org.apache.hadoop.hive.ql.optimizer.ppr
Class PartitionPruner

java.lang.Object
  org.apache.hadoop.hive.ql.optimizer.ppr.PartitionPruner

All Implemented Interfaces:

Transform

public class PartitionPruner
extends Object
implements Transform

The transformation step that does partition pruning.

Constructor Summary

PartitionPruner()

Method Summary

static boolean	hasColumnExpr(ExprNodeDesc desc) Whether the expression contains a column node or not.
static boolean	onlyContainsPartnCols(Table tab, ExprNodeDesc expr) Find out whether the condition only contains partitioned columns.
static PrunedPartitionList	prune(Table tab, ExprNodeDesc prunerExpr, HiveConf conf, String alias, Map<String,PrunedPartitionList> prunedPartitionsMap) Get the partition list for the table that satisfies the partition pruner condition.
ParseContext	transform(ParseContext pctx) All transformation steps implement this interface.

Methods inherited from class java.lang.Object

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

Constructor Detail

PartitionPruner

public PartitionPruner()

Method Detail

transform

public ParseContext transform(ParseContext pctx)
                       throws SemanticException

Description copied from interface: Transform

All transformation steps implement this interface.

Specified by:

transform in interface Transform

Parameters:

pctx - input parse context

Returns:

ParseContext

Throws:

SemanticException

onlyContainsPartnCols

public static boolean onlyContainsPartnCols(Table tab,
                                            ExprNodeDesc expr)

Find out whether the condition only contains partitioned columns. Note that if the table is not partitioned, the function always returns true. condition.

Parameters:

tab - the table object

expr - the pruner expression for the table

prune

public static PrunedPartitionList prune(Table tab,
                                        ExprNodeDesc prunerExpr,
                                        HiveConf conf,
                                        String alias,
                                        Map<String,PrunedPartitionList> prunedPartitionsMap)
                                 throws HiveException

Get the partition list for the table that satisfies the partition pruner condition.

Parameters:

tab - the table object for the alias

prunerExpr - the pruner expression for the alias

conf - for checking whether "strict" mode is on.

alias - for generating error message only.

Returns:

the partition list for the table that satisfies the partition pruner condition.

Throws:

HiveException

hasColumnExpr

public static boolean hasColumnExpr(ExprNodeDesc desc)

Whether the expression contains a column node or not.