WritableColumnVector¶

WritableColumnVector is an extension of the ColumnVector abstraction for writable in-memory columnar vectors.

WritableColumnVector is used to allocate ColumnVectors for VectorizedParquetRecordReader.

Contract (Subset)¶

reserveInternal¶

void reserveInternal(
  int capacity)

Used when:

• OffHeapColumnVector and OnHeapColumnVector are created
• WritableColumnVector is requested to reserve

reserveNewColumn¶

WritableColumnVector reserveNewColumn(
  int capacity,
  DataType type)

Used when:

• WritableColumnVector is created or requested to reserveDictionaryIds

Implementations¶

• OffHeapColumnVector
• OnHeapColumnVector

Creating Instance¶

WritableColumnVector takes the following to be created:

• Capacity (number of rows to hold in a vector)
• Data type of the rows stored

reserveAdditional¶

void reserveAdditional(
  int additionalCapacity)

reserveAdditional...FIXME

reserveAdditional is used when:

• VectorizedRleValuesReader is requested to readValues

reserveDictionaryIds¶

WritableColumnVector reserveDictionaryIds(
  int capacity)

reserveDictionaryIds...FIXME

reserveDictionaryIds is used when:

• VectorizedColumnReader is requested to readBatch
• DictionaryEncoding.Decoder is requested to decompress

reserve¶

void reserve(
  int requiredCapacity)

reserve...FIXME

reserve is used when:

• ParquetColumnVector is requested to assembleCollection and assembleStruct
• WritableColumnVector is requested to reserveAdditional, reserveDictionaryIds and all the appends

reset¶

void reset()

reset does nothing (noop) when either isConstant or isAllNull is enabled.

reset...FIXME

reset is used when:

• ParquetColumnVector is requested to reset
• VectorizedDeltaByteArrayReader is requested to skipBinary
• OffHeapColumnVector and OnHeapColumnVector are created
• WritableColumnVector is requested to reserveDictionaryIds
• RowToColumnarExec physical operator is requested to doExecuteColumnar