org.apache.tajo.plan.rewrite.rules

Class PartitionedTableRewriter

java.lang.Object

org.apache.tajo.plan.rewrite.rules.PartitionedTableRewriter

All Implemented Interfaces:

LogicalPlanRewriteRule

public class PartitionedTableRewriter
extends Object
implements LogicalPlanRewriteRule

Constructor Summary

Constructors

Constructor and Description
PartitionedTableRewriter()

Method Summary

Methods

Modifier and Type	Method and Description
static Tuple	buildTupleFromPartitionPath(Schema partitionColumnSchema, org.apache.hadoop.fs.Path partitionPath, boolean beNullIfFile) Take a look at a column partition path.
String	getName() It returns the rewrite rule name.
boolean	isEligible(OverridableConf queryContext, LogicalPlan plan) This method checks if this rewrite rule can be applied to a given query plan.
LogicalPlan	rewrite(OverridableConf queryContext, LogicalPlan plan) Updates a logical plan and returns an updated logical plan rewritten by this rule.

Methods inherited from class java.lang.Object

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

Constructor Detail

PartitionedTableRewriter

public PartitionedTableRewriter()

Method Detail

getName

public String getName()

Description copied from interface: LogicalPlanRewriteRule

It returns the rewrite rule name. It will be used for debugging and building a optimization history.

Specified by:

getName in interface LogicalPlanRewriteRule

Returns:

The rewrite rule name

isEligible

public boolean isEligible(OverridableConf queryContext,
                 LogicalPlan plan)

Description copied from interface: LogicalPlanRewriteRule

This method checks if this rewrite rule can be applied to a given query plan. For example, the selection push down can not be applied to the query plan without any filter. In such case, it will return false.

Specified by:

isEligible in interface LogicalPlanRewriteRule

plan - The plan to be checked

Returns:

True if this rule can be applied to a given plan. Otherwise, false.

rewrite

public LogicalPlan rewrite(OverridableConf queryContext,
                  LogicalPlan plan)
                    throws PlanningException

Description copied from interface: LogicalPlanRewriteRule

Updates a logical plan and returns an updated logical plan rewritten by this rule. It must be guaranteed that the input logical plan is not modified even after rewrite. In other words, the rewrite has to modify an plan copied from the input plan.

Specified by:

rewrite in interface LogicalPlanRewriteRule

plan - Input logical plan. It will not be modified.

Returns:

The rewritten logical plan.

Throws:

PlanningException

buildTupleFromPartitionPath

public static Tuple buildTupleFromPartitionPath(Schema partitionColumnSchema,
                                org.apache.hadoop.fs.Path partitionPath,
                                boolean beNullIfFile)

Take a look at a column partition path. A partition path consists of a table path part and column values part. This method transforms a partition path into a tuple with a given partition column schema. hdfs://192.168.0.1/tajo/warehouse/table1/col1=abc/col2=def/col3=ghi ^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^ table path part column values part When a file path is given, it can perform two ways depending on beNullIfFile flag. If it is true, it returns NULL when a given path is a file. Otherwise, it returns a built tuple regardless of file or directory.

Parameters:

partitionColumnSchema - The partition column schema

partitionPath - The partition path

beNullIfFile - If true, this method returns NULL when a given path is a file.

Returns:

The tuple transformed from a column values part.