Package org.apache.druid.segment

Interface RowIdSupplier

All Known Implementing Classes:
FrameColumnSelectorFactory, QueryableIndexColumnSelectorFactory
public interface RowIdSupplier
Returned by ColumnSelectorFactory.getRowIdSupplier(). Allows users of ColumnSelectorFactory to cache objects returned by their selectors.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final long
    INIT
    A number that will never be returned from getRowId().

  • Method Summary

    Modifier and Type
    Method
    Description
    long
    getRowId()
    Returns a number that uniquely identifies the current position of some underlying cursor.

  • Field Details

  • Method Details

    • getRowId

      long getRowId()
      Returns a number that uniquely identifies the current position of some underlying cursor. This is useful for caching: it is safe to assume nothing has changed in the selector as long as the row ID stays the same. Row IDs do not need to be contiguous or monotonic. They need not have any meaning. In particular: they may not be row *numbers* (row number 0 may have any arbitrary row ID). Valid row IDs are always nonnegative.