Package org.apache.lucene.index

Class OrdinalMap

java.lang.Object
org.apache.lucene.index.OrdinalMap
All Implemented Interfaces:
Accountable
public class OrdinalMap extends Object implements Accountable
Maps per-segment ordinals to/from global ordinal space, using a compact packed-ints representation.

NOTE: this is a costly operation, as it must merge sort all terms, and may require non-trivial RAM once done. It's better to operate in segment-private ordinal space instead when possible.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

  • Field Details

  • Method Details

    • build

      public static OrdinalMap build(IndexReader.CacheKey owner, SortedDocValues[] values, float acceptableOverheadRatio) throws IOException
      Create an ordinal map that uses the number of unique values of each SortedDocValues instance as a weight.
      Throws:
      IOException
      See Also:

    • build

      public static OrdinalMap build(IndexReader.CacheKey owner, SortedSetDocValues[] values, float acceptableOverheadRatio) throws IOException
      Create an ordinal map that uses the number of unique values of each SortedSetDocValues instance as a weight.
      Throws:
      IOException
      See Also:

    • build

      public static OrdinalMap build(IndexReader.CacheKey owner, TermsEnum[] subs, long[] weights, float acceptableOverheadRatio) throws IOException
      Creates an ordinal map that allows mapping ords to/from a merged space from subs.
      Parameters:
      owner - a cache key
      subs - TermsEnums that support TermsEnum.ord(). They need not be dense (e.g. can be FilteredTermsEnums}.
      weights - a weight for each sub. This is ideally correlated with the number of unique terms that each sub introduces compared to the other subs
      Throws:
      IOException - if an I/O error occurred.

    • getGlobalOrds

      public LongValues getGlobalOrds(int segmentIndex)
      Given a segment number, return a LongValues instance that maps segment ordinals to global ordinals.

    • getFirstSegmentOrd

      public long getFirstSegmentOrd(long globalOrd)
      Given global ordinal, returns the ordinal of the first segment which contains this ordinal (the corresponding to the segment return getFirstSegmentNumber(long)).

    • getFirstSegmentNumber

      public int getFirstSegmentNumber(long globalOrd)
      Given a global ordinal, returns the index of the first segment that contains this term.

    • getValueCount

      public long getValueCount()
      Returns the total number of unique terms in global ord space.

    • ramBytesUsed

      public long ramBytesUsed()
      Description copied from interface: Accountable
      Returns an estimate of the JVM heap memory used by this object in bytes. The method name uses "ram" for historical reasons; only JVM heap memory should be reported. Off-heap resources such as memory-mapped files or native direct buffers should not be included. Negative values are illegal.
      Specified by:
      ramBytesUsed in interface Accountable

    • getChildResources

      public Collection<Accountable> getChildResources()
      Description copied from interface: Accountable
      Returns nested resources of this class. The result should be a point-in-time snapshot (to avoid race conditions).
      Specified by:
      getChildResources in interface Accountable
      See Also: