org.apache.hadoop.hive.ql.optimizer

Class ColumnPrunerProcCtx

java.lang.Object

org.apache.hadoop.hive.ql.optimizer.ColumnPrunerProcCtx

All Implemented Interfaces:

NodeProcessorCtx

public class ColumnPrunerProcCtx
extends Object
implements NodeProcessorCtx

This class implements the processor context for Column Pruner.

Constructor Summary

Constructors

Constructor and Description
ColumnPrunerProcCtx(ParseContext pctx)

Method Summary

Modifier and Type	Method and Description
List<FieldNode>	genColLists(Operator<? extends OperatorDesc> curOp) Creates the list of internal column names(represented by field nodes, these names are used in the RowResolver and are different from the external column names) that are needed in the subtree.
List<FieldNode>	genColLists(Operator<? extends OperatorDesc> curOp, Operator<? extends OperatorDesc> child) Creates the list of internal column names (represented by field nodes, these names are used in the RowResolver and are different from the external column names) that are needed in the subtree.
List<FieldNode>	getColsFromSelectExpr(SelectOperator op) Creates the list of internal column names (represented by field nodes) from select expressions in a select operator.
Map<CommonJoinOperator,Map<Byte,List<FieldNode>>>	getJoinPrunedColLists()
ParseContext	getParseContext()
List<FieldNode>	getPrunedColList(Operator<? extends OperatorDesc> op)
Map<Operator<? extends OperatorDesc>,List<FieldNode>>	getPrunedColLists()
List<FieldNode>	getSelectColsFromChildren(SelectOperator op, List<FieldNode> colList) Creates the list of internal column names for select * expressions.
List<FieldNode>	getSelectColsFromLVJoin(RowSchema rs, List<FieldNode> colList) Create the list of internal columns for select tag of LV
void	handleFilterUnionChildren(Operator<? extends OperatorDesc> curOp) If the input filter operator has direct child(ren) which are union operator, and the filter's column is not the same as union's create select operator between them.

Methods inherited from class java.lang.Object

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

Constructor Detail

ColumnPrunerProcCtx

public ColumnPrunerProcCtx(ParseContext pctx)

Method Detail

getParseContext

public ParseContext getParseContext()

getJoinPrunedColLists

public Map<CommonJoinOperator,Map<Byte,List<FieldNode>>> getJoinPrunedColLists()

getPrunedColList

public List<FieldNode> getPrunedColList(Operator<? extends OperatorDesc> op)

getPrunedColLists

public Map<Operator<? extends OperatorDesc>,List<FieldNode>> getPrunedColLists()

genColLists

public List<FieldNode> genColLists(Operator<? extends OperatorDesc> curOp)
                            throws SemanticException

Creates the list of internal column names(represented by field nodes, these names are used in the RowResolver and are different from the external column names) that are needed in the subtree. These columns eventually have to be selected from the table scan.

Parameters:

curOp - The root of the operator subtree.

Returns:

a list of field nodes representing the internal column names.

Throws:

SemanticException

genColLists

public List<FieldNode> genColLists(Operator<? extends OperatorDesc> curOp,
                                   Operator<? extends OperatorDesc> child)
                            throws SemanticException

Creates the list of internal column names (represented by field nodes, these names are used in the RowResolver and are different from the external column names) that are needed in the subtree. These columns eventually have to be selected from the table scan.

Parameters:

curOp - The root of the operator subtree.

child - The consumer.

Returns:

a list of field nodes representing the internal column names.

Throws:

SemanticException

getColsFromSelectExpr

public List<FieldNode> getColsFromSelectExpr(SelectOperator op)

Creates the list of internal column names (represented by field nodes) from select expressions in a select operator. This function is used for the select operator instead of the genColLists function (which is used by the rest of the operators).

Parameters:

op - The select operator.

Returns:

a list of field nodes representing the internal column names.

getSelectColsFromChildren

public List<FieldNode> getSelectColsFromChildren(SelectOperator op,
                                                 List<FieldNode> colList)

Creates the list of internal column names for select * expressions.

Parameters:

op - The select operator.

colList - The list of internal column names (represented by field nodes) returned by the children of the select operator.

Returns:

a list of field nodes representing the internal column names.

getSelectColsFromLVJoin

public List<FieldNode> getSelectColsFromLVJoin(RowSchema rs,
                                               List<FieldNode> colList)
                                        throws SemanticException

Create the list of internal columns for select tag of LV

Throws:

SemanticException

handleFilterUnionChildren

public void handleFilterUnionChildren(Operator<? extends OperatorDesc> curOp)
                               throws SemanticException

If the input filter operator has direct child(ren) which are union operator, and the filter's column is not the same as union's create select operator between them. The select operator has same number of columns as pruned child operator.

Parameters:

curOp - The filter operator which need to handle children.

Throws:

SemanticException