org.apache.lucene.store
Class DirectIOLinuxDirectory

java.lang.Object
  org.apache.lucene.store.Directory
      org.apache.lucene.store.FSDirectory
          org.apache.lucene.store.DirectIOLinuxDirectory

All Implemented Interfaces:

Closeable

public class DirectIOLinuxDirectory
extends FSDirectory

An Directory implementation that uses the Linux-specific O_DIRECT flag to bypass all OS level caching. To use this you must compile NativePosixUtil.cpp (exposes Linux-specific APIs through JNI) for your platform.

WARNING: this code is very new and quite easily could contain horrible bugs. For example, here's one known issue: if you use seek in IndexOutput, and then write more than one buffer's worth of bytes, then the file will be wrong. Lucene does not do this (only writes small number of bytes after seek).

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.store.FSDirectory

FSDirectory.FSIndexOutput

Field Summary

Fields inherited from class org.apache.lucene.store.FSDirectory

DEFAULT_READ_CHUNK_SIZE, directory, staleFiles

Fields inherited from class org.apache.lucene.store.Directory

isOpen, lockFactory

Constructor Summary

DirectIOLinuxDirectory(File path, LockFactory lockFactory, int forcedBufferSize)
Create a new NIOFSDirectory for the named location.

Method Summary

IndexOutput	createOutput(String name) Creates an IndexOutput for the file with the given name.
IndexInput	openInput(String name, int bufferSize) Returns a stream reading an existing file, with the specified read buffer size.

Methods inherited from class org.apache.lucene.store.FSDirectory

close, deleteFile, ensureCanWrite, fileExists, fileLength, fileModified, fileModified, fsync, getDirectory, getFile, getLockID, getReadChunkSize, listAll, listAll, onIndexOutputClosed, open, open, openInput, setLockFactory, setReadChunkSize, sync, sync, toString, touchFile

Methods inherited from class org.apache.lucene.store.Directory

clearLock, copy, copy, ensureOpen, getLockFactory, makeLock

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DirectIOLinuxDirectory

public DirectIOLinuxDirectory(File path,
                              LockFactory lockFactory,
                              int forcedBufferSize)
                       throws IOException

Create a new NIOFSDirectory for the named location.

Parameters:

path - the path of the directory

lockFactory - the lock factory to use, or null for the default (NativeFSLockFactory);

forcedBufferSize - if this is 0, just use Lucene's default buffer size; else, force this buffer size. For best performance, force the buffer size to something fairly large (eg 1 MB), but note that this will eat up the JRE's direct buffer storage space

Throws:

IOException

Method Detail

openInput

public IndexInput openInput(String name,
                            int bufferSize)
                     throws IOException

Description copied from class: Directory

Returns a stream reading an existing file, with the specified read buffer size. The particular Directory implementation may ignore the buffer size. Currently the only Directory implementations that respect this parameter are FSDirectory and CompoundFileReader.

Overrides:

openInput in class Directory

Throws:

IOException

createOutput

public IndexOutput createOutput(String name)
                         throws IOException

Description copied from class: FSDirectory

Creates an IndexOutput for the file with the given name.

Overrides:

createOutput in class FSDirectory

Throws:

IOException