Package org.apache.drill.exec.store.parquet.columnreaders.batchsizing

Class BatchSizingMemoryUtil

java.lang.Object

org.apache.drill.exec.store.parquet.columnreaders.batchsizing.BatchSizingMemoryUtil

public final class BatchSizingMemoryUtil
extends Object

Helper class to assist the Flat Parquet reader build batches which adhere to memory sizing constraints

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	BatchSizingMemoryUtil.ColumnMemoryUsageInfo	A container class to hold a column batch memory usage information.
static final class	BatchSizingMemoryUtil.VectorMemoryUsageInfo	Container class which holds memory usage information about a variable length ValueVector; all values are in bytes.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	BYTE_VALUE_WIDTH	BYTE in-memory width
static final int	DEFAULT_VL_COLUMN_AVG_PRECISION	Default variable length column average precision; computed in such a way that 64k values will fit within one MB to minimize internal fragmentation
static final int	INT_VALUE_WIDTH	INT in-memory width

Method Summary

Modifier and Type	Method	Description
static boolean	canAddNewData(BatchSizingMemoryUtil.ColumnMemoryUsageInfo columnMemoryUsage, long newBitsMemory, long newOffsetsMemory, long newDataMemory)	This method will also load detailed information about this column's current memory usage (with regard to the value vectors).
static long	computeFixedLengthVectorMemory(ParquetColumnMetadata column, int valueCount)
static long	computeVariableLengthVectorMemory(ParquetColumnMetadata column, long averagePrecision, int valueCount)
static int	getAvgVariableLengthColumnTypePrecision(ParquetColumnMetadata column)	This method will return a default value for variable columns; it aims at minimizing internal fragmentation.
static int	getFixedColumnTypePrecision(ParquetColumnMetadata column)
static void	getMemoryUsage(ValueVector sourceVector, int currValueCount, BatchSizingMemoryUtil.VectorMemoryUsageInfo vectorMemoryUsage)	Load memory usage information for a variable length value vector

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

BYTE_VALUE_WIDTH

public static final int BYTE_VALUE_WIDTH

BYTE in-memory width

See Also:

• Constant Field Values

INT_VALUE_WIDTH

public static final int INT_VALUE_WIDTH

INT in-memory width

See Also:

• Constant Field Values

DEFAULT_VL_COLUMN_AVG_PRECISION

public static final int DEFAULT_VL_COLUMN_AVG_PRECISION

Default variable length column average precision; computed in such a way that 64k values will fit within one MB to minimize internal fragmentation

See Also:

• Constant Field Values

Method Details

canAddNewData

public static boolean canAddNewData(BatchSizingMemoryUtil.ColumnMemoryUsageInfo columnMemoryUsage,
 long newBitsMemory,
 long newOffsetsMemory,
 long newDataMemory)

This method will also load detailed information about this column's current memory usage (with regard to the value vectors).

Parameters:

columnMemoryUsage - container which contains column's memory usage information (usage information will be automatically updated by this method)

newBitsMemory - New nullable data which might be inserted when processing a new input chunk

newOffsetsMemory - New offsets data which might be inserted when processing a new input chunk

newDataMemory - New data which might be inserted when processing a new input chunk

Returns:

true if adding the new data will not lead this column's Value Vector go beyond the allowed limit; false otherwise

getMemoryUsage

public static void getMemoryUsage(ValueVector sourceVector,
 int currValueCount,
 BatchSizingMemoryUtil.VectorMemoryUsageInfo vectorMemoryUsage)

Load memory usage information for a variable length value vector

Parameters:

sourceVector - source value vector

currValueCount - current value count

vectorMemoryUsage - result object which contains source vector memory usage information

getFixedColumnTypePrecision

public static int getFixedColumnTypePrecision(ParquetColumnMetadata column)

Parameters:

column - fixed column's metadata

Returns:

column byte precision

getAvgVariableLengthColumnTypePrecision

public static int getAvgVariableLengthColumnTypePrecision(ParquetColumnMetadata column)

This method will return a default value for variable columns; it aims at minimizing internal fragmentation.

Note that the TypeHelper uses a large default value which might not be always appropriate.

Parameters:

column - fixed column's metadata

Returns:

column byte precision

computeFixedLengthVectorMemory

public static long computeFixedLengthVectorMemory(ParquetColumnMetadata column,
 int valueCount)

Parameters:

column - column's metadata

valueCount - number of column values

Returns:

memory size required to store "valueCount" within a value vector

computeVariableLengthVectorMemory

public static long computeVariableLengthVectorMemory(ParquetColumnMetadata column,
 long averagePrecision,
 int valueCount)

Parameters:

column - length column's metadata

averagePrecision - VL column average precision

valueCount - number of column values

Returns:

memory size required to store "valueCount" within a value vector