org.apache.drill.exec.planner.physical

Class HashPrelUtil

java.lang.Object

org.apache.drill.exec.planner.physical.HashPrelUtil

public class HashPrelUtil
extends Object

Contains utility methods for creating hash expression for either distribution (in PartitionSender) or for HashTable.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	HashPrelUtil.HashExpressionCreatorHelper<T> Interface for creating different forms of hash expression types.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DIST_SEED
static String	HASH_EXPR_NAME
static HashPrelUtil.HashExpressionCreatorHelper<LogicalExpression>	HASH_HELPER_LOGICALEXPRESSION Implementation of HashPrelUtil.HashExpressionCreatorHelper for LogicalExpression type.

Constructor Summary

Constructors

Constructor and Description
HashPrelUtil()

Method Summary

Methods

Modifier and Type	Method and Description
static <T> T	createHashBasedPartitionExpression(List<T> distFields, T seed, HashPrelUtil.HashExpressionCreatorHelper<T> helper) Create hash based partition expression based on the given distribution fields.
static <T> T	createHashExpression(List<T> inputExprs, T seed, HashPrelUtil.HashExpressionCreatorHelper<T> helper, boolean hashAsDouble) Create hash expression based on the given input fields.
static LogicalExpression	getHashExpression(List<DrillDistributionTrait.DistributionField> fields, org.apache.calcite.rel.type.RelDataType rowType) Create a distribution hash expression.
static LogicalExpression	getHashExpression(List<LogicalExpression> fields, boolean hashAsDouble) Return a hash expression : hash32(field1, hash32(field2, hash32(field3, 0)));

Methods inherited from class java.lang.Object

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

Field Detail

HASH_EXPR_NAME

public static final String HASH_EXPR_NAME

See Also:

Constant Field Values

DIST_SEED

public static final int DIST_SEED

See Also:

Constant Field Values

HASH_HELPER_LOGICALEXPRESSION

public static HashPrelUtil.HashExpressionCreatorHelper<LogicalExpression> HASH_HELPER_LOGICALEXPRESSION

Implementation of HashPrelUtil.HashExpressionCreatorHelper for LogicalExpression type.

Constructor Detail

HashPrelUtil

public HashPrelUtil()

Method Detail

createHashBasedPartitionExpression

public static <T> T createHashBasedPartitionExpression(List<T> distFields,
                                       T seed,
                                       HashPrelUtil.HashExpressionCreatorHelper<T> helper)

Create hash based partition expression based on the given distribution fields.

Type Parameters:

T - Input and output expression type. Currently it could be either RexNode or LogicalExpression

Parameters:

distFields - Field list based on which the distribution partition expression is constructed.

helper - Implementation of HashPrelUtil.HashExpressionCreatorHelper which is used to create function expressions.

Returns:

createHashExpression

public static <T> T createHashExpression(List<T> inputExprs,
                         T seed,
                         HashPrelUtil.HashExpressionCreatorHelper<T> helper,
                         boolean hashAsDouble)

Create hash expression based on the given input fields.

Type Parameters:

T - Input and output expression type. Currently it could be either RexNode or LogicalExpression

Parameters:

inputExprs - Expression list based on which the hash expression is constructed.

helper - Implementation of HashPrelUtil.HashExpressionCreatorHelper which is used to create function expressions.

hashAsDouble - Whether to use the hash as double function or regular hash64 function.

Returns:

getHashExpression

public static LogicalExpression getHashExpression(List<LogicalExpression> fields,
                                  boolean hashAsDouble)

Return a hash expression : hash32(field1, hash32(field2, hash32(field3, 0)));

getHashExpression

public static LogicalExpression getHashExpression(List<DrillDistributionTrait.DistributionField> fields,
                                  org.apache.calcite.rel.type.RelDataType rowType)

Create a distribution hash expression.

Parameters:

fields - Distribution fields

rowType - Row type

Returns: