OnHeapColumnVector

OnHeapColumnVector is a concrete WritableColumnVector that…​FIXME

OnHeapColumnVector is created when:

Allocating Column Vectors — allocateColumns Static Method

OnHeapColumnVector[] allocateColumns(int capacity, StructType schema) (1)
OnHeapColumnVector[] allocateColumns(int capacity, StructField[] fields)

  1. Simply converts StructType to StructField[] and calls the other allocateColumns

allocateColumns creates an array of OnHeapColumnVector for every field (to hold capacity number of elements of the data type per field).

Note

allocateColumns is used when:

  • AggregateHashMap is created

  • InMemoryTableScanExec is requested to createAndDecompressColumn

  • VectorizedParquetRecordReader is requested to initBatch (with ON_HEAP memory mode)

  • OrcColumnarBatchReader is requested to initBatch (with ON_HEAP memory mode)

  • ColumnVectorUtils is requested to convert an iterator of rows into a single ColumnBatch (aka toBatch)

Creating OnHeapColumnVector Instance

OnHeapColumnVector takes the following when created:

  • Number of elements to hold in a vector (aka capacity)

  • Data type of the elements stored

When created, OnHeapColumnVector reserveInternal (for the given capacity) and reset.

reserveInternal Method

void reserveInternal(int newCapacity)
Note
 reserveInternal is part of WritableColumnVector Contract to…​FIXME.

reserveInternal…​FIXME

reserveNewColumn Method

OnHeapColumnVector reserveNewColumn(int capacity, DataType type)
Note
 reserveNewColumn is part of WritableColumnVector Contract to…​FIXME.

reserveNewColumn…​FIXME

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