src/include/optimizer/predtest.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*-------------------------------------------------------------------------
 *
 * predtest.h
 *	  prototypes for predtest.c
 *
 * Portions Copyright (c) 2005-2009, Greenplum inc
 * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $PostgreSQL: pgsql/src/include/optimizer/predtest.h,v 1.4 2006/03/05 15:58:57 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef PREDTEST_H
#define PREDTEST_H

#include "nodes/primnodes.h"
#include "utils/hsearch.h"
#include "utils/memutils.h"

extern bool predicate_implied_by(List *predicate_list,
					 List *restrictinfo_list);
extern bool predicate_refuted_by(List *predicate_list,
					 List *restrictinfo_list);

/***************************************************************************************
 * BEGIN functions and structures for determining a set of possible values from a clause
 */
typedef struct
{
	/**
	 * the set of possible values, if this can be determined from the clause.
	 */
	HTAB *set;

	/**
	 * The memory context that contains the hashtable and its set of possible values
	 */
	MemoryContext memoryContext;

	/**
	 * if true then set should be ignored and instead we know that we don't know anything about the set of values
	 */
	bool isAnyValuePossible;
} PossibleValueSet;

extern PossibleValueSet
DeterminePossibleValueSet( Node *clause, Node *variable);

/* returns a newly allocated list */
extern Node **
GetPossibleValuesAsArray( PossibleValueSet *pvs, int *numValuesOut );

extern void
DeletePossibleValueSetData(PossibleValueSet *pvs);

extern void
InitPossibleValueSetData(PossibleValueSet *pvs);

/**
 * END functions and structures for determining set of possible values from a clause
 ***********************************************************************************
 */

#endif   /* PREDTEST_H */