NativeIO (druid-processing 28.0.0 API)

java.lang.Object
- org.apache.druid.java.util.common.io.NativeIO

```
public class NativeIO
extends Object
```
Native I/O operations in order to minimize cache impact.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static void`	`chunkedCopy(InputStream src, File dest)`	Copy from an input stream to a file minimizing cache impact on the destination..
`static int`	`getfd(FileDescriptor descriptor)`	Get system file descriptor (int) from FileDescriptor object.
`static void`	`trySkipCache(int fd, long offset, long len)`	Remove pages from the file system page cache when they wont be accessed again

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - getfd
```
public static int getfd(FileDescriptor descriptor)
```
    Get system file descriptor (int) from FileDescriptor object.
    
    Parameters:
    
    descriptor - - FileDescriptor object to get fd from
    
    Returns:
    
    file descriptor, -1 or error
  - trySkipCache
```
public static void trySkipCache(int fd,
                                long offset,
                                long len)
```
    Remove pages from the file system page cache when they wont be accessed again
    
    Parameters:
    
    fd - The file descriptor of the source file.
    
    offset - The offset within the file.
    
    len - The length to be flushed.
  - chunkedCopy
```
public static void chunkedCopy(InputStream src,
                               File dest)
                        throws IOException
```
    Copy from an input stream to a file minimizing cache impact on the destination.. This happens chunk by chunk so only at most chunk size will be present in the OS page cache. Posix (Linux, BSD) only. The implementation in this method is based on a post by Linus Torvalds here: http://lkml.iu.edu/hypermail/linux/kernel/1005.2/01845.html
    
    Parameters:
    
    src - Source InputStream where to copy from
    
    dest - Destination file to copy to
    
    Throws:
    
    IOException