### CancelAsync()

Cancels and terminates an ongoing operation. Any data already written will be discarded.

    public Task CancelAsync()

#### Returns

Task

### Dispose(bool)

Releases the unmanaged resources used by the Stream and optionally releases the managed resources.

    protected override void Dispose(bool disposing)

#### Parameters

`disposing` bool

  true to release both managed and unmanaged resources; false to release only unmanaged resources.

### DisposeAsync()

Asynchronously releases the unmanaged resources used by the Stream.

    public override ValueTask DisposeAsync()

#### Returns

ValueTask

  A task that represents the asynchronous dispose operation.

### Flush()

When overridden in a derived class, clears all buffers for this stream and causes any buffered data to be written to the underlying device.

    public override void Flush()

#### Exceptions

IOException

  An I/O error occurs.

### FlushAsync(CancellationToken)

Asynchronously clears all buffers for this stream, causes any buffered data to be written to the underlying device, and monitors cancellation requests.

    public override Task FlushAsync(CancellationToken cancellationToken)

#### Parameters

`cancellationToken` CancellationToken

  The token to monitor for cancellation requests. The default value is None.

#### Returns

Task

  A task that represents the asynchronous flush operation.

#### Exceptions

ObjectDisposedException

  The stream has been disposed.

OperationCanceledException

  The cancellation token was canceled. This exception is stored into the returned task.

### Read(byte[], int, int)

When overridden in a derived class, reads a sequence of bytes from the current stream and advances the position within the stream by the number of bytes read.

    public override int Read(byte[] buffer, int offset, int count)

#### Parameters

`buffer` byte[]

  An array of bytes. When this method returns, the buffer contains the specified byte array with the values between `offset` and (`offset` + `count` - 1) replaced by the bytes read from the current source.

`offset` int

  The zero-based byte offset in `buffer` at which to begin storing the data read from the current stream.

`count` int

  The maximum number of bytes to be read from the current stream.

#### Returns

int

  The total number of bytes read into the buffer. This can be less than the number of bytes requested if that many bytes are not currently available, or zero (0) if `count` is 0 or the end of the stream has been reached.

#### Exceptions

ArgumentException

  The sum of `offset` and `count` is larger than the buffer length.

ArgumentNullException

  `buffer` is null.

ArgumentOutOfRangeException

  `offset` or `count` is negative.

IOException

  An I/O error occurs.

NotSupportedException

  The stream does not support reading.

ObjectDisposedException

  Methods were called after the stream was closed.

### Read(Span<byte>)

When overridden in a derived class, reads a sequence of bytes from the current stream and advances the position within the stream by the number of bytes read.

    public override int Read(Span<byte> span)

#### Parameters

`span` Span<byte>

#### Returns

int

  The total number of bytes read into the buffer. This can be less than the size of the buffer if that many bytes are not currently available, or zero (0) if the buffer's length is zero or the end of the stream has been reached.

### ReadAsync(byte[], int, int, CancellationToken)

Asynchronously reads a sequence of bytes from the current stream, advances the position within the stream by the number of bytes read, and monitors cancellation requests.

    public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)

#### Parameters

`buffer` byte[]

  The buffer to write the data into.

`offset` int

  The byte offset in `buffer` at which to begin writing data from the stream.

`count` int

  The maximum number of bytes to read.

`cancellationToken` CancellationToken

  The token to monitor for cancellation requests. The default value is None.

#### Returns

Task<int>

  A task that represents the asynchronous read operation. The value of the `TResult` parameter contains the total number of bytes read into the buffer. The result value can be less than the number of bytes requested if the number of bytes currently available is less than the requested number, or it can be 0 (zero) if `count` is 0 or if the end of the stream has been reached.

#### Exceptions

ArgumentNullException

  `buffer` is null.

ArgumentOutOfRangeException

  `offset` or `count` is negative.

ArgumentException

  The sum of `offset` and `count` is larger than the buffer length.

NotSupportedException

  The stream does not support reading.

ObjectDisposedException

  The stream has been disposed.

InvalidOperationException

  The stream is currently in use by a previous read operation.

OperationCanceledException

  The cancellation token was canceled. This exception is stored into the returned task.

### ReadAsync(Memory<byte>, CancellationToken)

Asynchronously reads a sequence of bytes from the current stream, advances the position within the stream by the number of bytes read, and monitors cancellation requests.

    public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken)

#### Parameters

`buffer` Memory<byte>

  The region of memory to write the data into.

`cancellationToken` CancellationToken

  The token to monitor for cancellation requests. The default value is None.

#### Returns

ValueTask<int>

  A task that represents the asynchronous read operation. The value of its Result property contains the total number of bytes read into the buffer. The result value can be less than the length of the buffer if that many bytes are not currently available, or it can be 0 (zero) if the length of the buffer is 0 or if the end of the stream has been reached.

#### Exceptions

OperationCanceledException

  The cancellation token was canceled. This exception is stored into the returned task.

### Seek(long, SeekOrigin)

When overridden in a derived class, sets the position within the current stream.

    public override long Seek(long offset, SeekOrigin origin)

#### Parameters

`offset` long

  A byte offset relative to the `origin` parameter.

`origin` SeekOrigin

  A value of type SeekOrigin indicating the reference point used to obtain the new position.

#### Returns

long

  The new position within the current stream.

#### Exceptions

IOException

  An I/O error occurs.

NotSupportedException

  The stream does not support seeking, such as if the stream is constructed from a pipe or console output.

ObjectDisposedException

  Methods were called after the stream was closed.

### SetLength(long)

When overridden in a derived class, sets the length of the current stream.

    public override void SetLength(long value)

#### Parameters

`value` long

  The desired length of the current stream in bytes.

#### Exceptions

IOException

  An I/O error occurs.

NotSupportedException

  The stream does not support both writing and seeking, such as if the stream is constructed from a pipe or console output.

ObjectDisposedException

  Methods were called after the stream was closed.

### Write(byte[], int, int)

When overridden in a derived class, writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written.

    public override void Write(byte[] buffer, int offset, int count)

#### Parameters

`buffer` byte[]

  An array of bytes. This method copies `count` bytes from `buffer` to the current stream.

`offset` int

  The zero-based byte offset in `buffer` at which to begin copying bytes to the current stream.

`count` int

  The number of bytes to be written to the current stream.

#### Exceptions

ArgumentException

  The sum of `offset` and `count` is greater than the buffer length.

ArgumentNullException

  `buffer` is null.

ArgumentOutOfRangeException

  `offset` or `count` is negative.

IOException

  An I/O error occurred, such as the specified file cannot be found.

NotSupportedException

  The stream does not support writing.

ObjectDisposedException

  Write(byte[], int, int) was called after the stream was closed.

### Write(ReadOnlySpan<byte>)

When overridden in a derived class, writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written.

    public override void Write(ReadOnlySpan<byte> buffer)

#### Parameters

`buffer` ReadOnlySpan<byte>

  A region of memory. This method copies the contents of this region to the current stream.

### WriteAsync(byte[], int, int, CancellationToken)

Asynchronously writes a sequence of bytes to the current stream, advances the current position within this stream by the number of bytes written, and monitors cancellation requests.

    public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)

#### Parameters

`buffer` byte[]

  The buffer to write data from.

`offset` int

  The zero-based byte offset in `buffer` from which to begin copying bytes to the stream.

`count` int

  The maximum number of bytes to write.

`cancellationToken` CancellationToken

  The token to monitor for cancellation requests. The default value is None.

#### Returns

Task

  A task that represents the asynchronous write operation.

#### Exceptions

ArgumentNullException

  `buffer` is null.

ArgumentOutOfRangeException

  `offset` or `count` is negative.

ArgumentException

  The sum of `offset` and `count` is larger than the buffer length.

NotSupportedException

  The stream does not support writing.

ObjectDisposedException

  The stream has been disposed.

InvalidOperationException

  The stream is currently in use by a previous write operation.

OperationCanceledException

  The cancellation token was canceled. This exception is stored into the returned task.

### WriteAsync(ReadOnlyMemory<byte>, CancellationToken)

Asynchronously writes a sequence of bytes to the current stream, advances the current position within this stream by the number of bytes written, and monitors cancellation requests.

    public override ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = default)

#### Parameters

`buffer` ReadOnlyMemory<byte>

  The region of memory to write data from.

`cancellationToken` CancellationToken

  The token to monitor for cancellation requests. The default value is None.

#### Returns

ValueTask

  A task that represents the asynchronous write operation.

#### Exceptions

OperationCanceledException

  The cancellation token was canceled. This exception is stored into the returned task.