org.apache.flink.table.planner.delegation.hive

Class HiveParserProjectWindowTrimmer

java.lang.Object

org.apache.flink.table.planner.delegation.hive.HiveParserProjectWindowTrimmer

public class HiveParserProjectWindowTrimmer
extends Object

For the sql with window expression, it will be converted two project nodes by HiveParser. One of is a project node containing all input fields and the corresponding window node, and another is a project node only contains the selected fields.

For example:

 create table src(a int, b int, c int);
 select a, count(b) over(order by a rows between 1 preceding and 1 following) from src;
 

will be converted into the RelNode like:

 LogicalProject(a=[$0], _o_c2=[$4])
  LogicalProject(a=[$0], b=[$1], c=[$2],
  _o_col3=[count($1) over(order by $0 desc nulls last rows between 1 preceding and 1 following)])

 

The project node with window will contain all the fields, some of which are not necessary. And it will remove the redundant nodes in rule ProjectWindowTransposeRule, and adjust the index referred in RexInputRef for it remove some nodes. But it hasn't adjusted the index of lowerBound/upperBound, which then cause problem when try to access the lowerBound/upperBound.

The class's behavior is quite same to ProjectWindowTransposeRule, but also adjusts the index of lowerBound/upperBound.

Constructor Summary

Constructors

Constructor and Description
HiveParserProjectWindowTrimmer()

Method Summary

Modifier and Type	Method and Description
static org.apache.calcite.rel.RelNode	trimProjectWindow(org.apache.calcite.rel.core.Project selectProject, org.apache.calcite.rel.core.Project projectWithWindow, Map<org.apache.calcite.rel.RelNode,HiveParserRowResolver> relToRowResolver, Map<org.apache.calcite.rel.RelNode,Map<String,Integer>> relToHiveColNameCalcitePosMap) Remove the redundant nodes from the project node which contains over window node.

Methods inherited from class java.lang.Object

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

Constructor Detail

HiveParserProjectWindowTrimmer

public HiveParserProjectWindowTrimmer()

Method Detail

trimProjectWindow

public static org.apache.calcite.rel.RelNode trimProjectWindow(org.apache.calcite.rel.core.Project selectProject,
                                                               org.apache.calcite.rel.core.Project projectWithWindow,
                                                               Map<org.apache.calcite.rel.RelNode,HiveParserRowResolver> relToRowResolver,
                                                               Map<org.apache.calcite.rel.RelNode,Map<String,Integer>> relToHiveColNameCalcitePosMap)

Remove the redundant nodes from the project node which contains over window node.

Parameters:

selectProject - the project node contains selected fields in top of the project node with window

projectWithWindow - the project node which contains windows in the end of project expressions.

Returns:

the new project node after trimming