Commit_order_trx_dependency_tracker Class Reference

Generate logical timestamps for MTS using COMMIT_ORDER binlog transaction dependency tracking algorithm. More...

#include <rpl_trx_tracking.h>

Public Member Functions
void	get_dependency (THD *thd, bool parallelization_barrier, int64 &sequence_number, int64 &commit_parent)
	Main function that gets the dependencies using the COMMIT_ORDER tracker. More...
void	update_max_committed (int64 sequence_number)
Logical_clock	get_max_committed_transaction ()
int64	step ()
void	rotate ()

Private Attributes
Logical_clock	m_max_committed_transaction
Logical_clock	m_transaction_counter
int64	m_last_blocking_transaction = SEQ_UNINIT

Detailed Description

Generate logical timestamps for MTS using COMMIT_ORDER binlog transaction dependency tracking algorithm.

Tracks dependencies based on the commit order of transactions. The time intervals during which any transaction holds all its locks are tracked (the interval ends just before storage engine commit, when locks are released. For an autocommit transaction it begins just before storage engine prepare. For BEGIN..COMMIT transactions it begins at the end of the last statement before COMMIT). Two transactions are marked as non-conflicting if their respective intervals overlap. In other words, if trx1 appears before trx2 in the binlog, and trx2 had acquired all its locks before trx1 released its locks, then trx2 is marked such that the replica can schedule it in parallel with trx1.

Member Function Documentation

get_dependency()

void Commit_order_trx_dependency_tracker::get_dependency	(	THD *	thd,
		bool	parallelization_barrier,
		int64 &	sequence_number,
		int64 &	commit_parent
	)

Main function that gets the dependencies using the COMMIT_ORDER tracker.

Get the sequence_number for a transaction, and get the last_commit based on parallel committing transactions.

Parameters

[in]	thd	THD of the caller.
[in]	parallelization_barrier	Transaction is blocking and subseqent transactions should depend on it.
[in,out]	sequence_number	sequence_number initialized and returned.
[in,out]	commit_parent	commit_parent to be returned.
[in]	thd	Current THD from which to extract trx context.
[in]	parallelization_barrier	The transaction is a parallelization_barrier and subseqent transactions should depend on it.
[in,out]	sequence_number	Sequence number of current transaction.
[in,out]	commit_parent	Commit_parent of current transaction, pre-filled with the commit_parent calculated by the logical clock logic.

get_max_committed_transaction()

Logical_clock Commit_order_trx_dependency_tracker::get_max_committed_transaction ( )

inline

rotate()

void Commit_order_trx_dependency_tracker::rotate

(

)

step()

int64 Commit_order_trx_dependency_tracker::step

(

)

update_max_committed()

void Commit_order_trx_dependency_tracker::update_max_committed

(

int64

sequence_number

)

Member Data Documentation

m_last_blocking_transaction

int64 Commit_order_trx_dependency_tracker::m_last_blocking_transaction = SEQ_UNINIT

private

m_max_committed_transaction

Logical_clock Commit_order_trx_dependency_tracker::m_max_committed_transaction

private

m_transaction_counter

Logical_clock Commit_order_trx_dependency_tracker::m_transaction_counter

private

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

• sql/rpl_trx_tracking.h
• sql/rpl_trx_tracking.cc