C# Class Lucene.Net.Index.IndexWriter

An IndexWriter creates and maintains an index. The third argument to the constructor determines whether a new index is created, or whether an existing index is opened for the addition of new documents. In either case, documents are added with the addDocument method. When finished adding documents, close should be called.

If an index will not have more documents added for a while and optimal search performance is desired, then the optimize method should be called before the index is closed.

Opening an IndexWriter creates a lock file for the directory in use. Trying to open another IndexWriter on the same directory will lead to an IOException. The IOException is also thrown if an IndexReader on the same directory is used to delete documents from the index.

Mostra file Open project: synhershko/lucene.net Class Usage Examples

Public Properties

Property Type Description
DEFAULT_MAX_BUFFERED_DELETE_TERMS int
DEFAULT_MAX_BUFFERED_DOCS int
MAX_TERM_LENGTH int
WRITE_LOCK_TIMEOUT long

Private Properties

Property Type Description
AcquireRead void
AcquireWrite void
AddMergeException void
ApplyDeletes bool
BlockAddIndexes void
Checkpoint void
Close void
Close void
CloseInternal void
CloseMergeReaders void
Commit void
CommitMerge bool
CommitMergedDeletes void
CommitTransaction void
DoFlush bool
DoFlushInternal bool
DoWait void
EnsureContiguousMerge int
FinishAddIndexes void
FinishCommit void
FinishMerges void
FinishSync void
FlushDocStores bool
GetBufferedDeleteTermsSize int
GetFlushCount int
GetFlushDeletesCount int
GetMaxBufferedDeleteTerms int
GetMaxBufferedDocs int
GetMaxFieldLength int
GetNextExternalMerge MergePolicy.OneMerge
GetNextMerge MergePolicy.OneMerge
GetNumBufferedDeleteTerms int
GetNumBufferedDocuments int
GetRAMBufferSizeMB double
GetSegmentCount int
HandleMergeException void
HandleOOM void
HasExternalSegments bool
IndexWriter System
IndexWriter System
Init void
Init void
InitBlock void
IsClosed bool
IsOpen bool
MaybeMerge void
MaybeMerge void
Merge void
MergeFinish void
MergeInit void
MergeMiddle int
MergeSuccess void
MessageState void
NewSegmentName System.String
NoDupDirs void
NrtIsCurrent bool
OptimizeMergesPending bool
PrepareCommit void
PushMaxBufferedDocs void
RegisterMerge bool
ReleaseRead void
ReleaseWrite void
ResetMergeExceptions void
ResolveExternalSegments void
ResumeAddIndexes void
RollbackInternal void
RollbackTransaction void
SegString System.String
SetDiagnostics void
SetDiagnostics void
SetMergeDocStoreIsCompoundFile void
SetMessageID void
SetRollbackSegmentInfos void
ShouldClose bool
StartCommit void
StartSync bool
StartTransaction void
UpdatePendingMerges void
UpgradeReadToWrite void
WaitForAllSynced bool
_MergeInit void

Public Methods

Method Description
AddDocument ( Lucene.Net.Documents.Document doc ) : void

Adds a document to this index. If the document contains more than SetMaxFieldLength(int) terms for a given field, the remainder are discarded.

Note that if an Exception is hit (for example disk full) then the index will be consistent, but this document may not have been added. Furthermore, it's possible the index will have one segment in non-compound format even when using compound files (when a merge has partially succeeded).

This method periodically flushes pending documents to the Directory (see above), and also periodically triggers segment merges in the index according to the MergePolicy in use.

Merges temporarily consume space in the directory. The amount of space required is up to 1X the size of all segments being merged, when no readers/searchers are open against the index, and up to 2X the size of all segments being merged when readers/searchers are open against the index (see Optimize() for details). The sequence of primitive merge operations performed is governed by the merge policy.

Note that each term in the document can be no longer than 16383 characters, otherwise an IllegalArgumentException will be thrown.

Note that it's possible to create an invalid Unicode string in java if a UTF16 surrogate pair is malformed. In this case, the invalid characters are silently replaced with the Unicode replacement character U+FFFD.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

AddDocument ( Lucene.Net.Documents.Document doc, Lucene.Net.Analysis.Analyzer analyzer ) : void

Adds a document to this index, using the provided analyzer instead of the value of GetAnalyzer(). If the document contains more than SetMaxFieldLength(int) terms for a given field, the remainder are discarded.

See AddDocument(Document) for details on index and IndexWriter state after an Exception, and flushing/merging temporary free space requirements.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

AddIndexes ( ) : void

Merges the provided indexes into this index.

After this completes, the index is optimized.

The provided IndexReaders are not closed.

NOTE: while this is running, any attempts to add or delete documents (with another thread) will be paused until this method completes.

See AddIndexesNoOptimize(Directory[]) for details on transactional semantics, temporary free space required in the Directory, and non-CFS segments on an Exception.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

AddIndexesNoOptimize ( ) : void

Merges all segments from an array of indexes into this index.

This may be used to parallelize batch indexing. A large document collection can be broken into sub-collections. Each sub-collection can be indexed in parallel, on a different thread, process or machine. The complete index can then be created by merging sub-collection indexes with this method.

NOTE: the index in each Directory must not be changed (opened by a writer) while this method is running. This method does not acquire a write lock in each input Directory, so it is up to the caller to enforce this.

NOTE: while this is running, any attempts to add or delete documents (with another thread) will be paused until this method completes.

This method is transactional in how Exceptions are handled: it does not commit a new segments_N file until all indexes are added. This means if an Exception occurs (for example disk full), then either no indexes will have been added or they all will have been.

Note that this requires temporary free space in the Directory up to 2X the sum of all input indexes (including the starting index). If readers/searchers are open against the starting index, then temporary free space required will be higher by the size of the starting index (see Optimize() for details).

Once this completes, the final size of the index will be less than the sum of all input index sizes (including the starting index). It could be quite a bit smaller (if there were many pending deletes) or just slightly smaller.

This requires this index not be among those to be added.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

Commit ( ) : void

Commits all pending changes (added & deleted documents, optimizations, segment merges, added indexes, etc.) to the index, and syncs all referenced index files, such that a reader will see the changes and the index updates will survive an OS or machine crash or power loss. Note that this does not wait for any running background merges to finish. This may be a costly operation, so you should test the cost in your application and do it only when really necessary.

Note that this operation calls Directory.sync on the index files. That call should not return until the file contents & metadata are on stable storage. For FSDirectory, this calls the OS's fsync. But, beware: some hardware devices may in fact cache writes even during fsync, and return before the bits are actually on stable storage, to give the appearance of faster performance. If you have such a device, and it does not have a battery backup (for example) then on power loss it may still lose data. Lucene cannot guarantee consistency on such devices.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

Commit ( string>.IDictionary commitUserData ) : void

Commits all changes to the index, specifying a commitUserData Map (String -> String). This just calls PrepareCommit(IDictionary{string, string}) (if you didn't already call it) and then FinishCommit.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

DeleteAll ( ) : void

Delete all documents in the index.

This method will drop all buffered documents and will remove all segments from the index. This change will not be visible until a Commit() has been called. This method can be rolled back using Rollback().

NOTE: this method is much faster than using deleteDocuments( new MatchAllDocsQuery() ).

NOTE: this method will forcefully abort all merges in progress. If other threads are running Optimize() or any of the addIndexes methods, they will receive MergePolicy.MergeAbortedExceptions.

DeleteDocuments ( ) : void

Deletes the document(s) containing any of the terms. All deletes are flushed at the same time.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

DeleteDocuments ( Lucene.Net.Search.Query query ) : void

Deletes the document(s) matching the provided query.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

DeleteDocuments ( Lucene.Net.Index.Term term ) : void

Deletes the document(s) containing term.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

Dispose ( ) : void

Commits all changes to an index and closes all associated files. Note that this may be a costly operation, so, try to re-use a single writer instead of closing and opening a new one. See Commit() for caveats about write caching done by some IO devices.

If an Exception is hit during close, eg due to disk full or some other reason, then both the on-disk index and the internal state of the IndexWriter instance will be consistent. However, the close will not be complete even though part of it (flushing buffered documents) may have succeeded, so the write lock will still be held.

If you can correct the underlying cause (eg free up some disk space) then you can call close() again. Failing that, if you want to force the write lock to be released (dangerous, because you may then lose buffered docs in the IndexWriter instance) then you can do something like this:

try { writer.close(); } finally { if (IndexWriter.isLocked(directory)) { IndexWriter.unlock(directory); } } after which, you must be certain not to use the writer instance anymore.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer, again. See above for details.

Dispose ( bool waitForMerges ) : void

Closes the index with or without waiting for currently running merges to finish. This is only meaningful when using a MergeScheduler that runs merges in background threads.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer, again. See above for details.

NOTE: it is dangerous to always call close(false), especially when IndexWriter is not open for very long, because this can result in "merge starvation" whereby long merges will never have a chance to finish. This will cause too many segments in your index over time.

ExpungeDeletes ( ) : void

Expunges all deletes from the index. When an index has many document deletions (or updates to existing documents), it's best to either call optimize or expungeDeletes to remove all unused data in the index associated with the deleted documents. To see how many deletions you have pending in your index, call IndexReader.NumDeletedDocs This saves disk space and memory usage while searching. expungeDeletes should be somewhat faster than optimize since it does not insist on reducing the index to a single segment (though, this depends on the MergePolicy; see MergePolicy.FindMergesToExpungeDeletes.). Note that this call does not first commit any buffered documents, so you must do so yourself if necessary. See also ExpungeDeletes(bool)

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

ExpungeDeletes ( bool doWait ) : void

Just like ExpungeDeletes(), except you can specify whether the call should block until the operation completes. This is only meaningful with a MergeScheduler that is able to run merges in background threads.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

Flush ( bool triggerMerge, bool flushDocStores, bool flushDeletes ) : void

Flush all in-memory buffered udpates (adds and deletes) to the Directory.

GetDocCount ( int i ) : int
GetReader ( ) : IndexReader

Expert: returns a readonly reader, covering all committed as well as un-committed changes to the index. This provides "near real-time" searching, in that changes made during an IndexWriter session can be quickly made available for searching without closing the writer nor calling Commit().

Note that this is functionally equivalent to calling {#commit} and then using IndexReader.Open(string) to open a new reader. But the turarnound time of this method should be faster since it avoids the potentially costly Commit().

You must close the IndexReader returned by this method once you are done using it.

It's near real-time because there is no hard guarantee on how quickly you can get a new reader after making changes with IndexWriter. You'll have to experiment in your situation to determine if it's faster enough. As this is a new and experimental feature, please report back on your findings so we can learn, improve and iterate.

The resulting reader suppports IndexReader.Reopen() , but that call will simply forward back to this method (though this may change in the future).

The very first time this method is called, this writer instance will make every effort to pool the readers that it opens for doing merges, applying deletes, etc. This means additional resources (RAM, file descriptors, CPU time) will be consumed.

For lower latency on reopening a reader, you should call SetMergedSegmentWarmer to call SetMergedSegmentWarmer to pre-warm a newly merged segment before it's committed to the index. This is important for minimizing index-to-search delay after a large merge.

If an addIndexes* call is running in another thread, then this reader will only search those segments from the foreign index that have been successfully copied over, so far

.

NOTE: Once the writer is closed, any outstanding readers may continue to be used. However, if you attempt to reopen any of those readers, you'll hit an AlreadyClosedException.

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

GetReader ( int termInfosIndexDivisor ) : IndexReader

Expert: like GetReader(), except you can specify which termInfosIndexDivisor should be used for any newly opened readers.

HasDeletions ( ) : bool
IndexWriter ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, IndexDeletionPolicy deletionPolicy, MaxFieldLength mfl ) : System

Expert: constructs an IndexWriter with a custom IndexDeletionPolicy , for the index in d, first creating it if it does not already exist. Text will be analyzed with a.

has this index open (write.lock could not be obtained)

read/written to or if there is any other low-level IO error

IndexWriter ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, IndexDeletionPolicy deletionPolicy, MaxFieldLength mfl, IndexCommit commit ) : System

Expert: constructs an IndexWriter on specific commit point, with a custom IndexDeletionPolicy, for the index in d. Text will be analyzed with a.

This is only meaningful if you've used a IndexDeletionPolicy in that past that keeps more than just the last commit.

This operation is similar to Rollback(), except that method can only rollback what's been done with the current instance of IndexWriter since its last commit, whereas this method can rollback to an arbitrary commit point from the past, assuming the IndexDeletionPolicy has preserved past commits.

has this index open (write.lock could not be obtained)

if it does not exist and create is false or if there is any other low-level IO error

IndexWriter ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, MaxFieldLength mfl ) : System

Constructs an IndexWriter for the index in d, first creating it if it does not already exist.

has this index open (write.lock could not be obtained)

read/written to or if there is any other low-level IO error

IndexWriter ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, bool create, IndexDeletionPolicy deletionPolicy, MaxFieldLength mfl ) : System

Expert: constructs an IndexWriter with a custom IndexDeletionPolicy , for the index in d. Text will be analyzed with a. If create is true, then a new, empty index will be created in d, replacing the index already there, if any.

has this index open (write.lock could not be obtained)

if it does not exist and create is false or if there is any other low-level IO error

IndexWriter ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, bool create, MaxFieldLength mfl ) : System

Constructs an IndexWriter for the index in d. Text will be analyzed with a. If create is true, then a new, empty index will be created in d, replacing the index already there, if any.

has this index open (write.lock could not be obtained)

if it does not exist and create is false or if there is any other low-level IO error

IsLocked ( Lucene.Net.Store.Directory directory ) : bool

Returns true iff the index in the named directory is currently locked.

MaxDoc ( ) : int

Returns total number of docs in this index, including docs not yet flushed (still in the RAM buffer), not counting deletions.

MaybeMerge ( ) : void

Expert: asks the mergePolicy whether any merges are necessary now and if so, runs the requested merges and then iterate (test again if merges are needed) until no more merges are returned by the mergePolicy. Explicit calls to maybeMerge() are usually not necessary. The most common case is when merge policy parameters have changed.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

Merge_ForNUnit ( MergePolicy merge ) : void
Message ( System message ) : void

Prints a message to the infoStream (if non-null), prefixed with the identifying information for this writer and the thread that's calling it.

NewestSegment ( ) : SegmentInfo
NumDeletedDocs ( SegmentInfo info ) : int

Obtain the number of deleted docs for a pooled reader. If the reader isn't being pooled, the segmentInfo's delCount is returned.

NumDocs ( ) : int

Returns total number of docs in this index, including docs not yet flushed (still in the RAM buffer), and including deletions. NOTE: buffered deletions are not counted. If you really need these to be counted you should call Commit() first.

NumRamDocs ( ) : int

Expert: Return the number of documents currently buffered in RAM.

Optimize ( ) : void

Requests an "optimize" operation on an index, priming the index for the fastest available search. Traditionally this has meant merging all segments into a single segment as is done in the default merge policy, but individaul merge policies may implement optimize in different ways.

It is recommended that this method be called upon completion of indexing. In environments with frequent updates, optimize is best done during low volume times, if at all.

See http://www.gossamer-threads.com/lists/lucene/java-dev/47895 for more discussion.

Note that optimize requires 2X the index size free space in your Directory (3X if you're using compound file format). For example, if your index size is 10 MB then you need 20 MB free for optimize to complete (30 MB if you're using compound fiel format).

If some but not all readers re-open while an optimize is underway, this will cause > 2X temporary space to be consumed as those new readers will then hold open the partially optimized segments at that time. It is best not to re-open readers while optimize is running.

The actual temporary usage could be much less than these figures (it depends on many factors).

In general, once the optimize completes, the total size of the index will be less than the size of the starting index. It could be quite a bit smaller (if there were many pending deletes) or just slightly smaller.

If an Exception is hit during optimize(), for example due to disk full, the index will not be corrupt and no documents will have been lost. However, it may have been partially optimized (some segments were merged but not all), and it's possible that one of the segments in the index will be in non-compound format even when using compound file format. This will occur when the Exception is hit during conversion of the segment into compound format.

This call will optimize those segments present in the index when the call started. If other threads are still adding documents and flushing segments, those newly created segments will not be optimized unless you call optimize again.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

Optimize ( bool doWait ) : void

Just like Optimize(), except you can specify whether the call should block until the optimize completes. This is only meaningful with a MergeScheduler that is able to run merges in background threads.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

Optimize ( int maxNumSegments ) : void

Optimize the index down to <= maxNumSegments. If maxNumSegments==1 then this is the same as Optimize() .

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

Optimize ( int maxNumSegments, bool doWait ) : void

Just like Optimize(int), except you can specify whether the call should block until the optimize completes. This is only meaningful with a MergeScheduler that is able to run merges in background threads.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

PrepareCommit ( ) : void

Expert: prepare for commit.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

RamSizeInBytes ( ) : long

Expert: Return the total size of all index files currently cached in memory. Useful for size management with flushRamDocs()

Rollback ( ) : void
SegString ( ) : System.String
SetInfoStream ( System infoStream ) : void

If non-null, information about merges, deletes and a message when maxFieldLength is reached will be printed to this.

SetMaxBufferedDeleteTerms ( int maxBufferedDeleteTerms ) : void

Determines the minimal number of delete terms required before the buffered in-memory delete terms are applied and flushed. If there are documents buffered in memory at the time, they are merged and a new segment is created.

Disabled by default (writer flushes by RAM usage).

is enabled but smaller than 1

SetMaxBufferedDocs ( int maxBufferedDocs ) : void

Determines the minimal number of documents required before the buffered in-memory documents are flushed as a new Segment. Large values generally gives faster indexing.

When this is set, the writer will flush every maxBufferedDocs added documents. Pass in DISABLE_AUTO_FLUSH to prevent triggering a flush due to number of buffered documents. Note that if flushing by RAM usage is also enabled, then the flush will be triggered by whichever comes first.

Disabled by default (writer flushes by RAM usage).

enabled but smaller than 2, or it disables maxBufferedDocs when ramBufferSize is already disabled

SetMaxFieldLength ( int maxFieldLength ) : void

The maximum number of terms that will be indexed for a single field in a document. This limits the amount of memory required for indexing, so that collections with very large files will not crash the indexing process by running out of memory. This setting refers to the number of running terms, not to the number of different terms.

Note: this silently truncates large documents, excluding from the index all terms that occur further in the document. If you know your source documents are large, be sure to set this value high enough to accomodate the expected size. If you set it to Integer.MAX_VALUE, then the only limit is your memory, but you should anticipate an OutOfMemoryError.

By default, no more than DEFAULT_MAX_FIELD_LENGTH terms will be indexed for a field.

SetMergePolicy ( MergePolicy mp ) : void

Expert: set the merge policy used by this writer.

SetMergeScheduler ( MergeScheduler mergeScheduler ) : void

Expert: set the merge scheduler used by this writer.

SetRAMBufferSizeMB ( double mb ) : void

Determines the amount of RAM that may be used for buffering added documents and deletions before they are flushed to the Directory. Generally for faster indexing performance it's best to flush by RAM usage instead of document count and use as large a RAM buffer as you can.

When this is set, the writer will flush whenever buffered documents and deletions use this much RAM. Pass in DISABLE_AUTO_FLUSH to prevent triggering a flush due to RAM usage. Note that if flushing by document count is also enabled, then the flush will be triggered by whichever comes first.

NOTE: the account of RAM usage for pending deletions is only approximate. Specifically, if you delete by Query, Lucene currently has no way to measure the RAM usage if individual Queries so the accounting will under-estimate and you should compensate by either calling commit() periodically yourself, or by using SetMaxBufferedDeleteTerms to flush by count instead of RAM usage (each buffered delete Query counts as one).

NOTE: because IndexWriter uses ints when managing its internal storage, the absolute maximum value for this setting is somewhat less than 2048 MB. The precise limit depends on various factors, such as how large your documents are, how many fields have norms, etc., so it's best to set this value comfortably under 2048.

The default value is DEFAULT_RAM_BUFFER_SIZE_MB.

enabled but non-positive, or it disables ramBufferSize when maxBufferedDocs is already disabled

SetSimilarity ( Lucene.Net.Search.Similarity similarity ) : void

Expert: Set the Similarity implementation used by this IndexWriter.

TestPoint ( System name ) : bool
Unlock ( Lucene.Net.Store.Directory directory ) : void

Forcibly unlocks the index in the named directory.

Caution: this should only be used by failure recovery code, when it is known that no other process nor thread is in fact currently accessing this index.

UpdateDocument ( Term term, Lucene.Net.Documents.Document doc ) : void

Updates a document by first deleting the document(s) containing term and then adding the new document. The delete and then add are atomic as seen by a reader on the same index (flush may happen only after the add).

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

UpdateDocument ( Term term, Lucene.Net.Documents.Document doc, Lucene.Net.Analysis.Analyzer analyzer ) : void

Updates a document by first deleting the document(s) containing term and then adding the new document. The delete and then add are atomic as seen by a reader on the same index (flush may happen only after the add).

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

WaitForMerges ( ) : void

Wait for any currently outstanding merges to finish.

It is guaranteed that any merges started prior to calling this method will have completed once this method completes.

Protected Methods

Method Description
Dispose ( bool disposing, bool waitForMerges ) : void
DoAfterFlush ( ) : void

A hook for extending classes to execute operations after pending added and deleted documents have been flushed to the Directory but before the change is committed (new segments_N file written).

DoBeforeFlush ( ) : void

A hook for extending classes to execute operations before pending added and deleted documents are flushed to the Directory.

EnsureOpen ( ) : void
EnsureOpen ( bool includePendingClose ) : void

Used internally to throw an AlreadyClosedException if this IndexWriter has been closed.

Private Methods

Method Description
AcquireRead ( ) : void
AcquireWrite ( ) : void
AddMergeException ( MergePolicy merge ) : void
ApplyDeletes ( ) : bool
BlockAddIndexes ( bool includePendingClose ) : void
Checkpoint ( ) : void
Close ( ) : void
Close ( bool waitForMerges ) : void
CloseInternal ( bool waitForMerges ) : void
CloseMergeReaders ( MergePolicy merge, bool suppressExceptions ) : void
Commit ( long sizeInBytes ) : void
CommitMerge ( MergePolicy merge, SegmentMerger merger, int mergedDocCount, Lucene.Net.Index.SegmentReader mergedReader ) : bool
CommitMergedDeletes ( MergePolicy merge, Lucene.Net.Index.SegmentReader mergeReader ) : void

Carefully merges deletes for the segments we just merged. This is tricky because, although merging will clear all deletes (compacts the documents), new deletes may have been flushed to the segments since the merge was started. This method "carries over" such new deletes onto the newly merged segment, and saves the resulting deletes file (incrementing the delete generation for merge.info). If no deletes were flushed, no new deletes file is saved.

CommitTransaction ( ) : void
DoFlush ( bool flushDocStores, bool flushDeletes ) : bool
DoFlushInternal ( bool flushDocStores, bool flushDeletes ) : bool
DoWait ( ) : void
EnsureContiguousMerge ( MergePolicy merge ) : int
FinishAddIndexes ( ) : void
FinishCommit ( ) : void
FinishMerges ( bool waitForMerges ) : void
FinishSync ( System fileName, bool success ) : void
FlushDocStores ( ) : bool

Tells the docWriter to close its currently open shared doc stores (stored fields & vectors files). Return value specifices whether new doc store files are compound or not.

GetBufferedDeleteTermsSize ( ) : int
GetFlushCount ( ) : int
GetFlushDeletesCount ( ) : int
GetMaxBufferedDeleteTerms ( ) : int
GetMaxBufferedDocs ( ) : int
GetMaxFieldLength ( ) : int
GetNextExternalMerge ( ) : MergePolicy.OneMerge

Like getNextMerge() except only returns a merge if it's external.

GetNextMerge ( ) : MergePolicy.OneMerge

Expert: the MergeScheduler calls this method to retrieve the next merge requested by the MergePolicy

GetNumBufferedDeleteTerms ( ) : int
GetNumBufferedDocuments ( ) : int
GetRAMBufferSizeMB ( ) : double
GetSegmentCount ( ) : int
HandleMergeException ( System t, MergePolicy merge ) : void
HandleOOM ( System oom, System location ) : void
HasExternalSegments ( ) : bool
IndexWriter ( ) : System
IndexWriter ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, bool create, IndexDeletionPolicy deletionPolicy, MaxFieldLength mfl, Lucene.Net.Index.DocumentsWriter.IndexingChain indexingChain, IndexCommit commit ) : System

Expert: constructs an IndexWriter with a custom IndexDeletionPolicy and IndexingChain, for the index in d. Text will be analyzed with a. If create is true, then a new, empty index will be created in d, replacing the index already there, if any.

has this index open (write.lock could not be obtained)

if it does not exist and create is false or if there is any other low-level IO error

Init ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, IndexDeletionPolicy deletionPolicy, int maxFieldLength, Lucene.Net.Index.DocumentsWriter.IndexingChain indexingChain, IndexCommit commit ) : void
Init ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, bool create, IndexDeletionPolicy deletionPolicy, int maxFieldLength, Lucene.Net.Index.DocumentsWriter.IndexingChain indexingChain, IndexCommit commit ) : void
InitBlock ( ) : void
IsClosed ( ) : bool
IsOpen ( bool includePendingClose ) : bool
MaybeMerge ( bool optimize ) : void
MaybeMerge ( int maxNumSegmentsOptimize, bool optimize ) : void
Merge ( MergePolicy merge ) : void

Merges the indicated segments, replacing them in the stack with a single segment.

MergeFinish ( MergePolicy merge ) : void

Does fininishing for a merge, which is fast but holds the synchronized lock on IndexWriter instance.

MergeInit ( MergePolicy merge ) : void

Does initial setup for a merge, which is fast but holds the synchronized lock on IndexWriter instance.

MergeMiddle ( MergePolicy merge ) : int

Does the actual (time-consuming) work of the merge, but without holding synchronized lock on IndexWriter instance

MergeSuccess ( MergePolicy merge ) : void

Hook that's called when the specified merge is complete.

MessageState ( ) : void
NewSegmentName ( ) : System.String
NoDupDirs ( Lucene.Net.Store.Directory dirs ) : void
NrtIsCurrent ( SegmentInfos infos ) : bool
OptimizeMergesPending ( ) : bool

Returns true if any merges in pendingMerges or runningMerges are optimization merges.

PrepareCommit ( string>.IDictionary commitUserData ) : void

Expert: prepare for commit, specifying commitUserData Map (String -> String). This does the first phase of 2-phase commit. This method does all steps necessary to commit changes since this writer was opened: flushes pending added and deleted docs, syncs the index files, writes most of next segments_N file. After calling this you must call either Commit() to finish the commit, or Rollback() to revert the commit and undo all changes done since the writer was opened.

You can also just call Commit(IDictionary{string,string}) directly without prepareCommit first in which case that method will internally call prepareCommit.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

PushMaxBufferedDocs ( ) : void

If we are flushing by doc count (not by RAM usage), and using LogDocMergePolicy then push maxBufferedDocs down as its minMergeDocs, to keep backwards compatibility.

RegisterMerge ( MergePolicy merge ) : bool

Checks whether this merge involves any segments already participating in a merge. If not, this merge is "registered", meaning we record that its segments are now participating in a merge, and true is returned. Else (the merge conflicts) false is returned.

ReleaseRead ( ) : void
ReleaseWrite ( ) : void
ResetMergeExceptions ( ) : void
ResolveExternalSegments ( ) : void
ResumeAddIndexes ( ) : void
RollbackInternal ( ) : void
RollbackTransaction ( ) : void
SegString ( SegmentInfos infos ) : System.String
SetDiagnostics ( SegmentInfo info, System source ) : void
SetDiagnostics ( SegmentInfo info, System source, string>.IDictionary details ) : void
SetMergeDocStoreIsCompoundFile ( MergePolicy merge ) : void
SetMessageID ( System infoStream ) : void
SetRollbackSegmentInfos ( SegmentInfos infos ) : void
ShouldClose ( ) : bool
StartCommit ( long sizeInBytes, string>.IDictionary commitUserData ) : void

Walk through all files referenced by the current segmentInfos and ask the Directory to sync each file, if it wasn't already. If that succeeds, then we prepare a new segments_N file but do not fully commit it.

StartSync ( System fileName, ICollection pending ) : bool
StartTransaction ( bool haveReadLock ) : void
UpdatePendingMerges ( int maxNumSegmentsOptimize, bool optimize ) : void
UpgradeReadToWrite ( ) : void
WaitForAllSynced ( ICollection syncing ) : bool

Blocks until all files in syncing are sync'd

_MergeInit ( MergePolicy merge ) : void

Method Details

AddDocument() public method

Adds a document to this index. If the document contains more than SetMaxFieldLength(int) terms for a given field, the remainder are discarded.

Note that if an Exception is hit (for example disk full) then the index will be consistent, but this document may not have been added. Furthermore, it's possible the index will have one segment in non-compound format even when using compound files (when a merge has partially succeeded).

This method periodically flushes pending documents to the Directory (see above), and also periodically triggers segment merges in the index according to the MergePolicy in use.

Merges temporarily consume space in the directory. The amount of space required is up to 1X the size of all segments being merged, when no readers/searchers are open against the index, and up to 2X the size of all segments being merged when readers/searchers are open against the index (see Optimize() for details). The sequence of primitive merge operations performed is governed by the merge policy.

Note that each term in the document can be no longer than 16383 characters, otherwise an IllegalArgumentException will be thrown.

Note that it's possible to create an invalid Unicode string in java if a UTF16 surrogate pair is malformed. In this case, the invalid characters are silently replaced with the Unicode replacement character U+FFFD.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public AddDocument ( Lucene.Net.Documents.Document doc ) : void
doc Lucene.Net.Documents.Document
return void

AddDocument() public method

Adds a document to this index, using the provided analyzer instead of the value of GetAnalyzer(). If the document contains more than SetMaxFieldLength(int) terms for a given field, the remainder are discarded.

See AddDocument(Document) for details on index and IndexWriter state after an Exception, and flushing/merging temporary free space requirements.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public AddDocument ( Lucene.Net.Documents.Document doc, Lucene.Net.Analysis.Analyzer analyzer ) : void
doc Lucene.Net.Documents.Document
analyzer Lucene.Net.Analysis.Analyzer
return void

AddIndexes() public method

Merges the provided indexes into this index.

After this completes, the index is optimized.

The provided IndexReaders are not closed.

NOTE: while this is running, any attempts to add or delete documents (with another thread) will be paused until this method completes.

See AddIndexesNoOptimize(Directory[]) for details on transactional semantics, temporary free space required in the Directory, and non-CFS segments on an Exception.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public AddIndexes ( ) : void
return void

AddIndexesNoOptimize() public method

Merges all segments from an array of indexes into this index.

This may be used to parallelize batch indexing. A large document collection can be broken into sub-collections. Each sub-collection can be indexed in parallel, on a different thread, process or machine. The complete index can then be created by merging sub-collection indexes with this method.

NOTE: the index in each Directory must not be changed (opened by a writer) while this method is running. This method does not acquire a write lock in each input Directory, so it is up to the caller to enforce this.

NOTE: while this is running, any attempts to add or delete documents (with another thread) will be paused until this method completes.

This method is transactional in how Exceptions are handled: it does not commit a new segments_N file until all indexes are added. This means if an Exception occurs (for example disk full), then either no indexes will have been added or they all will have been.

Note that this requires temporary free space in the Directory up to 2X the sum of all input indexes (including the starting index). If readers/searchers are open against the starting index, then temporary free space required will be higher by the size of the starting index (see Optimize() for details).

Once this completes, the final size of the index will be less than the sum of all input index sizes (including the starting index). It could be quite a bit smaller (if there were many pending deletes) or just slightly smaller.

This requires this index not be among those to be added.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public AddIndexesNoOptimize ( ) : void
return void

Commit() public method

Commits all pending changes (added & deleted documents, optimizations, segment merges, added indexes, etc.) to the index, and syncs all referenced index files, such that a reader will see the changes and the index updates will survive an OS or machine crash or power loss. Note that this does not wait for any running background merges to finish. This may be a costly operation, so you should test the cost in your application and do it only when really necessary.

Note that this operation calls Directory.sync on the index files. That call should not return until the file contents & metadata are on stable storage. For FSDirectory, this calls the OS's fsync. But, beware: some hardware devices may in fact cache writes even during fsync, and return before the bits are actually on stable storage, to give the appearance of faster performance. If you have such a device, and it does not have a battery backup (for example) then on power loss it may still lose data. Lucene cannot guarantee consistency on such devices.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public Commit ( ) : void
return void

Commit() public method

Commits all changes to the index, specifying a commitUserData Map (String -> String). This just calls PrepareCommit(IDictionary{string, string}) (if you didn't already call it) and then FinishCommit.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public Commit ( string>.IDictionary commitUserData ) : void
commitUserData string>.IDictionary
return void

DeleteAll() public method

Delete all documents in the index.

This method will drop all buffered documents and will remove all segments from the index. This change will not be visible until a Commit() has been called. This method can be rolled back using Rollback().

NOTE: this method is much faster than using deleteDocuments( new MatchAllDocsQuery() ).

NOTE: this method will forcefully abort all merges in progress. If other threads are running Optimize() or any of the addIndexes methods, they will receive MergePolicy.MergeAbortedExceptions.

public DeleteAll ( ) : void
return void

DeleteDocuments() public method

Deletes the document(s) containing any of the terms. All deletes are flushed at the same time.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public DeleteDocuments ( ) : void
return void

DeleteDocuments() public method

Deletes the document(s) matching the provided query.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public DeleteDocuments ( Lucene.Net.Search.Query query ) : void
query Lucene.Net.Search.Query the query to identify the documents to be deleted ///
return void

DeleteDocuments() public method

Deletes the document(s) containing term.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public DeleteDocuments ( Lucene.Net.Index.Term term ) : void
term Lucene.Net.Index.Term the term to identify the documents to be deleted ///
return void

Dispose() public method

Commits all changes to an index and closes all associated files. Note that this may be a costly operation, so, try to re-use a single writer instead of closing and opening a new one. See Commit() for caveats about write caching done by some IO devices.

If an Exception is hit during close, eg due to disk full or some other reason, then both the on-disk index and the internal state of the IndexWriter instance will be consistent. However, the close will not be complete even though part of it (flushing buffered documents) may have succeeded, so the write lock will still be held.

If you can correct the underlying cause (eg free up some disk space) then you can call close() again. Failing that, if you want to force the write lock to be released (dangerous, because you may then lose buffered docs in the IndexWriter instance) then you can do something like this:

try { writer.close(); } finally { if (IndexWriter.isLocked(directory)) { IndexWriter.unlock(directory); } } after which, you must be certain not to use the writer instance anymore.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer, again. See above for details.

public Dispose ( ) : void
return void

Dispose() public method

Closes the index with or without waiting for currently running merges to finish. This is only meaningful when using a MergeScheduler that runs merges in background threads.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer, again. See above for details.

NOTE: it is dangerous to always call close(false), especially when IndexWriter is not open for very long, because this can result in "merge starvation" whereby long merges will never have a chance to finish. This will cause too many segments in your index over time.

public Dispose ( bool waitForMerges ) : void
waitForMerges bool if true, this call will block /// until all merges complete; else, it will ask all /// running merges to abort, wait until those merges have /// finished (which should be at most a few seconds), and /// then return. ///
return void

Dispose() protected method

protected Dispose ( bool disposing, bool waitForMerges ) : void
disposing bool
waitForMerges bool
return void

DoAfterFlush() protected method

A hook for extending classes to execute operations after pending added and deleted documents have been flushed to the Directory but before the change is committed (new segments_N file written).
protected DoAfterFlush ( ) : void
return void

DoBeforeFlush() protected method

A hook for extending classes to execute operations before pending added and deleted documents are flushed to the Directory.
protected DoBeforeFlush ( ) : void
return void

EnsureOpen() protected method

protected EnsureOpen ( ) : void
return void

EnsureOpen() protected method

Used internally to throw an AlreadyClosedException if this IndexWriter has been closed.
protected EnsureOpen ( bool includePendingClose ) : void
includePendingClose bool
return void

ExpungeDeletes() public method

Expunges all deletes from the index. When an index has many document deletions (or updates to existing documents), it's best to either call optimize or expungeDeletes to remove all unused data in the index associated with the deleted documents. To see how many deletions you have pending in your index, call IndexReader.NumDeletedDocs This saves disk space and memory usage while searching. expungeDeletes should be somewhat faster than optimize since it does not insist on reducing the index to a single segment (though, this depends on the MergePolicy; see MergePolicy.FindMergesToExpungeDeletes.). Note that this call does not first commit any buffered documents, so you must do so yourself if necessary. See also ExpungeDeletes(bool)

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public ExpungeDeletes ( ) : void
return void

ExpungeDeletes() public method

Just like ExpungeDeletes(), except you can specify whether the call should block until the operation completes. This is only meaningful with a MergeScheduler that is able to run merges in background threads.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public ExpungeDeletes ( bool doWait ) : void
doWait bool
return void

Flush() public method

Flush all in-memory buffered udpates (adds and deletes) to the Directory.
public Flush ( bool triggerMerge, bool flushDocStores, bool flushDeletes ) : void
triggerMerge bool if true, we may merge segments (if /// deletes or docs were flushed) if necessary ///
flushDocStores bool if false we are allowed to keep /// doc stores open to share with the next segment ///
flushDeletes bool whether pending deletes should also /// be flushed ///
return void

GetDocCount() public method

public GetDocCount ( int i ) : int
i int
return int

GetReader() public method

Expert: returns a readonly reader, covering all committed as well as un-committed changes to the index. This provides "near real-time" searching, in that changes made during an IndexWriter session can be quickly made available for searching without closing the writer nor calling Commit().

Note that this is functionally equivalent to calling {#commit} and then using IndexReader.Open(string) to open a new reader. But the turarnound time of this method should be faster since it avoids the potentially costly Commit().

You must close the IndexReader returned by this method once you are done using it.

It's near real-time because there is no hard guarantee on how quickly you can get a new reader after making changes with IndexWriter. You'll have to experiment in your situation to determine if it's faster enough. As this is a new and experimental feature, please report back on your findings so we can learn, improve and iterate.

The resulting reader suppports IndexReader.Reopen() , but that call will simply forward back to this method (though this may change in the future).

The very first time this method is called, this writer instance will make every effort to pool the readers that it opens for doing merges, applying deletes, etc. This means additional resources (RAM, file descriptors, CPU time) will be consumed.

For lower latency on reopening a reader, you should call SetMergedSegmentWarmer to call SetMergedSegmentWarmer to pre-warm a newly merged segment before it's committed to the index. This is important for minimizing index-to-search delay after a large merge.

If an addIndexes* call is running in another thread, then this reader will only search those segments from the foreign index that have been successfully copied over, so far

.

NOTE: Once the writer is closed, any outstanding readers may continue to be used. However, if you attempt to reopen any of those readers, you'll hit an AlreadyClosedException.

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

public GetReader ( ) : IndexReader
return IndexReader

GetReader() public method

Expert: like GetReader(), except you can specify which termInfosIndexDivisor should be used for any newly opened readers.
public GetReader ( int termInfosIndexDivisor ) : IndexReader
termInfosIndexDivisor int Subsambles which indexed /// terms are loaded into RAM. This has the same effect as /// except that setting /// must be done at indexing time while this setting can be /// set per reader. When set to N, then one in every /// N*termIndexInterval terms in the index is loaded into /// memory. By setting this to a value > 1 you can reduce /// memory usage, at the expense of higher latency when /// loading a TermInfo. The default value is 1. Set this /// to -1 to skip loading the terms index entirely. ///
return IndexReader

HasDeletions() public method

public HasDeletions ( ) : bool
return bool

IndexWriter() public method

Expert: constructs an IndexWriter with a custom IndexDeletionPolicy , for the index in d, first creating it if it does not already exist. Text will be analyzed with a. has this index open (write.lock could not be obtained) read/written to or if there is any other low-level IO error
public IndexWriter ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, IndexDeletionPolicy deletionPolicy, MaxFieldLength mfl ) : System
d Lucene.Net.Store.Directory the index directory ///
a Lucene.Net.Analysis.Analyzer the analyzer to use ///
deletionPolicy IndexDeletionPolicy see above ///
mfl MaxFieldLength whether or not to limit field lengths ///
return System

IndexWriter() public method

Expert: constructs an IndexWriter on specific commit point, with a custom IndexDeletionPolicy, for the index in d. Text will be analyzed with a.

This is only meaningful if you've used a IndexDeletionPolicy in that past that keeps more than just the last commit.

This operation is similar to Rollback(), except that method can only rollback what's been done with the current instance of IndexWriter since its last commit, whereas this method can rollback to an arbitrary commit point from the past, assuming the IndexDeletionPolicy has preserved past commits. has this index open (write.lock could not be obtained) if it does not exist and create is false or if there is any other low-level IO error

public IndexWriter ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, IndexDeletionPolicy deletionPolicy, MaxFieldLength mfl, IndexCommit commit ) : System
d Lucene.Net.Store.Directory the index directory ///
a Lucene.Net.Analysis.Analyzer the analyzer to use ///
deletionPolicy IndexDeletionPolicy see above ///
mfl MaxFieldLength whether or not to limit field lengths, value is in number of terms/tokens. See . ///
commit IndexCommit which commit to open ///
return System

IndexWriter() public method

Constructs an IndexWriter for the index in d, first creating it if it does not already exist. has this index open (write.lock could not be obtained) read/written to or if there is any other low-level IO error
public IndexWriter ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, MaxFieldLength mfl ) : System
d Lucene.Net.Store.Directory the index directory ///
a Lucene.Net.Analysis.Analyzer the analyzer to use ///
mfl MaxFieldLength Maximum field length in number of terms/tokens: LIMITED, UNLIMITED, or user-specified /// via the MaxFieldLength constructor. ///
return System

IndexWriter() public method

Expert: constructs an IndexWriter with a custom IndexDeletionPolicy , for the index in d. Text will be analyzed with a. If create is true, then a new, empty index will be created in d, replacing the index already there, if any. has this index open (write.lock could not be obtained) if it does not exist and create is false or if there is any other low-level IO error
public IndexWriter ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, bool create, IndexDeletionPolicy deletionPolicy, MaxFieldLength mfl ) : System
d Lucene.Net.Store.Directory the index directory ///
a Lucene.Net.Analysis.Analyzer the analyzer to use ///
create bool true to create the index or overwrite /// the existing one; false to append to the existing /// index ///
deletionPolicy IndexDeletionPolicy see above ///
mfl MaxFieldLength , whether or not to limit field lengths. Value is in number of terms/tokens ///
return System

IndexWriter() public method

Constructs an IndexWriter for the index in d. Text will be analyzed with a. If create is true, then a new, empty index will be created in d, replacing the index already there, if any. has this index open (write.lock could not be obtained) if it does not exist and create is false or if there is any other low-level IO error
public IndexWriter ( Lucene.Net.Store.Directory d, Lucene.Net.Analysis.Analyzer a, bool create, MaxFieldLength mfl ) : System
d Lucene.Net.Store.Directory the index directory ///
a Lucene.Net.Analysis.Analyzer the analyzer to use ///
create bool true to create the index or overwrite /// the existing one; false to append to the existing /// index ///
mfl MaxFieldLength Maximum field length in number of terms/tokens: LIMITED, UNLIMITED, or user-specified /// via the MaxFieldLength constructor. ///
return System

IsLocked() public static method

Returns true iff the index in the named directory is currently locked.
public static IsLocked ( Lucene.Net.Store.Directory directory ) : bool
directory Lucene.Net.Store.Directory the directory to check for a lock ///
return bool

MaxDoc() public method

Returns total number of docs in this index, including docs not yet flushed (still in the RAM buffer), not counting deletions.
public MaxDoc ( ) : int
return int

MaybeMerge() public method

Expert: asks the mergePolicy whether any merges are necessary now and if so, runs the requested merges and then iterate (test again if merges are needed) until no more merges are returned by the mergePolicy. Explicit calls to maybeMerge() are usually not necessary. The most common case is when merge policy parameters have changed.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public MaybeMerge ( ) : void
return void

Merge_ForNUnit() public method

public Merge_ForNUnit ( MergePolicy merge ) : void
merge MergePolicy
return void

Message() public method

Prints a message to the infoStream (if non-null), prefixed with the identifying information for this writer and the thread that's calling it.
public Message ( System message ) : void
message System
return void

NewestSegment() public method

public NewestSegment ( ) : SegmentInfo
return SegmentInfo

NumDeletedDocs() public method

Obtain the number of deleted docs for a pooled reader. If the reader isn't being pooled, the segmentInfo's delCount is returned.
public NumDeletedDocs ( SegmentInfo info ) : int
info SegmentInfo
return int

NumDocs() public method

Returns total number of docs in this index, including docs not yet flushed (still in the RAM buffer), and including deletions. NOTE: buffered deletions are not counted. If you really need these to be counted you should call Commit() first.
public NumDocs ( ) : int
return int

NumRamDocs() public method

Expert: Return the number of documents currently buffered in RAM.
public NumRamDocs ( ) : int
return int

Optimize() public method

Requests an "optimize" operation on an index, priming the index for the fastest available search. Traditionally this has meant merging all segments into a single segment as is done in the default merge policy, but individaul merge policies may implement optimize in different ways.

It is recommended that this method be called upon completion of indexing. In environments with frequent updates, optimize is best done during low volume times, if at all.

See http://www.gossamer-threads.com/lists/lucene/java-dev/47895 for more discussion.

Note that optimize requires 2X the index size free space in your Directory (3X if you're using compound file format). For example, if your index size is 10 MB then you need 20 MB free for optimize to complete (30 MB if you're using compound fiel format).

If some but not all readers re-open while an optimize is underway, this will cause > 2X temporary space to be consumed as those new readers will then hold open the partially optimized segments at that time. It is best not to re-open readers while optimize is running.

The actual temporary usage could be much less than these figures (it depends on many factors).

In general, once the optimize completes, the total size of the index will be less than the size of the starting index. It could be quite a bit smaller (if there were many pending deletes) or just slightly smaller.

If an Exception is hit during optimize(), for example due to disk full, the index will not be corrupt and no documents will have been lost. However, it may have been partially optimized (some segments were merged but not all), and it's possible that one of the segments in the index will be in non-compound format even when using compound file format. This will occur when the Exception is hit during conversion of the segment into compound format.

This call will optimize those segments present in the index when the call started. If other threads are still adding documents and flushing segments, those newly created segments will not be optimized unless you call optimize again.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public Optimize ( ) : void
return void

Optimize() public method

Just like Optimize(), except you can specify whether the call should block until the optimize completes. This is only meaningful with a MergeScheduler that is able to run merges in background threads.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public Optimize ( bool doWait ) : void
doWait bool
return void

Optimize() public method

Optimize the index down to <= maxNumSegments. If maxNumSegments==1 then this is the same as Optimize() .

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public Optimize ( int maxNumSegments ) : void
maxNumSegments int maximum number of segments left /// in the index after optimization finishes ///
return void

Optimize() public method

Just like Optimize(int), except you can specify whether the call should block until the optimize completes. This is only meaningful with a MergeScheduler that is able to run merges in background threads.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public Optimize ( int maxNumSegments, bool doWait ) : void
maxNumSegments int
doWait bool
return void

PrepareCommit() public method

Expert: prepare for commit.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public PrepareCommit ( ) : void
return void

RamSizeInBytes() public method

Expert: Return the total size of all index files currently cached in memory. Useful for size management with flushRamDocs()
public RamSizeInBytes ( ) : long
return long

Rollback() public method

public Rollback ( ) : void
return void

SegString() public method

public SegString ( ) : System.String
return System.String

SetInfoStream() public method

If non-null, information about merges, deletes and a message when maxFieldLength is reached will be printed to this.
public SetInfoStream ( System infoStream ) : void
infoStream System
return void

SetMaxBufferedDeleteTerms() public method

Determines the minimal number of delete terms required before the buffered in-memory delete terms are applied and flushed. If there are documents buffered in memory at the time, they are merged and a new segment is created.

Disabled by default (writer flushes by RAM usage).

is enabled but smaller than 1

public SetMaxBufferedDeleteTerms ( int maxBufferedDeleteTerms ) : void
maxBufferedDeleteTerms int
return void

SetMaxBufferedDocs() public method

Determines the minimal number of documents required before the buffered in-memory documents are flushed as a new Segment. Large values generally gives faster indexing.

When this is set, the writer will flush every maxBufferedDocs added documents. Pass in DISABLE_AUTO_FLUSH to prevent triggering a flush due to number of buffered documents. Note that if flushing by RAM usage is also enabled, then the flush will be triggered by whichever comes first.

Disabled by default (writer flushes by RAM usage).

enabled but smaller than 2, or it disables maxBufferedDocs when ramBufferSize is already disabled

public SetMaxBufferedDocs ( int maxBufferedDocs ) : void
maxBufferedDocs int
return void

SetMaxFieldLength() public method

The maximum number of terms that will be indexed for a single field in a document. This limits the amount of memory required for indexing, so that collections with very large files will not crash the indexing process by running out of memory. This setting refers to the number of running terms, not to the number of different terms.

Note: this silently truncates large documents, excluding from the index all terms that occur further in the document. If you know your source documents are large, be sure to set this value high enough to accomodate the expected size. If you set it to Integer.MAX_VALUE, then the only limit is your memory, but you should anticipate an OutOfMemoryError.

By default, no more than DEFAULT_MAX_FIELD_LENGTH terms will be indexed for a field.

public SetMaxFieldLength ( int maxFieldLength ) : void
maxFieldLength int
return void

SetMergePolicy() public method

Expert: set the merge policy used by this writer.
public SetMergePolicy ( MergePolicy mp ) : void
mp MergePolicy
return void

SetMergeScheduler() public method

Expert: set the merge scheduler used by this writer.
public SetMergeScheduler ( MergeScheduler mergeScheduler ) : void
mergeScheduler MergeScheduler
return void

SetRAMBufferSizeMB() public method

Determines the amount of RAM that may be used for buffering added documents and deletions before they are flushed to the Directory. Generally for faster indexing performance it's best to flush by RAM usage instead of document count and use as large a RAM buffer as you can.

When this is set, the writer will flush whenever buffered documents and deletions use this much RAM. Pass in DISABLE_AUTO_FLUSH to prevent triggering a flush due to RAM usage. Note that if flushing by document count is also enabled, then the flush will be triggered by whichever comes first.

NOTE: the account of RAM usage for pending deletions is only approximate. Specifically, if you delete by Query, Lucene currently has no way to measure the RAM usage if individual Queries so the accounting will under-estimate and you should compensate by either calling commit() periodically yourself, or by using SetMaxBufferedDeleteTerms to flush by count instead of RAM usage (each buffered delete Query counts as one).

NOTE: because IndexWriter uses ints when managing its internal storage, the absolute maximum value for this setting is somewhat less than 2048 MB. The precise limit depends on various factors, such as how large your documents are, how many fields have norms, etc., so it's best to set this value comfortably under 2048.

The default value is DEFAULT_RAM_BUFFER_SIZE_MB.

enabled but non-positive, or it disables ramBufferSize when maxBufferedDocs is already disabled

public SetRAMBufferSizeMB ( double mb ) : void
mb double
return void

SetSimilarity() public method

Expert: Set the Similarity implementation used by this IndexWriter.
public SetSimilarity ( Lucene.Net.Search.Similarity similarity ) : void
similarity Lucene.Net.Search.Similarity
return void

TestPoint() public method

public TestPoint ( System name ) : bool
name System
return bool

Unlock() public static method

Forcibly unlocks the index in the named directory.

Caution: this should only be used by failure recovery code, when it is known that no other process nor thread is in fact currently accessing this index.

public static Unlock ( Lucene.Net.Store.Directory directory ) : void
directory Lucene.Net.Store.Directory
return void

UpdateDocument() public method

Updates a document by first deleting the document(s) containing term and then adding the new document. The delete and then add are atomic as seen by a reader on the same index (flush may happen only after the add).

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public UpdateDocument ( Term term, Lucene.Net.Documents.Document doc ) : void
term Term the term to identify the document(s) to be /// deleted ///
doc Lucene.Net.Documents.Document the document to be added ///
return void

UpdateDocument() public method

Updates a document by first deleting the document(s) containing term and then adding the new document. The delete and then add are atomic as seen by a reader on the same index (flush may happen only after the add).

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

public UpdateDocument ( Term term, Lucene.Net.Documents.Document doc, Lucene.Net.Analysis.Analyzer analyzer ) : void
term Term the term to identify the document(s) to be /// deleted ///
doc Lucene.Net.Documents.Document the document to be added ///
analyzer Lucene.Net.Analysis.Analyzer the analyzer to use when analyzing the document ///
return void

WaitForMerges() public method

Wait for any currently outstanding merges to finish.

It is guaranteed that any merges started prior to calling this method will have completed once this method completes.

public WaitForMerges ( ) : void
return void

Property Details

DEFAULT_MAX_BUFFERED_DELETE_TERMS public_oe static_oe property

Disabled by default (because IndexWriter flushes by RAM usage by default). Change using SetMaxBufferedDeleteTerms(int).
public static int DEFAULT_MAX_BUFFERED_DELETE_TERMS
return int

DEFAULT_MAX_BUFFERED_DOCS public_oe static_oe property

Disabled by default (because IndexWriter flushes by RAM usage by default). Change using SetMaxBufferedDocs(int).
public static int DEFAULT_MAX_BUFFERED_DOCS
return int

MAX_TERM_LENGTH public_oe static_oe property

Absolute hard maximum length for a term. If a term arrives from the analyzer longer than this length, it is skipped and a message is printed to infoStream, if set (see SetInfoStream).
public static int MAX_TERM_LENGTH
return int

WRITE_LOCK_TIMEOUT public_oe static_oe property

Default value for the write lock timeout (1,000).
public static long WRITE_LOCK_TIMEOUT
return long