Packages

c

org.apache.spark.sql.execution.window

UnboundedPrecedingWindowFunctionFrame

final class UnboundedPrecedingWindowFunctionFrame extends WindowFunctionFrame

The UnboundPreceding window frame calculates frames with the following SQL form: ... BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW

There is only an upper bound. Very common use cases are for instance running sums or counts (row_number). Technically this is a special case of a sliding window. However a sliding window has to maintain a buffer, and it must do a full evaluation everytime the buffer changes. This is not the case when there is no lower bound, given the additive nature of most aggregates streaming updates and partial evaluation suffice and no buffering is needed.

Linear Supertypes
WindowFunctionFrame, AnyRef, Any
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  1. UnboundedPrecedingWindowFunctionFrame
  2. WindowFunctionFrame
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Instance Constructors

  1. new UnboundedPrecedingWindowFunctionFrame(target: InternalRow, processor: AggregateProcessor, ubound: BoundOrdering)

    target

    to write results to.

    processor

    to calculate the row values with.

    ubound

    comparator used to identify the upper bound of an output row.

Value Members

  1. def currentLowerBound(): Int

    The current lower window bound in the row array (inclusive).

    The current lower window bound in the row array (inclusive).

    This should be called after the current row is updated via write.

    Definition Classes
    UnboundedPrecedingWindowFunctionFrame → WindowFunctionFrame
  2. def currentUpperBound(): Int

    The current row index of the upper window bound in the row array (exclusive)

    The current row index of the upper window bound in the row array (exclusive)

    This should be called after the current row is updated via write.

    Definition Classes
    UnboundedPrecedingWindowFunctionFrame → WindowFunctionFrame
  3. def prepare(rows: ExternalAppendOnlyUnsafeRowArray): Unit

    Prepare the frame for calculating a new partition.

    Prepare the frame for calculating a new partition.

    rows

    to calculate the frame results for.

    Definition Classes
    UnboundedPrecedingWindowFunctionFrame → WindowFunctionFrame
  4. def write(index: Int, current: InternalRow): Unit

    Write the frame columns for the current row to the given target row.

    Write the frame columns for the current row to the given target row.

    Definition Classes
    UnboundedPrecedingWindowFunctionFrame → WindowFunctionFrame