org.apache.lucene.index

Class CheckIndex

java.lang.Object

org.apache.lucene.index.CheckIndex

public class CheckIndex
extends Object

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

Please make a complete backup of your index before using this to fix your index!

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CheckIndex.Status Returned from checkIndex() detailing the health and status of the index.

Constructor Summary

Constructors

Constructor and Description
CheckIndex(Directory dir) Create a new CheckIndex on the directory.

Method Summary

Methods

Modifier and Type	Method and Description
CheckIndex.Status	checkIndex() Returns a CheckIndex.Status instance detailing the state of the index.
CheckIndex.Status	checkIndex(List<String> onlySegments) 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.

Methods inherited from class java.lang.Object

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

Constructor Detail

CheckIndex

public CheckIndex(Directory dir)

Create a new CheckIndex on the directory.

Method Detail

setInfoStream

public void setInfoStream(PrintStream out)

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

checkIndex

public CheckIndex.Status checkIndex()
                             throws IOException

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

checkIndex

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

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

fixIndex

public void fixIndex(CheckIndex.Status result)
              throws IOException

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

main

public static void main(String[] args)
                 throws IOException,
                        InterruptedException

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