IDedupReadFileCallback::PreviewContainerRead method

Provides the application with a preview of the sequence of reads that are pending for a given container file extent.

Syntax


HRESULT PreviewContainerRead(
  [in]                         BSTR            FileFullPath,
  [in]                         ULONG           NumberOfReads,
  [in, size_is(NumberOfReads)] DDP_FILE_EXTENT *ReadOffsets
);

Parameters

FileFullPath [in]

The full path from the root directory of the volume to the container file.

NumberOfReads [in]

Number of DDP_FILE_EXTENT structures in the array that the ReadOffsets parameter points to.

ReadOffsets [in]

Pointer to an array of DDP_FILE_EXTENT structures.

Return value

This method can return standard HRESULT values, such as S_OK. It can also return converted system error codes using the HRESULT_FROM_WIN32 macro. Possible return values include the following.

S_OK

0x00000000L

The method completed successfully.

DDP_E_PATH_NOT_FOUND

0x80565304L

The specified container path was not found in the backup store.

Remarks

PreviewContainerRead is called for each container file extent reported by IDedupReadFileCallback::OrderContainersRestore. The application may use this preview as a per-container extent read plan to increase the efficiency of the pending reads. For example, the application may choose to perform read-ahead to improve throughput or to cache read buffers to improve overall performance across parallel file restore operations.

Requirements

Minimum supported client

None supported

Minimum supported server

Windows Server 2012

Header

DdpBackup.h

See also

IDedupReadFileCallback
DDP_FILE_EXTENT

 

 

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