org.apache.lucene.codecs.memory

## Class DirectPostingsFormat

- java.lang.Object
- - org.apache.lucene.codecs.PostingsFormat
  - - org.apache.lucene.codecs.memory.DirectPostingsFormat

- All Implemented Interfaces:
    NamedSPILoader.NamedSPI

      public final class DirectPostingsFormat
      extends PostingsFormat

  Wraps `Lucene41PostingsFormat` format for on-disk storage, but then at read time loads and stores all terms & postings directly in RAM as byte[], int[].

  WARNING: This is exceptionally RAM intensive: it makes no effort to compress the postings data, storing terms as separate byte[] and postings as separate int[], but as a result it gives substantial increase in search performance.

  This postings format supports `TermsEnum.ord()` and `TermsEnum.seekExact(long)`.

  Because this holds all term bytes as a single byte[], you cannot have more than 2.1GB worth of term bytes in a single segment.

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

- - ### Field Summary

    - ### Fields inherited from class org.apache.lucene.codecs.PostingsFormat

      `EMPTY`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `DirectPostingsFormat()`
    `DirectPostingsFormat(int minSkipCount, int lowFreqCutoff)` minSkipCount is how many terms in a row must have the same prefix before we put a skip pointer down.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `FieldsConsumer` | `fieldsConsumer(SegmentWriteState state)`
    `FieldsProducer` | `fieldsProducer(SegmentReadState state)`

    - ### Methods inherited from class org.apache.lucene.codecs.PostingsFormat

      `availablePostingsFormats, forName, getName, reloadPostingsFormats, toString`

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

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

- - ### Constructor Detail

    - #### DirectPostingsFormat

          public DirectPostingsFormat()

    - #### DirectPostingsFormat

          public DirectPostingsFormat(int minSkipCount,
                              int lowFreqCutoff)

      minSkipCount is how many terms in a row must have the same prefix before we put a skip pointer down. Terms with docFreq <= lowFreqCutoff will use a single int[] to hold all docs, freqs, position and offsets; terms with higher docFreq will use separate arrays.

  - ### Method Detail

    - #### fieldsConsumer

          public FieldsConsumer fieldsConsumer(SegmentWriteState state)
                                        throws IOException

      Specified by:
        `fieldsConsumer` in class `PostingsFormat`
      Throws:
        `IOException`

    - #### fieldsProducer

          public FieldsProducer fieldsProducer(SegmentReadState state)
                                        throws IOException

      Specified by:
        `fieldsProducer` in class `PostingsFormat`
      Throws:
        `IOException`

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