Class NativeFSLockFactory
Implements LockFactory
using native OS file
locks. Note that because this LockFactory relies on
java.nio.* APIs for locking, any problems with those APIs
will cause locking to fail. Specifically, on certain NFS
environments the java.nio.* locks will fail (the lock can
incorrectly be double acquired) whereas SimpleFSLockFactory
worked perfectly in those same
environments. For NFS based access to an index, it's
recommended that you try SimpleFSLockFactory
first and work around the one limitation that a lock file
could be left when the JVM exits abnormally.
The primary benefit of NativeFSLockFactory
is
that lock files will be properly removed (by the OS) if
the JVM has an abnormal exit.
Note that, unlike SimpleFSLockFactory
, the existence of
leftover lock files in the filesystem on exiting the JVM
is fine because the OS will free the locks held against
these files even though the files still remain.
If you suspect that this or any other LockFactory is
not working properly in your environment, you can easily
test it by using VerifyingLockFactory
, LockVerifyServer
and LockStressTest
.
- See Also:
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Field Summary
Fields inherited from class org.apache.lucene.store.FSLockFactory
lockDir
Fields inherited from class org.apache.lucene.store.LockFactory
lockPrefix
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Constructor Summary
ConstructorsConstructorDescriptionCreate a NativeFSLockFactory instance, with null (unset) lock directory.NativeFSLockFactory
(File lockDir) Create a NativeFSLockFactory instance, storing lock files into the specified lockDir:NativeFSLockFactory
(String lockDirName) Create a NativeFSLockFactory instance, storing lock files into the specified lockDirName: -
Method Summary
Methods inherited from class org.apache.lucene.store.FSLockFactory
getLockDir, setLockDir, toString
Methods inherited from class org.apache.lucene.store.LockFactory
getLockPrefix, setLockPrefix
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Constructor Details
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NativeFSLockFactory
public NativeFSLockFactory()Create a NativeFSLockFactory instance, with null (unset) lock directory. When you pass this factory to aFSDirectory
subclass, the lock directory is automatically set to the directory itself. Be sure to create one instance for each directory your create! -
NativeFSLockFactory
Create a NativeFSLockFactory instance, storing lock files into the specified lockDirName:- Parameters:
lockDirName
- where lock files are created.
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NativeFSLockFactory
Create a NativeFSLockFactory instance, storing lock files into the specified lockDir:- Parameters:
lockDir
- where lock files are created.
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Method Details
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makeLock
Description copied from class:LockFactory
Return a new Lock instance identified by lockName.- Specified by:
makeLock
in classLockFactory
- Parameters:
lockName
- name of the lock to be created.
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clearLock
Description copied from class:LockFactory
Attempt to clear (forcefully unlock and remove) the specified lock. Only call this at a time when you are certain this lock is no longer in use.- Specified by:
clearLock
in classLockFactory
- Parameters:
lockName
- name of the lock to be cleared.- Throws:
IOException
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