Class IndexWriterConfig

Holds all the configuration that is used to create an IndexWriter. Once IndexWriter has been created with this object, changes to this object will not affect the IndexWriter instance. For that, use LiveIndexWriterConfig that is returned from Config.

LUCENENET NOTE: Unlike Lucene, we use property setters instead of setter methods. In C#, this allows you to initialize the IndexWriterConfig using the language features of C#, for example:

    IndexWriterConfig conf = new IndexWriterConfig(analyzer)
    {
        Codec = Lucene46Codec(),
        OpenMode = OpenMode.CREATE
    };

However, if you prefer to match the syntax of Lucene using chained setter methods, there are extension methods in the Lucene.Net.Support namespace. Example usage:

    using Lucene.Net.Support;

    ..

    IndexWriterConfig conf = new IndexWriterConfig(analyzer)
        .SetCodec(new Lucene46Codec())
        .SetOpenMode(OpenMode.CREATE);

@since 3.1

Inheritance
System.Object
LiveIndexWriterConfig
IndexWriterConfig
Inherited Members
Namespace: Lucene.Net.Index
Assembly: Lucene.Net.dll
Syntax
public sealed class IndexWriterConfig : LiveIndexWriterConfig

Constructors

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IndexWriterConfig(LuceneVersion, Analyzer)

Creates a new config that with defaults that match the specified LuceneVersion as well as the default Analyzer. If matchVersion is >= LUCENE_32, TieredMergePolicy is used for merging; else LogByteSizeMergePolicy. Note that TieredMergePolicy is free to select non-contiguous merges, which means docIDs may not remain monotonic over time. If this is a problem you should switch to LogByteSizeMergePolicy or LogDocMergePolicy.

Declaration
public IndexWriterConfig(LuceneVersion matchVersion, Analyzer analyzer)
Parameters
Type Name Description
LuceneVersion matchVersion
Analyzer analyzer

Fields

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DEFAULT_CHECK_INTEGRITY_AT_MERGE

Default value for calling CheckIntegrity() before merging segments (set to false). You can set this to true for additional safety.

Declaration
public static readonly bool DEFAULT_CHECK_INTEGRITY_AT_MERGE
Field Value
Type Description
System.Boolean
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DEFAULT_MAX_BUFFERED_DELETE_TERMS

Disabled by default (because IndexWriter flushes by RAM usage by default).

Declaration
public static readonly int DEFAULT_MAX_BUFFERED_DELETE_TERMS
Field Value
Type Description
System.Int32
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DEFAULT_MAX_BUFFERED_DOCS

Disabled by default (because IndexWriter flushes by RAM usage by default).

Declaration
public static readonly int DEFAULT_MAX_BUFFERED_DOCS
Field Value
Type Description
System.Int32
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DEFAULT_MAX_THREAD_STATES

The maximum number of simultaneous threads that may be indexing documents at once in IndexWriter; if more than this many threads arrive they will wait for others to finish. Default value is 8.

Declaration
public static readonly int DEFAULT_MAX_THREAD_STATES
Field Value
Type Description
System.Int32
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DEFAULT_RAM_BUFFER_SIZE_MB

Default value is 16 MB (which means flush when buffered docs consume approximately 16 MB RAM).

Declaration
public static readonly double DEFAULT_RAM_BUFFER_SIZE_MB
Field Value
Type Description
System.Double
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DEFAULT_RAM_PER_THREAD_HARD_LIMIT_MB

Default value is 1945. Change using RAMPerThreadHardLimitMB setter.

Declaration
public static readonly int DEFAULT_RAM_PER_THREAD_HARD_LIMIT_MB
Field Value
Type Description
System.Int32
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DEFAULT_READER_POOLING

Default setting for UseReaderPooling.

Declaration
public static readonly bool DEFAULT_READER_POOLING
Field Value
Type Description
System.Boolean
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DEFAULT_READER_TERMS_INDEX_DIVISOR

Default value is 1. Change using ReaderTermsIndexDivisor setter.

Declaration
public static readonly int DEFAULT_READER_TERMS_INDEX_DIVISOR
Field Value
Type Description
System.Int32
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DEFAULT_TERM_INDEX_INTERVAL

Default value is 32. Change using TermIndexInterval setter.

Declaration
public static readonly int DEFAULT_TERM_INDEX_INTERVAL
Field Value
Type Description
System.Int32
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DEFAULT_USE_COMPOUND_FILE_SYSTEM

Default value for compound file system for newly written segments (set to true). For batch indexing with very large ram buffers use false

Declaration
public static readonly bool DEFAULT_USE_COMPOUND_FILE_SYSTEM
Field Value
Type Description
System.Boolean
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DISABLE_AUTO_FLUSH

Denotes a flush trigger is disabled.

Declaration
public static readonly int DISABLE_AUTO_FLUSH
Field Value
Type Description
System.Int32
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WRITE_LOCK_TIMEOUT

Default value for the write lock timeout (1,000 ms).

Declaration
public static long WRITE_LOCK_TIMEOUT
Field Value
Type Description
System.Int64

Properties

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Codec

Gets or sets the Codec.

Only takes effect when IndexWriter is first created.

Declaration
public Codec Codec { get; set; }
Property Value
Type Description
Codec
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DefaultWriteLockTimeout

Gets or sets the default (for any instance) maximum time to wait for a write lock (in milliseconds).

Declaration
public static long DefaultWriteLockTimeout { get; set; }
Property Value
Type Description
System.Int64
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IndexCommit

Expert: allows to open a certain commit point. The default is null which opens the latest commit point.

Only takes effect when IndexWriter is first created.

Declaration
public IndexCommit IndexCommit { get; set; }
Property Value
Type Description
IndexCommit
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IndexDeletionPolicy

Expert: allows an optional IndexDeletionPolicy implementation to be specified. You can use this to control when prior commits are deleted from the index. The default policy is KeepOnlyLastCommitDeletionPolicy which removes all prior commits as soon as a new commit is done (this matches behavior before 2.2). Creating your own policy can allow you to explicitly keep previous "point in time" commits alive in the index for some time, to allow readers to refresh to the new commit without having the old commit deleted out from under them. This is necessary on filesystems like NFS that do not support "delete on last close" semantics, which Lucene's "point in time" search normally relies on.

NOTE: the deletion policy cannot be null.

Only takes effect when IndexWriter is first created.

Declaration
public IndexDeletionPolicy IndexDeletionPolicy { get; set; }
Property Value
Type Description
IndexDeletionPolicy
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MaxThreadStates

Gets or sets the max number of simultaneous threads that may be indexing documents at once in IndexWriter. Values < 1 are invalid and if passed maxThreadStates will be set to DEFAULT_MAX_THREAD_STATES.

Only takes effect when IndexWriter is first created.

Declaration
public int MaxThreadStates { get; set; }
Property Value
Type Description
System.Int32
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MergePolicy

Expert: MergePolicy is invoked whenever there are changes to the segments in the index. Its role is to select which merges to do, if any, and return a MergePolicy.MergeSpecification describing the merges. It also selects merges to do for ForceMerge(Int32).

Only takes effect when IndexWriter is first created.

Declaration
public MergePolicy MergePolicy { get; set; }
Property Value
Type Description
MergePolicy
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MergeScheduler

Expert: Gets or sets the merge scheduler used by this writer. The default is ConcurrentMergeScheduler.

NOTE: the merge scheduler cannot be null.

Only takes effect when IndexWriter is first created.

Declaration
public IMergeScheduler MergeScheduler { get; set; }
Property Value
Type Description
IMergeScheduler
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OpenMode

Specifies OpenMode of the index.

Only takes effect when IndexWriter is first created.

Declaration
public OpenMode OpenMode { get; set; }
Property Value
Type Description
OpenMode
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RAMPerThreadHardLimitMB

Expert: Gets or sets the maximum memory consumption per thread triggering a forced flush if exceeded. A Lucene.Net.Index.DocumentsWriterPerThread is forcefully flushed once it exceeds this limit even if the RAMBufferSizeMB has not been exceeded. This is a safety limit to prevent a Lucene.Net.Index.DocumentsWriterPerThread from address space exhaustion due to its internal 32 bit signed integer based memory addressing. The given value must be less that 2GB (2048MB).

Declaration
public int RAMPerThreadHardLimitMB { get; set; }
Property Value
Type Description
System.Int32
See Also
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Similarity

Expert: set the Similarity implementation used by this IndexWriter.

NOTE: the similarity cannot be null.

Only takes effect when IndexWriter is first created.

Declaration
public Similarity Similarity { get; set; }
Property Value
Type Description
Similarity
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UseReaderPooling

By default, IndexWriter does not pool the SegmentReaders it must open for deletions and merging, unless a near-real-time reader has been obtained by calling Open(IndexWriter, Boolean). this setting lets you enable pooling without getting a near-real-time reader. NOTE: if you set this to false, IndexWriter will still pool readers once Open(IndexWriter, Boolean) is called.

Only takes effect when IndexWriter is first created.

Declaration
public bool UseReaderPooling { get; set; }
Property Value
Type Description
System.Boolean
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WriteLockTimeout

Gets or sets the maximum time to wait for a write lock (in milliseconds) for this instance. You can change the default value for all instances by calling the DefaultWriteLockTimeout setter.

Only takes effect when IndexWriter is first created.

Declaration
public long WriteLockTimeout { get; set; }
Property Value
Type Description
System.Int64

Methods

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Clone()

Declaration
public object Clone()
Returns
Type Description
System.Object
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SetInfoStream(InfoStream)

Information about merges, deletes and a message when maxFieldLength is reached will be printed to this. Must not be null, but NO_OUTPUT may be used to supress output.

Declaration
public IndexWriterConfig SetInfoStream(InfoStream infoStream)
Parameters
Type Name Description
InfoStream infoStream
Returns
Type Description
IndexWriterConfig
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SetInfoStream(TextWriter)

Convenience method that uses TextWriterInfoStream to write to the passed in . Must not be null.

Declaration
public IndexWriterConfig SetInfoStream(TextWriter printStream)
Parameters
Type Name Description
TextWriter printStream
Returns
Type Description
IndexWriterConfig
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ToString()

Declaration
public override string ToString()
Returns
Type Description
System.String
Overrides

Extension Methods

See Also