Used to identify trx uniquely over time. More...

#include <trx0types.h>

Public Member Functions
	trx_guid_t ()=default
	Initializes trx_guid_t object to a value which doesn't match any real transaction. More...

	trx_guid_t (const trx_t &trx)
	Initializes trx_guid_t with data uniquely identifying the transaction represented by trx_t object. More...

bool	operator== (const trx_guid_t &rhs) const
	Checks if two guids represent the same transaction: they refer to the same trx_t struct and it was not reused meanwhile. More...

	operator bool () const
	Checks if the instance is non-empty, i.e. More...

Public Attributes
uint64_t	m_immutable_id {}
	The immutable id of trx_t object - if you have a pointer to trx_t then we guarantee that immutable id of it will not change over time. More...

uint64_t	m_version {}
	As trx_t objects and thus immutable ids can be reused we need also trx's version, which is incremented each time trx_t object gets reused. More...

Detailed Description

Used to identify trx uniquely over time.

Constructor & Destructor Documentation

◆ trx_guid_t() [1/2]

trx_guid_t::trx_guid_t ( )

default

Initializes trx_guid_t object to a value which doesn't match any real transaction.

◆ trx_guid_t() [2/2]

trx_guid_t::trx_guid_t ( const trx_t & trx )

Initializes trx_guid_t with data uniquely identifying the transaction represented by trx_t object.

Parameters

[in] trx the object representing the transaction

Member Function Documentation

◆ operator bool()

trx_guid_t::operator bool ( ) const

inline

Checks if the instance is non-empty, i.e.

was not default-constructed, but rather initialized to correspond to a real trx_t.

Returns: true iff this guid was initialized to match a real transaction

◆ operator==()

bool trx_guid_t::operator== ( const trx_guid_t & rhs ) const

inline

Checks if two guids represent the same transaction: they refer to the same trx_t struct and it was not reused meanwhile.

Parameters

[in] rhs another guid to compare against

Returns: true iff the two guids are equal and thus represent same transaction

Member Data Documentation

◆ m_immutable_id

uint64_t trx_guid_t::m_immutable_id {}

The immutable id of trx_t object - if you have a pointer to trx_t then we guarantee that immutable id of it will not change over time.

Also there are never two trx_t objects at the same time with same immutable id. However it may happen that two different transactions that do not occur at the same time reuse the same trx_t and thus have same immutable id. Use m_version to detect this situation.

◆ m_version

uint64_t trx_guid_t::m_version {}

As trx_t objects and thus immutable ids can be reused we need also trx's version, which is incremented each time trx_t object gets reused.

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

storage/innobase/include/trx0types.h
storage/innobase/trx/trx0trx.cc

Public Member Functions

Public Attributes