//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2016 VMware, Inc. or its affiliates.
//
//	@filename:
//		CHint.h
//
//	@doc:
//		Hint configurations
//---------------------------------------------------------------------------
#ifndef GPOPT_CHint_H
#define GPOPT_CHint_H

#include "gpos/base.h"
#include "gpos/common/CRefCount.h"
#include "gpos/memory/CMemoryPool.h"

#define JOIN_ORDER_DP_THRESHOLD ULONG(10)
#define BROADCAST_THRESHOLD ULONG(10000000)
#define PUSH_GROUP_BY_BELOW_SETOP_THRESHOLD ULONG(10)
#define XFORM_BIND_THRESHOLD ULONG(0)
#define SKEW_FACTOR ULONG(0)


namespace gpopt
{
using namespace gpos;

//---------------------------------------------------------------------------
//	@class:
//		CHint
//
//	@doc:
//		Hint configurations
//
//---------------------------------------------------------------------------
class CHint : public CRefCount
{
private:
	ULONG m_ulJoinArityForAssociativityCommutativity;

	ULONG m_ulArrayExpansionThreshold;

	ULONG m_ulJoinOrderDPLimit;

	ULONG m_ulBroadcastThreshold;

	BOOL m_fEnforceConstraintsOnDML;

	ULONG m_ulPushGroupByBelowSetopThreshold;

	ULONG m_ulXform_bind_threshold;

	ULONG m_ulSkewFactor;

public:
	CHint(const CHint &) = delete;

	// ctor
	CHint(ULONG join_arity_for_associativity_commutativity,
		  ULONG array_expansion_threshold, ULONG ulJoinOrderDPLimit,
		  ULONG broadcast_threshold, BOOL enforce_constraint_on_dml,
		  ULONG push_group_by_below_setop_threshold, ULONG xform_bind_threshold,
		  ULONG skew_factor)
		: m_ulJoinArityForAssociativityCommutativity(
			  join_arity_for_associativity_commutativity),
		  m_ulArrayExpansionThreshold(array_expansion_threshold),
		  m_ulJoinOrderDPLimit(ulJoinOrderDPLimit),
		  m_ulBroadcastThreshold(broadcast_threshold),
		  m_fEnforceConstraintsOnDML(enforce_constraint_on_dml),
		  m_ulPushGroupByBelowSetopThreshold(
			  push_group_by_below_setop_threshold),
		  m_ulXform_bind_threshold(xform_bind_threshold),
		  m_ulSkewFactor(skew_factor)
	{
	}

	// Maximum number of relations in an n-ary join operator where ORCA will
	// explore JoinAssociativity and JoinCommutativity transformations.
	// When the number of relations exceed this we'll prune the search space
	// by not pursuing the above mentioned two transformations.
	ULONG
	UlJoinArityForAssociativityCommutativity() const
	{
		return m_ulJoinArityForAssociativityCommutativity;
	}

	// Maximum number of elements in the scalar comparison with an array which
	// will be expanded for constraint derivation. The benefits of using a smaller number
	// are avoiding expensive expansion of constraints in terms of memory and optimization
	// time. This is used to restrict constructs of following types when the constant-array
	// size is greater than threshold:
	// "(expression) scalar op ANY/ALL (array of constants)" OR
	// "(expression1, expression2) scalar op ANY/ALL ((const-x1, const-y1), ... (const-xn, const-yn))"
	ULONG
	UlArrayExpansionThreshold() const
	{
		return m_ulArrayExpansionThreshold;
	}

	// Maximum number of relations in an n-ary join operator where ORCA will
	// explore join ordering via dynamic programming.
	ULONG
	UlJoinOrderDPLimit() const
	{
		return m_ulJoinOrderDPLimit;
	}

	// Maximum number of rows ORCA will broadcast
	ULONG
	UlBroadcastThreshold() const
	{
		return m_ulBroadcastThreshold;
	}

	// If true, ORCA will add Assertion nodes to the plan to enforce CHECK
	// and NOT NULL constraints on inserted/updated values. (Otherwise it
	// is up to the executor to enforce them.)
	BOOL
	FEnforceConstraintsOnDML() const
	{
		return m_fEnforceConstraintsOnDML;
	}

	// Skip CXformPushGbBelowSetOp if set op arity is greater than this
	ULONG
	UlPushGroupByBelowSetopThreshold() const
	{
		return m_ulPushGroupByBelowSetopThreshold;
	}

	// Stop generating alternatives for group expression if bindings exceed this threshold
	ULONG
	UlXformBindThreshold() const
	{
		return m_ulXform_bind_threshold;
	}

	// User defined skew multiplier, multiplied to the skew ratio calculated from 1000 samples
	ULONG
	UlSkewFactor() const
	{
		return m_ulSkewFactor;
	}

	// generate default hint configurations, which disables sort during insert on
	// append only row-oriented partitioned tables by default
	static CHint *
	PhintDefault(CMemoryPool *mp)
	{
		return GPOS_NEW(mp) CHint(
			gpos::int_max, /* join_arity_for_associativity_commutativity */
			gpos::int_max, /* array_expansion_threshold */
			JOIN_ORDER_DP_THRESHOLD,			 /*ulJoinOrderDPLimit*/
			BROADCAST_THRESHOLD,				 /*broadcast_threshold*/
			true,								 /* enforce_constraint_on_dml */
			PUSH_GROUP_BY_BELOW_SETOP_THRESHOLD, /* push_group_by_below_setop_threshold */
			XFORM_BIND_THRESHOLD,				 /* xform_bind_threshold */
			SKEW_FACTOR							 /* skew_factor */
		);
	}

};	// class CHint
}  // namespace gpopt

#endif	// !GPOPT_CHint_H

// EOF