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#pragma once
#include "yql_statistics.h"
#include <util/generic/hash.h>
#include <util/generic/vector.h>
#include <util/generic/string.h>
#include <set>
/**
* The cost function for cost based optimizer currently consists of methods for computing
* both the cost and cardinalities of individual plan operators
*/
namespace NYql {
struct IProviderContext;
enum class EJoinAlgoType {
Undefined,
LookupJoin,
LookupJoinReverse,
MapJoin,
GraceJoin,
StreamLookupJoin, //Right part can be updated during an operation. Used mainly for joining streams with lookup tables. Currently impplemented in Dq by LookupInputTransform
MergeJoin // To be used in YT
};
//StreamLookupJoin is not a subject for CBO and not not included here
static constexpr auto AllJoinAlgos = { EJoinAlgoType::LookupJoin, EJoinAlgoType::LookupJoinReverse, EJoinAlgoType::MapJoin, EJoinAlgoType::GraceJoin, EJoinAlgoType::MergeJoin };
namespace NDq {
/**
* Join column is a struct that records the relation label and
* attribute name, used in join conditions
*/
struct TJoinColumn {
TString RelName{};
TString AttributeName{};
TString AttributeNameWithAliases{};
std::optional<ui32> EquivalenceClass{};
bool IsConstant = false;
TJoinColumn(TString relName, TString attributeName) :
RelName(relName),
AttributeName(attributeName),
AttributeNameWithAliases(attributeName) {}
bool operator == (const TJoinColumn& other) const {
return RelName == other.RelName && AttributeName == other.AttributeName;
}
struct THashFunction
{
size_t operator()(const TJoinColumn& c) const
{
return THash<TString>{}(c.RelName) ^ THash<TString>{}(c.AttributeName);
}
};
};
bool operator < (const TJoinColumn& c1, const TJoinColumn& c2);
} // namespace NDq
} // namespace NYql
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