Class NpgsqlLargeObjectManager
Large object manager. This class can be used to store very large files in a PostgreSQL database.
Inheritance
Namespace: Npgsql
Assembly: Npgsql.dll
Syntax
public class NpgsqlLargeObjectManagerConstructors
| Improve this Doc View SourceNpgsqlLargeObjectManager(NpgsqlConnection)
Creates an NpgsqlLargeObjectManager for this connection. The connection must be opened to perform remote operations.
Declaration
public NpgsqlLargeObjectManager(NpgsqlConnection connection)Parameters
| Type | Name | Description |
|---|---|---|
| NpgsqlConnection | connection |
Properties
| Improve this Doc View SourceHas64BitSupport
Since PostgreSQL 9.3, large objects larger than 2GB can be handled, up to 4TB. This property returns true whether the PostgreSQL version is >= 9.3.
Declaration
public bool Has64BitSupport { get; }Property Value
| Type | Description |
|---|---|
| bool |
MaxTransferBlockSize
The largest chunk size (in bytes) read and write operations will read/write each roundtrip to the network. Default 4 MB.
Declaration
public int MaxTransferBlockSize { get; set; }Property Value
| Type | Description |
|---|---|
| int |
Methods
| Improve this Doc View SourceCreate(uint)
Create an empty large object in the database. If an oid is specified but is already in use, an PostgresException will be thrown.
Declaration
public uint Create(uint preferredOid = null)Parameters
| Type | Name | Description |
|---|---|---|
| uint | preferredOid | A preferred oid, or specify 0 if one should be automatically assigned |
Returns
| Type | Description |
|---|---|
| uint | The oid for the large object created |
Exceptions
| Type | Condition |
|---|---|
| PostgresException | If an oid is already in use |
CreateAsync(uint, CancellationToken)
Create an empty large object in the database. If an oid is specified but is already in use, an PostgresException will be thrown.
Declaration
public Task<uint> CreateAsync(uint preferredOid, CancellationToken cancellationToken = null)Parameters
| Type | Name | Description |
|---|---|---|
| uint | preferredOid | A preferred oid, or specify 0 if one should be automatically assigned |
| CancellationToken | cancellationToken | An optional token to cancel the asynchronous operation. The default value is |
Returns
| Type | Description |
|---|---|
| Task<><uint> | The oid for the large object created |
Exceptions
| Type | Condition |
|---|---|
| PostgresException | If an oid is already in use |
ExportRemote(uint, string)
Exports a large object stored in the database to a file on the backend. This requires superuser permissions.
Declaration
public void ExportRemote(uint oid, string path)Parameters
| Type | Name | Description |
|---|---|---|
| uint | oid | Oid of the object to export |
| string | path | Path to write the file on the backend |
ExportRemoteAsync(uint, string, CancellationToken)
Exports a large object stored in the database to a file on the backend. This requires superuser permissions.
Declaration
public Task ExportRemoteAsync(uint oid, string path, CancellationToken cancellationToken = null)Parameters
| Type | Name | Description |
|---|---|---|
| uint | oid | Oid of the object to export |
| string | path | Path to write the file on the backend |
| CancellationToken | cancellationToken | An optional token to cancel the asynchronous operation. The default value is |
Returns
| Type | Description |
|---|---|
| Task |
ImportRemote(string, uint)
Imports a large object to be stored as a large object in the database from a file stored on the backend. This requires superuser permissions.
Declaration
public void ImportRemote(string path, uint oid = null)Parameters
| Type | Name | Description |
|---|---|---|
| string | path | Path to read the file on the backend |
| uint | oid | A preferred oid, or specify 0 if one should be automatically assigned |
ImportRemoteAsync(string, uint, CancellationToken)
Imports a large object to be stored as a large object in the database from a file stored on the backend. This requires superuser permissions.
Declaration
public Task ImportRemoteAsync(string path, uint oid, CancellationToken cancellationToken = null)Parameters
| Type | Name | Description |
|---|---|---|
| string | path | Path to read the file on the backend |
| uint | oid | A preferred oid, or specify 0 if one should be automatically assigned |
| CancellationToken | cancellationToken | An optional token to cancel the asynchronous operation. The default value is |
Returns
| Type | Description |
|---|---|
| Task |
OpenRead(uint)
Opens a large object on the backend, returning a stream controlling this remote object. A transaction snapshot is taken by the backend when the object is opened with only read permissions. When reading from this object, the contents reflects the time when the snapshot was taken. Note that this method, as well as operations on the stream must be wrapped inside a transaction.
Declaration
public NpgsqlLargeObjectStream OpenRead(uint oid)Parameters
| Type | Name | Description |
|---|---|---|
| uint | oid | Oid of the object |
Returns
| Type | Description |
|---|---|
| NpgsqlLargeObjectStream | An NpgsqlLargeObjectStream |
OpenReadAsync(uint, CancellationToken)
Opens a large object on the backend, returning a stream controlling this remote object. A transaction snapshot is taken by the backend when the object is opened with only read permissions. When reading from this object, the contents reflects the time when the snapshot was taken. Note that this method, as well as operations on the stream must be wrapped inside a transaction.
Declaration
public Task<NpgsqlLargeObjectStream> OpenReadAsync(uint oid, CancellationToken cancellationToken = null)Parameters
| Type | Name | Description |
|---|---|---|
| uint | oid | Oid of the object |
| CancellationToken | cancellationToken | An optional token to cancel the asynchronous operation. The default value is |
Returns
| Type | Description |
|---|---|
| Task<><NpgsqlLargeObjectStream> | An NpgsqlLargeObjectStream |
OpenReadWrite(uint)
Opens a large object on the backend, returning a stream controlling this remote object. Note that this method, as well as operations on the stream must be wrapped inside a transaction.
Declaration
public NpgsqlLargeObjectStream OpenReadWrite(uint oid)Parameters
| Type | Name | Description |
|---|---|---|
| uint | oid | Oid of the object |
Returns
| Type | Description |
|---|---|
| NpgsqlLargeObjectStream | An NpgsqlLargeObjectStream |
OpenReadWriteAsync(uint, CancellationToken)
Opens a large object on the backend, returning a stream controlling this remote object. Note that this method, as well as operations on the stream must be wrapped inside a transaction.
Declaration
public Task<NpgsqlLargeObjectStream> OpenReadWriteAsync(uint oid, CancellationToken cancellationToken = null)Parameters
| Type | Name | Description |
|---|---|---|
| uint | oid | Oid of the object |
| CancellationToken | cancellationToken | An optional token to cancel the asynchronous operation. The default value is |
Returns
| Type | Description |
|---|---|
| Task<><NpgsqlLargeObjectStream> | An NpgsqlLargeObjectStream |
Unlink(uint)
Deletes a large object on the backend.
Declaration
public void Unlink(uint oid)Parameters
| Type | Name | Description |
|---|---|---|
| uint | oid | Oid of the object to delete |
UnlinkAsync(uint, CancellationToken)
Deletes a large object on the backend.
Declaration
public Task UnlinkAsync(uint oid, CancellationToken cancellationToken = null)Parameters
| Type | Name | Description |
|---|---|---|
| uint | oid | Oid of the object to delete |
| CancellationToken | cancellationToken | An optional token to cancel the asynchronous operation. The default value is |
Returns
| Type | Description |
|---|---|
| Task |