An IndexKey stores references to a few data (Datum objects) that comprise a key tuple to in an index. More...

#include <index/IndexKey.h>

Public Member Functions
UniqueIndexKey	Copy () const
	Makes a copy of the index key in a newly allocated buffer. More...

void	CopyTo (IndexKey *key2) const
	Makes a copy of the index key to an existing index key. More...

void	DeepCopy (const Schema *sch, std::vector< Datum > &data_buffer)
	Makes a deep copy of all the variable-length Datum the key is refernecing in a newly allocated memory space and append any deep copied Datum into the `data_buffer`. More...

FieldId	GetNumKeys () const
	Returns the number of keys in this IndexKey. More...

DatumRef &	GetKey (FieldId keyid) const
	Returns the key `keyid`. More...

template<class SomeDatum >
void	SetKey (FieldId keyid, const SomeDatum &key)
	Sets the `keyid`-th field in this index key. More...

bool	IsNull (FieldId keyid) const
	Returns the key `keyid` is null. More...

void	SetNullBit (FieldId keyid, bool isnull) const
	Sets or clears the null bit for the key \keyid. More...

bool	HasAnyNull () const
	Returns if any of the keys is null. More...

size_t	GetStructSize () const
	Returns the minimum size of the byte array to store this IndexKey. More...

NullableDatumRef	GetNullableKey (FieldId keyid) const
	Returns the key \keyid as a NullableDatumRef. More...

std::vector< NullableDatumRef >	ToNullableDatumVector () const
	Returns the IndexKey as an std::vector<NullableDatumRef>. More...

	IndexKey (const IndexKey &)=delete

	IndexKey (IndexKey &&)=delete

IndexKey &	operator= (const IndexKey &)=delete

IndexKey &	operator= (IndexKey &&)=delete

Static Public Member Functions
template<class SomeDatum >
static UniqueIndexKey	Create (const std::vector< SomeDatum > &data)
	Allocates and constructs a new IndexKey that references the `data`. More...

template<class SomeDatum >
static UniqueIndexKey	Create (SomeDatum *data, FieldId nkeys)

template<class SomeDatum >
static void	Construct (void *key, const std::vector< SomeDatum > &data)
	Constructs a new IndexKey that references the `data` on a preallocated `key`. More...

template<class SomeDatum >
static void	Construct (void key, SomeDatum data, FieldId nkeys)

static size_t	ComputeStructSize (FieldId nkeys)
	Computes the minimum size of an byte array to store this IndexKey that holds `nkeys`. More...

Static Private Member Functions
template<class SomeDatum >
static void	ConstructImpl (void key, SomeDatum data, FieldId nkeys, size_t sz)

Private Attributes
uint64_t	m_data [1]

Detailed Description

An IndexKey stores references to a few data (Datum objects) that comprise a key tuple to in an index.

It is a plain byte array and may be trivially destructed. When the IndexKey is used, any Datum it references must remain alive.

IndexKey provides both a creation function Create() and an inplace construction function Construct(), which are analogous to c++ new and in place new expressions. See the function docs for details.

One may also use IndexKey to construct a partial search key, where the number of fields is smaller than the key schema does in an index. Any key after the last key in this IndexKey is treated as NULL.

Under the hood, IndexKey stores a 2-byte FieldId as a header, and a null bitmap that immediately follows. Following that is some padding to 8-byte address and an array of 8-byte DatumRef. The main benefit of using IndexKey instead of std::vector<NullableDatumRef> is that it is more compact in space and is likely to be more efficient to access.

Constructor & Destructor Documentation

◆ IndexKey() [1/2]

taco::IndexKey::IndexKey ( const IndexKey & )

delete

◆ IndexKey() [2/2]

taco::IndexKey::IndexKey ( IndexKey && )

delete

Member Function Documentation

◆ ComputeStructSize()

static size_t taco::IndexKey::ComputeStructSize ( FieldId nkeys )

inlinestatic

Computes the minimum size of an byte array to store this IndexKey that holds nkeys.

◆ Construct() [1/2]

template<class SomeDatum >

static void taco::IndexKey::Construct	(	void *	key,
		const std::vector< SomeDatum > &	data
	)

inlinestatic

Constructs a new IndexKey that references the data on a preallocated key.

The key pointer must be aligned to 8-byte address and it is undefined if the size of key is smaller than IndexKey::GetStructSize(data.size()). However, it is safe to construct an IndexKey with fewer keys than allocated.

This is useful for reusing the same space for different keys during iteration in an index.

◆ Construct() [2/2]

template<class SomeDatum >

static void taco::IndexKey::Construct	(	void *	key,
		SomeDatum *	data,
		FieldId	nkeys
	)

inlinestatic

◆ ConstructImpl()

template<class SomeDatum >

static void taco::IndexKey::ConstructImpl	(	void *	key,
		SomeDatum *	data,
		FieldId	nkeys,
		size_t	sz
	)

inlinestaticprivate

◆ Copy()

UniqueIndexKey taco::IndexKey::Copy ( ) const

inline

Makes a copy of the index key in a newly allocated buffer.

The space is exactly enough for storing GetNumKeys() keys.

◆ CopyTo()

void taco::IndexKey::CopyTo ( IndexKey * key2 ) const

inline

Makes a copy of the index key to an existing index key.

The existing index key must be large enough to hold at least as many fields as this index key object. This function does not allocate new space.

It is undefined if the buffer pointed by key2 is not large enough and it is undefined if key2 == this.

◆ Create() [1/2]

template<class SomeDatum >

static UniqueIndexKey taco::IndexKey::Create ( const std::vector< SomeDatum > & data )

inlinestatic

Allocates and constructs a new IndexKey that references the data.

The key has exactly enough space to hold data.size() Datum references.

◆ Create() [2/2]

template<class SomeDatum >

static UniqueIndexKey taco::IndexKey::Create	(	SomeDatum *	data,
		FieldId	nkeys
	)

inlinestatic

◆ DeepCopy()

void taco::IndexKey::DeepCopy	(	const Schema *	sch,
		std::vector< Datum > &	data_buffer
	)

inline

Makes a deep copy of all the variable-length Datum the key is refernecing in a newly allocated memory space and append any deep copied Datum into the data_buffer.

Then it replaces the old DataRef with the new ones that references the new Datum in data_buffer in this IndexKey. The caller should ensure data_buffer is alive when the returned IndexKey is accessed.

It is undefined if GetNumKeys() > sch->GetNumFields().

◆ GetKey()

DatumRef& taco::IndexKey::GetKey ( FieldId keyid ) const

inline

Returns the key keyid.

It is undefined if keyid >= GetNumKeys().

Note that it is possible to set the returned reference provided that it does not change the nullness of the field. Use IndexKey::SetKey() instead if the nullness of the field can change.

◆ GetNullableKey()

NullableDatumRef taco::IndexKey::GetNullableKey ( FieldId keyid ) const

inline

Returns the key \keyid as a NullableDatumRef.

◆ GetNumKeys()

FieldId taco::IndexKey::GetNumKeys ( ) const

inline

Returns the number of keys in this IndexKey.

◆ GetStructSize()

size_t taco::IndexKey::GetStructSize ( ) const

inline

Returns the minimum size of the byte array to store this IndexKey.

Same as ComputeStructSize(this->GetNumKeys()).

◆ HasAnyNull()

bool taco::IndexKey::HasAnyNull ( ) const

inline

Returns if any of the keys is null.

◆ IsNull()

bool taco::IndexKey::IsNull ( FieldId keyid ) const

inline

Returns the key keyid is null.

Note that it is ok to call IsNull with keyid >= GetNumKeys(). Those keys are treated as NULL.

◆ operator=() [1/2]

IndexKey& taco::IndexKey::operator= ( const IndexKey & )

delete

◆ operator=() [2/2]

IndexKey& taco::IndexKey::operator= ( IndexKey && )

delete

◆ SetKey()

template<class SomeDatum >

void taco::IndexKey::SetKey	(	FieldId	keyid,
		const SomeDatum &	key
	)

inline

Sets the keyid-th field in this index key.

Note that this function cannot be used to increase the number of fields in the index key was allocated with enough space. Use IndexKey::Construct instead for changing the number of fields.

It is undefined if keyid is out of bound.

◆ SetNullBit()

void taco::IndexKey::SetNullBit	(	FieldId	keyid,
		bool	isnull
	)		const

inline

Sets or clears the null bit for the key \keyid.

It is undefined if keyid >= GetNumKeys().

◆ ToNullableDatumVector()

std::vector<NullableDatumRef> taco::IndexKey::ToNullableDatumVector ( ) const

inline

Returns the IndexKey as an std::vector<NullableDatumRef>.

Member Data Documentation

◆ m_data

uint64_t taco::IndexKey::m_data[1]

private

The documentation for this struct was generated from the following file:

index/IndexKey.h

Public Member Functions

Static Public Member Functions

Static Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ IndexKey() [1/2]

◆ IndexKey() [2/2]

Member Function Documentation

◆ ComputeStructSize()

◆ Construct() [1/2]

◆ Construct() [2/2]

◆ ConstructImpl()

◆ Copy()

◆ CopyTo()

◆ Create() [1/2]

◆ Create() [2/2]

◆ DeepCopy()

◆ GetKey()

◆ GetNullableKey()

◆ GetNumKeys()

◆ GetStructSize()

◆ HasAnyNull()

◆ IsNull()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ SetKey()

◆ SetNullBit()

◆ ToNullableDatumVector()

Member Data Documentation

◆ m_data