org.apache.lucene.index

## Class LiveIndexWriterConfig

- java.lang.Object
- - org.apache.lucene.index.LiveIndexWriterConfig

- Direct Known Subclasses:
    IndexWriterConfig

      public class LiveIndexWriterConfig
      extends Object

  Holds all the configuration used by `IndexWriter` with few setters for settings that can be changed on an `IndexWriter` instance "live".
  Since:
    4.0

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected boolean` | `checkPendingFlushOnUpdate` if an indexing thread should check for pending flushes on update in order to help out on a full flush
    `protected Codec` | `codec` `Codec` used to write new segments.
    `protected IndexCommit` | `commit` `IndexCommit` that `IndexWriter` is opened on.
    `protected boolean` | `commitOnClose` True if calls to `IndexWriter.close()` should first do a commit.
    `protected IndexDeletionPolicy` | `delPolicy` `IndexDeletionPolicy` controlling when commit points are deleted.
    `protected org.apache.lucene.index.FlushPolicy` | `flushPolicy` `FlushPolicy` to control when segments are flushed.
    `protected org.apache.lucene.index.DocumentsWriterPerThreadPool` | `indexerThreadPool` `DocumentsWriterPerThreadPool` to control how threads are allocated to `DocumentsWriterPerThread`.
    `protected org.apache.lucene.index.DocumentsWriterPerThread.IndexingChain` | `indexingChain` `DocumentsWriterPerThread.IndexingChain` that determines how documents are indexed.
    `protected Sort` | `indexSort` The sort order to use to write merged segments.
    `protected Set<String>` | `indexSortFields` The field names involved in the index sort
    `protected InfoStream` | `infoStream` `InfoStream` for debugging messages.
    `protected MergePolicy` | `mergePolicy` `MergePolicy` for selecting merges.
    `protected MergeScheduler` | `mergeScheduler` `MergeScheduler` to use for running merges.
    `protected IndexWriterConfig.OpenMode` | `openMode` `IndexWriterConfig.OpenMode` that `IndexWriter` is opened with.
    `protected int` | `perThreadHardLimitMB` Sets the hard upper bound on RAM usage for a single segment, after which the segment is forced to flush.
    `protected boolean` | `readerPooling` True if readers should be pooled.
    `protected Similarity` | `similarity` `Similarity` to use when encoding norms.
    `protected String` | `softDeletesField` soft deletes field
    `protected boolean` | `useCompoundFile` True if segment flushes should use compound file format

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Analyzer` | `getAnalyzer()` Returns the default analyzer to use for indexing documents.
    `Codec` | `getCodec()` Returns the current `Codec`.
    `boolean` | `getCommitOnClose()` Returns `true` if `IndexWriter.close()` should first commit before closing.
    `IndexCommit` | `getIndexCommit()` Returns the `IndexCommit` as specified in `IndexWriterConfig.setIndexCommit(IndexCommit)` or the default, `null` which specifies to open the latest index commit point.
    `IndexDeletionPolicy` | `getIndexDeletionPolicy()` Returns the `IndexDeletionPolicy` specified in `IndexWriterConfig.setIndexDeletionPolicy(IndexDeletionPolicy)` or the default `KeepOnlyLastCommitDeletionPolicy`/
    `Sort` | `getIndexSort()` Get the index-time `Sort` order, applied to all (flushed and merged) segments.
    `Set<String>` | `getIndexSortFields()` Returns the field names involved in the index sort
    `InfoStream` | `getInfoStream()` Returns `InfoStream` used for debugging.
    `int` | `getMaxBufferedDocs()` Returns the number of buffered added documents that will trigger a flush if enabled.
    `IndexWriter.IndexReaderWarmer` | `getMergedSegmentWarmer()` Returns the current merged segment warmer.
    `MergePolicy` | `getMergePolicy()` Returns the current MergePolicy in use by this writer.
    `MergeScheduler` | `getMergeScheduler()` Returns the `MergeScheduler` that was set by `IndexWriterConfig.setMergeScheduler(MergeScheduler)`.
    `IndexWriterConfig.OpenMode` | `getOpenMode()` Returns the `IndexWriterConfig.OpenMode` set by `IndexWriterConfig.setOpenMode(OpenMode)`.
    `double` | `getRAMBufferSizeMB()` Returns the value set by `setRAMBufferSizeMB(double)` if enabled.
    `int` | `getRAMPerThreadHardLimitMB()` Returns the max amount of memory each `DocumentsWriterPerThread` can consume until forcefully flushed.
    `boolean` | `getReaderPooling()` Returns `true` if `IndexWriter` should pool readers even if `DirectoryReader.open(IndexWriter)` has not been called.
    `Similarity` | `getSimilarity()` Expert: returns the `Similarity` implementation used by this `IndexWriter`.
    `String` | `getSoftDeletesField()` Returns the soft deletes field or `null` if soft-deletes are disabled.
    `boolean` | `getUseCompoundFile()` Returns `true` iff the `IndexWriter` packs newly written segments in a compound file.
    `boolean` | `isCheckPendingFlushOnUpdate()` Expert: Returns if indexing threads check for pending flushes on update in order to help our flushing indexing buffers to disk
    `LiveIndexWriterConfig` | `setCheckPendingFlushUpdate(boolean checkPendingFlushOnUpdate)` Expert: sets if indexing threads check for pending flushes on update in order to help our flushing indexing buffers to disk.
    `LiveIndexWriterConfig` | `setMaxBufferedDocs(int maxBufferedDocs)` Determines the minimal number of documents required before the buffered in-memory documents are flushed as a new Segment.
    `LiveIndexWriterConfig` | `setMergedSegmentWarmer(IndexWriter.IndexReaderWarmer mergeSegmentWarmer)` Set the merged segment warmer.
    `LiveIndexWriterConfig` | `setMergePolicy(MergePolicy mergePolicy)` Expert: `MergePolicy` is invoked whenever there are changes to the segments in the index.
    `LiveIndexWriterConfig` | `setRAMBufferSizeMB(double ramBufferSizeMB)` Determines the amount of RAM that may be used for buffering added documents and deletions before they are flushed to the Directory.
    `LiveIndexWriterConfig` | `setUseCompoundFile(boolean useCompoundFile)` Sets if the `IndexWriter` should pack newly written segments in a compound file.
    `String` | `toString()`

    - ### Methods inherited from class java.lang.Object

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

- - ### Field Detail

    - #### delPolicy

          protected volatile IndexDeletionPolicy delPolicy

      `IndexDeletionPolicy` controlling when commit points are deleted.

    - #### commit

          protected volatile IndexCommit commit

      `IndexCommit` that `IndexWriter` is opened on.

    - #### openMode

          protected volatile IndexWriterConfig.OpenMode openMode

      `IndexWriterConfig.OpenMode` that `IndexWriter` is opened with.

    - #### similarity

          protected volatile Similarity similarity

      `Similarity` to use when encoding norms.

    - #### mergeScheduler

          protected volatile MergeScheduler mergeScheduler

      `MergeScheduler` to use for running merges.

    - #### indexingChain

          protected volatile org.apache.lucene.index.DocumentsWriterPerThread.IndexingChain indexingChain

      `DocumentsWriterPerThread.IndexingChain` that determines how documents are indexed.

    - #### codec

          protected volatile Codec codec

      `Codec` used to write new segments.

    - #### infoStream

          protected volatile InfoStream infoStream

      `InfoStream` for debugging messages.

    - #### mergePolicy

          protected volatile MergePolicy mergePolicy

      `MergePolicy` for selecting merges.

    - #### indexerThreadPool

          protected volatile org.apache.lucene.index.DocumentsWriterPerThreadPool indexerThreadPool

      `DocumentsWriterPerThreadPool` to control how threads are allocated to `DocumentsWriterPerThread`.

    - #### readerPooling

          protected volatile boolean readerPooling

      True if readers should be pooled.

    - #### flushPolicy

          protected volatile org.apache.lucene.index.FlushPolicy flushPolicy

      `FlushPolicy` to control when segments are flushed.

    - #### perThreadHardLimitMB

          protected volatile int perThreadHardLimitMB

      Sets the hard upper bound on RAM usage for a single segment, after which the segment is forced to flush.

    - #### useCompoundFile

          protected volatile boolean useCompoundFile

      True if segment flushes should use compound file format

    - #### commitOnClose

          protected boolean commitOnClose

      True if calls to `IndexWriter.close()` should first do a commit.

    - #### indexSort

          protected Sort indexSort

      The sort order to use to write merged segments.

    - #### indexSortFields

          protected Set<String> indexSortFields

      The field names involved in the index sort

    - #### checkPendingFlushOnUpdate

          protected volatile boolean checkPendingFlushOnUpdate

      if an indexing thread should check for pending flushes on update in order to help out on a full flush

    - #### softDeletesField

          protected String softDeletesField

      soft deletes field

  - ### Method Detail

    - #### getAnalyzer

          public Analyzer getAnalyzer()

      Returns the default analyzer to use for indexing documents.

    - #### setRAMBufferSizeMB

          public LiveIndexWriterConfig setRAMBufferSizeMB(double ramBufferSizeMB)

      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 `IndexWriterConfig.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.

      The maximum RAM limit is inherently determined by the JVMs available memory. Yet, an `IndexWriter` session can consume a significantly larger amount of memory than the given RAM limit since this limit is just an indicator when to flush memory resident documents to the Directory. Flushes are likely happen concurrently while other threads adding documents to the writer. For application stability the available memory in the JVM should be significantly larger than the RAM buffer used for indexing.

      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 of individual Queries so the accounting will under-estimate and you should compensate by either calling commit() or refresh() periodically yourself.

      NOTE: It's not guaranteed that all memory resident documents are flushed once this limit is exceeded. Depending on the configured `FlushPolicy` only a subset of the buffered documents are flushed and therefore only parts of the RAM buffer is released.

      The default value is `IndexWriterConfig.DEFAULT_RAM_BUFFER_SIZE_MB`.

      Takes effect immediately, but only the next time a document is added, updated or deleted.

      Throws:
        `IllegalArgumentException` - if ramBufferSize is enabled but non-positive, or it disables ramBufferSize when maxBufferedDocs is already disabled
      See Also:
        `IndexWriterConfig.setRAMPerThreadHardLimitMB(int)`

    - #### getRAMBufferSizeMB

          public double getRAMBufferSizeMB()

      Returns the value set by `setRAMBufferSizeMB(double)` if enabled.

    - #### setMaxBufferedDocs

          public LiveIndexWriterConfig setMaxBufferedDocs(int maxBufferedDocs)

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

      When this is set, the writer will flush every maxBufferedDocs added documents. Pass in `IndexWriterConfig.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).

      Takes effect immediately, but only the next time a document is added, updated or deleted.

      Throws:
        `IllegalArgumentException` - if maxBufferedDocs is enabled but smaller than 2, or it disables maxBufferedDocs when ramBufferSize is already disabled
      See Also:
        `setRAMBufferSizeMB(double)`

    - #### getMaxBufferedDocs

          public int getMaxBufferedDocs()

      Returns the number of buffered added documents that will trigger a flush if enabled.
      See Also:
        `setMaxBufferedDocs(int)`

    - #### setMergePolicy

          public LiveIndexWriterConfig setMergePolicy(MergePolicy 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.

      Takes effect on subsequent merge selections. Any merges in flight or any merges already registered by the previous `MergePolicy` are not affected.

    - #### setMergedSegmentWarmer

          public LiveIndexWriterConfig setMergedSegmentWarmer(IndexWriter.IndexReaderWarmer mergeSegmentWarmer)

      Set the merged segment warmer. See `IndexWriter.IndexReaderWarmer`.

      Takes effect on the next merge.

    - #### getMergedSegmentWarmer

          public IndexWriter.IndexReaderWarmer getMergedSegmentWarmer()

      Returns the current merged segment warmer. See `IndexWriter.IndexReaderWarmer`.

    - #### getOpenMode

          public IndexWriterConfig.OpenMode getOpenMode()

      Returns the `IndexWriterConfig.OpenMode` set by `IndexWriterConfig.setOpenMode(OpenMode)`.

    - #### getIndexDeletionPolicy

          public IndexDeletionPolicy getIndexDeletionPolicy()

      Returns the `IndexDeletionPolicy` specified in `IndexWriterConfig.setIndexDeletionPolicy(IndexDeletionPolicy)` or the default `KeepOnlyLastCommitDeletionPolicy`/

    - #### getIndexCommit

          public IndexCommit getIndexCommit()

      Returns the `IndexCommit` as specified in `IndexWriterConfig.setIndexCommit(IndexCommit)` or the default, `null` which specifies to open the latest index commit point.

    - #### getSimilarity

          public Similarity getSimilarity()

      Expert: returns the `Similarity` implementation used by this `IndexWriter`.

    - #### getMergeScheduler

          public MergeScheduler getMergeScheduler()

      Returns the `MergeScheduler` that was set by `IndexWriterConfig.setMergeScheduler(MergeScheduler)`.

    - #### getCodec

          public Codec getCodec()

      Returns the current `Codec`.

    - #### getMergePolicy

          public MergePolicy getMergePolicy()

      Returns the current MergePolicy in use by this writer.
      See Also:
        `IndexWriterConfig.setMergePolicy(MergePolicy)`

    - #### getReaderPooling

          public boolean getReaderPooling()

      Returns `true` if `IndexWriter` should pool readers even if `DirectoryReader.open(IndexWriter)` has not been called.

    - #### getRAMPerThreadHardLimitMB

          public int getRAMPerThreadHardLimitMB()

      Returns the max amount of memory each `DocumentsWriterPerThread` can consume until forcefully flushed.
      See Also:
        `IndexWriterConfig.setRAMPerThreadHardLimitMB(int)`

    - #### getInfoStream

          public InfoStream getInfoStream()

      Returns `InfoStream` used for debugging.
      See Also:
        `IndexWriterConfig.setInfoStream(InfoStream)`

    - #### setUseCompoundFile

          public LiveIndexWriterConfig setUseCompoundFile(boolean useCompoundFile)

      Sets if the `IndexWriter` should pack newly written segments in a compound file. Default is `true`.

      Use `false` for batch indexing with very large ram buffer settings.

      Note: To control compound file usage during segment merges see `MergePolicy.setNoCFSRatio(double)` and `MergePolicy.setMaxCFSSegmentSizeMB(double)`. This setting only applies to newly created segments.

    - #### getUseCompoundFile

          public boolean getUseCompoundFile()

      Returns `true` iff the `IndexWriter` packs newly written segments in a compound file. Default is `true`.

    - #### getCommitOnClose

          public boolean getCommitOnClose()

      Returns `true` if `IndexWriter.close()` should first commit before closing.

    - #### getIndexSort

          public Sort getIndexSort()

      Get the index-time `Sort` order, applied to all (flushed and merged) segments.

    - #### getIndexSortFields

          public Set<String> getIndexSortFields()

      Returns the field names involved in the index sort

    - #### isCheckPendingFlushOnUpdate

          public boolean isCheckPendingFlushOnUpdate()

      Expert: Returns if indexing threads check for pending flushes on update in order to help our flushing indexing buffers to disk
      WARNING: This API is experimental and might change in incompatible ways in the next release.

    - #### setCheckPendingFlushUpdate

          public LiveIndexWriterConfig setCheckPendingFlushUpdate(boolean checkPendingFlushOnUpdate)

      Expert: sets if indexing threads check for pending flushes on update in order to help our flushing indexing buffers to disk. As a consequence, threads calling `DirectoryReader.openIfChanged(DirectoryReader, IndexWriter)` or `IndexWriter.flush()` will be the only thread writing segments to disk unless flushes are falling behind. If indexing is stalled due to too many pending flushes indexing threads will help our writing pending segment flushes to disk.
      WARNING: This API is experimental and might change in incompatible ways in the next release.

    - #### getSoftDeletesField

          public String getSoftDeletesField()

      Returns the soft deletes field or `null` if soft-deletes are disabled. See `IndexWriterConfig.setSoftDeletesField(String)` for details.

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`

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