public class

CheckIndex

extends Object
java.lang.Object
   ↳ org.apache.lucene.index.CheckIndex

Class Overview

Basic tool and API to check the health of an index and write a new segments file that removes reference to problematic segments.

As this tool checks every byte in the index, on a large index it can take quite a long time to run.

WARNING: this tool and API is new and experimental and is subject to suddenly change in the next release. Please make a complete backup of your index before using this to fix your index!

Summary

Nested Classes
class CheckIndex.Status Returned from checkIndex() detailing the health and status of the index. 
Public Constructors
CheckIndex(Directory dir)
Create a new CheckIndex on the directory.
Public Methods
CheckIndex.Status checkIndex(List<String> onlySegments)
Returns a CheckIndex.Status instance detailing the state of the index.
CheckIndex.Status checkIndex()
Returns a CheckIndex.Status instance detailing the state of the index.
void fixIndex(CheckIndex.Status result)
Repairs the index using previously returned result from checkIndex().
static void main(String[] args)
Command-line interface to check and fix an index.
void setInfoStream(PrintStream out)
Set infoStream where messages should go.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public CheckIndex (Directory dir)

Create a new CheckIndex on the directory.

Public Methods

public CheckIndex.Status checkIndex (List<String> onlySegments)

Returns a CheckIndex.Status instance detailing the state of the index.

Parameters
onlySegments list of specific segment names to check

As this method checks every byte in the specified segments, on a large index it can take quite a long time to run.

WARNING: make sure you only call this when the index is not opened by any writer.

Throws
IOException

public CheckIndex.Status checkIndex ()

Returns a CheckIndex.Status instance detailing the state of the index.

As this method checks every byte in the index, on a large index it can take quite a long time to run.

WARNING: make sure you only call this when the index is not opened by any writer.

Throws
IOException

public void fixIndex (CheckIndex.Status result)

Repairs the index using previously returned result from checkIndex(). Note that this does not remove any of the unreferenced files after it's done; you must separately open an IndexWriter, which deletes unreferenced files when it's created.

WARNING: this writes a new segments file into the index, effectively removing all documents in broken segments from the index. BE CAREFUL.

WARNING: Make sure you only call this when the index is not opened by any writer.

Throws
IOException

public static void main (String[] args)

Command-line interface to check and fix an index.

Run it like this: 

    java -ea:org.apache.lucene... org.apache.lucene.index.CheckIndex pathToIndex [-fix] [-segment X] [-segment Y]
  • -fix: actually write a new segments_N file, removing any problematic segments
  • -segment X: only check the specified segment(s). This can be specified multiple times, to check more than one segment, eg -segment _2 -segment _a. You can't use this with the -fix option.

WARNING: -fix should only be used on an emergency basis as it will cause documents (perhaps many) to be permanently removed from the index. Always make a backup copy of your index before running this! Do not run this tool on an index that is actively being written to. You have been warned!

Run without -fix, this tool will open the index, report version information and report any exceptions it hits and what action it would take if -fix were specified. With -fix, this tool will remove any segments that have issues and write a new segments_N file. This means all documents contained in the affected segments will be removed.

This tool exits with exit code 1 if the index cannot be opened or has any corruption, else 0.

Throws
IOException
InterruptedException

public void setInfoStream (PrintStream out)

Set infoStream where messages should go. If null, no messages are printed