Innodb_trx_scan_state Class Reference

State of a given scan. More...

Public Member Functions
	Innodb_trx_scan_state ()
	~Innodb_trx_scan_state ()=default
scan_pass	get_pass ()
void	prepare_scan ()
	Prepare the scan: Sets the m_scan_pass used by get_pass() to determine which list caller should iterate, and [m_start_trx_id_range, m_end_trx_id_range) range used by trx_in_range(trx), which the caller should use to check if trx is in range. More...
bool	trx_in_range (const trx_t *trx)
	Check if a transaction belongs to the current range. More...

Static Public Attributes
static constexpr trx_id_t	SCAN_RANGE = 256

Private Member Functions
template<typename Trx_list >
bool	prepare_end_of_range (Trx_list &trx_list)

Private Attributes
scan_pass	m_scan_pass
	Current scan pass. More...
uint64_t	m_start_trx_immutable_id_range
	Start of the current range (inclusive). More...
uint64_t	m_end_trx_immutable_id_range
	End of the current range (exclusive). More...

Detailed Description

State of a given scan.

Scans are restartable, and done in multiple calls. Overall, the code scans separately:

• the RW trx list
• the MySQL trx list For each list, the scan is done by ranges of trx_immutable_id(trx) values. Saving the current scan state allows to resume where the previous scan ended. The typical usage is: state.prepare_scan(); for (trx : trx list for state.get_pass() ){ if(state.trx_in_range(trx)){ process trx } } It's callers responsibility to handle that the two lists aren't disjoint. The range of trx_immutable_id(..) values to be included in scan is decided by prepare_scan(..) so that it contains SCAN_RANGE transactions from current list.

Constructor & Destructor Documentation

Innodb_trx_scan_state()

Innodb_trx_scan_state::Innodb_trx_scan_state ( )

inline

~Innodb_trx_scan_state()

Innodb_trx_scan_state::~Innodb_trx_scan_state ( )

default

Member Function Documentation

get_pass()

scan_pass Innodb_trx_scan_state::get_pass ( )

inline

prepare_end_of_range()

template<typename Trx_list >

bool Innodb_trx_scan_state::prepare_end_of_range ( Trx_list &  trx_list )

inlineprivate

prepare_scan()

void Innodb_trx_scan_state::prepare_scan ( )

inline

Prepare the scan: Sets the m_scan_pass used by get_pass() to determine which list caller should iterate, and [m_start_trx_id_range, m_end_trx_id_range) range used by trx_in_range(trx), which the caller should use to check if trx is in range.

The range will contain at most SCAN_RANGE elements. Caller must hold trx_sys->mutex. When there are no more TRX for this pass, advances to the next pass.

trx_in_range()

bool Innodb_trx_scan_state::trx_in_range ( const trx_t *  trx )

inline

Check if a transaction belongs to the current range.

Parameters

[in]

trx

Transaction to evaluate

Returns

True if transaction is within range.

Member Data Documentation

m_end_trx_immutable_id_range

uint64_t Innodb_trx_scan_state::m_end_trx_immutable_id_range

private

End of the current range (exclusive).

m_scan_pass

scan_pass Innodb_trx_scan_state::m_scan_pass

private

Current scan pass.

m_start_trx_immutable_id_range

uint64_t Innodb_trx_scan_state::m_start_trx_immutable_id_range

private

Start of the current range (inclusive).

SCAN_RANGE

constexpr trx_id_t Innodb_trx_scan_state::SCAN_RANGE = 256

staticconstexpr

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

• storage/innobase/handler/p_s.cc