Package org.apache.lucene.index

Class LiveIndexWriterConfig

  • Direct Known Subclasses:
    IndexWriterConfig
    public class LiveIndexWriterConfig
extends java.lang.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

    • Method Detail

      • getAnalyzer

        public Analyzer getAnalyzer()
        Returns the default analyzer to use for indexing documents.

      • setTermIndexInterval

        public LiveIndexWriterConfig setTermIndexInterval​(int interval)
        Expert: set the interval between indexed terms. Large values cause less memory to be used by IndexReader, but slow random-access to terms. Small values cause more memory to be used by an IndexReader, and speed random-access to terms.

        This parameter determines the amount of computation required per query term, regardless of the number of documents that contain that term. In particular, it is the maximum number of other terms that must be scanned before a term is located and its frequency and position information may be processed. In a large index with user-entered query terms, query processing time is likely to be dominated not by term lookup but rather by the processing of frequency and positional data. In a small index or when many uncommon query terms are generated (e.g., by wildcard queries) term lookup may become a dominant cost.

        In particular, numUniqueTerms/interval terms are read into memory by an IndexReader, and, on average, interval/2 terms must be scanned for each random term access.

        Takes effect immediately, but only applies to newly flushed/merged segments.

        NOTE: This parameter does not apply to all PostingsFormat implementations, including the default one in this release. It only makes sense for term indexes that are implemented as a fixed gap between terms. For example, Lucene41PostingsFormat implements the term index instead based upon how terms share prefixes. To configure its parameters (the minimum and maximum size for a block), you would instead use Lucene41PostingsFormat(int, int). which can also be configured on a per-field basis: 

         //customize Lucene41PostingsFormat, passing minBlockSize=50, maxBlockSize=100
 final PostingsFormat tweakedPostings = new Lucene41PostingsFormat(50, 100);
 iwc.setCodec(new Lucene45Codec() {
   @Override
   public PostingsFormat getPostingsFormatForField(String field) {
     if (field.equals("fieldWithTonsOfTerms"))
       return tweakedPostings;
     else
       return super.getPostingsFormatForField(field);
   }
 });
        Note that other implementations may have their own parameters, or no parameters at all.
        See Also:
        IndexWriterConfig.DEFAULT_TERM_INDEX_INTERVAL

      • getTermIndexInterval

        public int getTermIndexInterval()
        Returns the interval between indexed terms.
        See Also:
        setTermIndexInterval(int)

      • setMaxBufferedDeleteTerms

        public LiveIndexWriterConfig setMaxBufferedDeleteTerms​(int maxBufferedDeleteTerms)
        Determines the maximum number of delete-by-term operations that will be buffered before both the buffered in-memory delete terms and queries are applied and flushed.

        Disabled by default (writer flushes by RAM usage).

        NOTE: This setting won't trigger a segment flush.

        Takes effect immediately, but only the next time a document is added, updated or deleted. Also, if you only delete-by-query, this setting has no effect, i.e. delete queries are buffered until the next segment is flushed.

        Throws:
        java.lang.IllegalArgumentException - if maxBufferedDeleteTerms is enabled but smaller than 1
        See Also:
        setRAMBufferSizeMB(double)

      • getMaxBufferedDeleteTerms

        public int getMaxBufferedDeleteTerms()
        Returns the number of buffered deleted terms that will trigger a flush of all buffered deletes if enabled.
        See Also:
        setMaxBufferedDeleteTerms(int)

      • 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() periodically yourself, or by using setMaxBufferedDeleteTerms(int) to flush and apply buffered deletes by count instead of RAM usage (for each buffered delete Query a constant number of bytes is used to estimate RAM usage). Note that enabling setMaxBufferedDeleteTerms(int) will not trigger any segment flushes.

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

      • 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:
        java.lang.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)

      • setReaderTermsIndexDivisor

        public LiveIndexWriterConfig setReaderTermsIndexDivisor​(int divisor)
        Sets the termsIndexDivisor passed to any readers that IndexWriter opens, for example when applying deletes or creating a near-real-time reader in DirectoryReader.open(IndexWriter, boolean). If you pass -1, the terms index won't be loaded by the readers. This is only useful in advanced situations when you will only .next() through all terms; attempts to seek will hit an exception.

        Takes effect immediately, but only applies to readers opened after this call

        NOTE: divisor settings > 1 do not apply to all PostingsFormat implementations, including the default one in this release. It only makes sense for terms indexes that can efficiently re-sample terms at load time.

      • getCodec

        public Codec getCodec()
        Returns the current Codec.

      • getMaxThreadStates

        public int getMaxThreadStates()
        Returns the max number of simultaneous threads that may be indexing documents at once in IndexWriter.

      • getUseCompoundFile

        public boolean getUseCompoundFile()
        Returns true iff the IndexWriter packs newly written segments in a compound file. Default is true.

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object