Package org.apache.druid.query.groupby.epinephelinae.vector

Interface GroupByVectorColumnSelector

All Known Implementing Classes:

DictionaryBuildingSingleValueStringGroupByVectorColumnSelector, DoubleGroupByVectorColumnSelector, FloatGroupByVectorColumnSelector, LongGroupByVectorColumnSelector, NilGroupByVectorColumnSelector, NullableDoubleGroupByVectorColumnSelector, NullableFloatGroupByVectorColumnSelector, NullableLongGroupByVectorColumnSelector, SingleValueStringGroupByVectorColumnSelector

public interface GroupByVectorColumnSelector

Column processor for groupBy dimensions. Processors may have internal state, such as the dictionary maintained by DictionaryBuildingSingleValueStringGroupByVectorColumnSelector. Callers should assume that the internal state footprint starts out empty (zero bytes) and is also reset to zero on each call to reset(). Each call to writeKeys(org.apache.datasketches.memory.WritableMemory, int, int, int, int) returns the incremental increase in internal state footprint that happened as a result of that particular call.

See Also:

GroupByVectorColumnProcessorFactory, the nonvectorized version

Method Summary

Modifier and Type	Method	Description
int	getGroupingKeySize()	Get the size in bytes of the key parts generated by this column.
void	reset()	Reset any internal state held by this selector.
int	writeKeys(org.apache.datasketches.memory.WritableMemory keySpace, int keySize, int keyOffset, int startRow, int endRow)	Write key parts for this column, from startRow (inclusive) to endRow (exclusive), into keySpace starting at keyOffset.
void	writeKeyToResultRow(MemoryPointer keyMemory, int keyOffset, ResultRow resultRow, int resultRowPosition)	Write key parts for this column into a particular result row.

Method Detail

getGroupingKeySize

int getGroupingKeySize()

Get the size in bytes of the key parts generated by this column.

writeKeys

int writeKeys(org.apache.datasketches.memory.WritableMemory keySpace,
              int keySize,
              int keyOffset,
              int startRow,
              int endRow)

Write key parts for this column, from startRow (inclusive) to endRow (exclusive), into keySpace starting at keyOffset.

Parameters:

keySpace - key memory

keySize - size of the overall key (not just the part for this column)

keyOffset - starting position for the first key part within keySpace

startRow - starting row (inclusive) within the current vector

endRow - ending row (exclusive) within the current vector

Returns:

estimated increase in internal state footprint, in bytes, as a result of this operation. May be zero if memory did not increase as a result of this operation. Will not be negative.

writeKeyToResultRow

void writeKeyToResultRow(MemoryPointer keyMemory,
                         int keyOffset,
                         ResultRow resultRow,
                         int resultRowPosition)

Write key parts for this column into a particular result row.

Parameters:

keyMemory - key memory

keyOffset - starting position for this key part within keyMemory (starting from MemoryPointer.position)

resultRow - result row to receive key parts

resultRowPosition - position within the result row for this key part

reset

void reset()

Reset any internal state held by this selector. After this method is called, any memory previously written by writeKeys(org.apache.datasketches.memory.WritableMemory, int, int, int, int) must be considered unreadable. Calling writeKeyToResultRow(org.apache.druid.query.groupby.epinephelinae.collection.MemoryPointer, int, org.apache.druid.query.groupby.ResultRow, int) on that memory has undefined behavior.