Class SearcherManager

Utility class to safely share IndexSearcher instances across multiple threads, while periodically reopening. This class ensures each searcher is disposed only once all threads have finished using it.

Use Acquire() to obtain the current searcher, and Release(G) to release it, like this:

IndexSearcher s = manager.Acquire();
try 
{
    // Do searching, doc retrieval, etc. with s
} 
finally 
{
    manager.Release(s);
    // Do not use s after this!
    s = null;
}

In addition you should periodically call MaybeRefresh(). While it's possible to call this just before running each query, this is discouraged since it penalizes the unlucky queries that do the reopen. It's better to use a separate background thread, that periodically calls MaybeRefresh(). Finally, be sure to call Dispose() once you are done.

Note

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

Inheritance
System.Object
ReferenceManager<IndexSearcher>
SearcherManager
Implements
System.IDisposable
Inherited Members
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
System.Object.ToString()
Namespace: Lucene.Net.Search
Assembly: Lucene.Net.dll
Syntax
public sealed class SearcherManager : ReferenceManager<IndexSearcher>, IDisposable

Constructors

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SearcherManager(IndexWriter, Boolean, SearcherFactory)

Creates and returns a new SearcherManager from the given IndexWriter.

Declaration
public SearcherManager(IndexWriter writer, bool applyAllDeletes, SearcherFactory searcherFactory)
Parameters
Type Name Description
IndexWriter writer

The IndexWriter to open the IndexReader from.

System.Boolean applyAllDeletes

If true, all buffered deletes will be applied (made visible) in the IndexSearcher / DirectoryReader. If false, the deletes may or may not be applied, but remain buffered (in IndexWriter) so that they will be applied in the future. Applying deletes can be costly, so if your app can tolerate deleted documents being returned you might gain some performance by passing false. See OpenIfChanged(DirectoryReader, IndexWriter, Boolean).

SearcherFactory searcherFactory

An optional SearcherFactory. Pass null if you don't require the searcher to be warmed before going live or other custom behavior.
Exceptions
Type Condition
System.IO.IOException

if there is a low-level I/O error

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SearcherManager(Directory, SearcherFactory)

Creates and returns a new SearcherManager from the given Directory.

Declaration
public SearcherManager(Directory dir, SearcherFactory searcherFactory)
Parameters
Type Name Description
Directory dir

The directory to open the DirectoryReader on.

SearcherFactory searcherFactory

An optional SearcherFactory. Pass null if you don't require the searcher to be warmed before going live or other custom behavior.
Exceptions
Type Condition
System.IO.IOException

If there is a low-level I/O error

Methods

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DecRef(IndexSearcher)

Declaration
protected override void DecRef(IndexSearcher reference)
Parameters
Type Name Description
IndexSearcher reference
Overrides
Lucene.Net.Search.ReferenceManager<Lucene.Net.Search.IndexSearcher>.DecRef(Lucene.Net.Search.IndexSearcher)
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GetRefCount(IndexSearcher)

Declaration
protected override int GetRefCount(IndexSearcher reference)
Parameters
Type Name Description
IndexSearcher reference
Returns
Type Description
System.Int32
Overrides
Lucene.Net.Search.ReferenceManager<Lucene.Net.Search.IndexSearcher>.GetRefCount(Lucene.Net.Search.IndexSearcher)
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GetSearcher(SearcherFactory, IndexReader)

Expert: creates a searcher from the provided IndexReader using the provided SearcherFactory. NOTE: this decRefs incoming reader on throwing an exception.

Declaration
public static IndexSearcher GetSearcher(SearcherFactory searcherFactory, IndexReader reader)
Parameters
Type Name Description
SearcherFactory searcherFactory
IndexReader reader
Returns
Type Description
IndexSearcher
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IsSearcherCurrent()

Returns true if no changes have occured since this searcher ie. reader was opened, otherwise false.

Declaration
public bool IsSearcherCurrent()
Returns
Type Description
System.Boolean
See Also
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RefreshIfNeeded(IndexSearcher)

Declaration
protected override IndexSearcher RefreshIfNeeded(IndexSearcher referenceToRefresh)
Parameters
Type Name Description
IndexSearcher referenceToRefresh
Returns
Type Description
IndexSearcher
Overrides
Lucene.Net.Search.ReferenceManager<Lucene.Net.Search.IndexSearcher>.RefreshIfNeeded(Lucene.Net.Search.IndexSearcher)
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TryIncRef(IndexSearcher)

Declaration
protected override bool TryIncRef(IndexSearcher reference)
Parameters
Type Name Description
IndexSearcher reference
Returns
Type Description
System.Boolean
Overrides
Lucene.Net.Search.ReferenceManager<Lucene.Net.Search.IndexSearcher>.TryIncRef(Lucene.Net.Search.IndexSearcher)

Implements

System.IDisposable

Extension Methods

See Also