#include "sql/xa.h"
#include <memory>
#include <new>
#include <string>
#include <unordered_map>
#include <utility>
#include "m_ctype.h"
#include "m_string.h"
#include "map_helpers.h"
#include "my_dbug.h"
#include "my_loglevel.h"
#include "my_macros.h"
#include "my_psi_config.h"
#include "my_sys.h"
#include "mysql/components/services/bits/mysql_mutex_bits.h"
#include "mysql/components/services/bits/psi_bits.h"
#include "mysql/components/services/bits/psi_mutex_bits.h"
#include "mysql/components/services/log_builtins.h"
#include "mysql/plugin.h"
#include "mysql/psi/mysql_mutex.h"
#include "mysql/psi/mysql_transaction.h"
#include "mysql/service_mysql_alloc.h"
#include "mysql_com.h"
#include "mysqld_error.h"
#include "scope_guard.h"
#include "sql/auth/sql_security_ctx.h"
#include "sql/binlog.h"
#include "sql/clone_handler.h"
#include "sql/debug_sync.h"
#include "sql/handler.h"
#include "sql/item.h"
#include "sql/log.h"
#include "sql/mdl.h"
#include "sql/mdl_context_backup.h"
#include "sql/mysqld.h"
#include "sql/protocol.h"
#include "sql/psi_memory_key.h"
#include "sql/query_options.h"
#include "sql/rpl_context.h"
#include "sql/rpl_gtid.h"
#include "sql/rpl_handler.h"
#include "sql/rpl_replica_commit_order_manager.h"
#include "sql/sql_class.h"
#include "sql/sql_const.h"
#include "sql/sql_error.h"
#include "sql/sql_lex.h"
#include "sql/sql_list.h"
#include "sql/sql_plugin.h"
#include "sql/sql_table.h"
#include "sql/system_variables.h"
#include "sql/tc_log.h"
#include "sql/transaction.h"
#include "sql/transaction_info.h"
#include "sql/xa/recovery.h"
#include "sql/xa/sql_xa_commit.h"
#include "sql/xa/transaction_cache.h"
#include "sql_string.h"
#include "template_utils.h"
#include "thr_mutex.h"

Functions
static void	attach_native_trx (THD *thd)
	The function restores previously saved storage engine transaction context. More...

std::ostream &	operator<< (std::ostream &out, struct xid_t const &in)

static bool	xarecover_create_mdl_backup (XA_recover_txn &txn, MEM_ROOT *mem_root)

int	ha_recover (Xid_commit_list commit_list, Xa_state_list xa_list)
	Stage of the recovery process where information is collected from the storage engines (SE), merged with information from the transaction coordinator (TC) and transactions states are determined and enforced. More...

bool	xa_trans_force_rollback (THD *thd)
	Rollback the active XA transaction. More...

void	cleanup_trans_state (THD *thd)
	Reset some transaction state information and delete corresponding Transaction_ctx object from cache. More...

std::shared_ptr< Transaction_ctx >	find_trn_for_recover_and_check_its_state (THD thd, xid_t xid_for_trn_in_recover, XID_STATE *xid_state)
	Find XA transaction in cache by its xid value. More...

bool	acquire_mandatory_metadata_locks (THD thd, xid_t detached_xid)
	Acquire Commit metadata lock and all locks acquired by a prepared XA transaction before server was shutdown or terminated. More...

bool	applier_reset_xa_trans (THD *thd)
	This is a specific to "slave" applier collection of standard cleanup actions to reset XA transaction state at the end of XA prepare rather than to do it at the transaction commit, see `ha_commit_one_phase`. More...

bool	detach_native_trx (THD thd, plugin_ref plugin, void )
	The function detaches existing storage engines transaction context from thd. More...

bool	reattach_native_trx (THD thd, plugin_ref plugin, void )
	The function reattaches existing storage engines transaction context to thd. More...

bool	disconnect_native_trx (THD thd, plugin_ref plugin, void )
	Disconnect transaction in SE. More...

bool	thd_holds_xa_transaction (THD *thd)
	Test if the THD session underlying transaction is an externally coordinated (XA) transaction. More...

bool	is_xa_prepare (THD *thd)
	Checks whether or not the underlying statement is an `XA PREPARE`. More...

bool	is_xa_rollback (THD *thd)
	Checks whether or not the underlying statement is an `XA ROLLBACK`. More...

Variables
static const int	MIN_XID_LIST_SIZE = 128

static const int	MAX_XID_LIST_SIZE = 1024 * 128

static const uint	MYSQL_XID_PREFIX_LEN = 8

static const uint	MYSQL_XID_OFFSET = MYSQL_XID_PREFIX_LEN + sizeof(server_id)

static const uint	MYSQL_XID_GTRID_LEN = MYSQL_XID_OFFSET + sizeof(my_xid)

Function Documentation

◆ acquire_mandatory_metadata_locks()

bool acquire_mandatory_metadata_locks	(	THD *	thd,
		xid_t *	detached_xid
	)

Acquire Commit metadata lock and all locks acquired by a prepared XA transaction before server was shutdown or terminated.

Parameters

thd	Thread context
detached_xid	XID value specified by XA COMMIT or XA ROLLBACK that corresponds to a XA transaction generated outside current session context.

Return values

false	Success
true	Failure

◆ applier_reset_xa_trans()

bool applier_reset_xa_trans ( THD * thd )

This is a specific to "slave" applier collection of standard cleanup actions to reset XA transaction state at the end of XA prepare rather than to do it at the transaction commit, see ha_commit_one_phase.

THD of the slave applier is dissociated from a transaction object in engine that continues to exist there.

Parameters

thd	current thread

Returns: the value of is_error()

◆ attach_native_trx()

static void attach_native_trx ( THD * thd )

static

The function restores previously saved storage engine transaction context.

Parameters

thd	Thread context

◆ cleanup_trans_state()

void cleanup_trans_state ( THD * thd )

Reset some transaction state information and delete corresponding Transaction_ctx object from cache.

Parameters

thd	Current thread

◆ detach_native_trx()

bool detach_native_trx	(	THD *	thd,
		plugin_ref	plugin,
		void *
	)

The function detaches existing storage engines transaction context from thd.

Backup area to save it is provided to low level storage engine function.

is invoked by plugin_foreach() after trans_xa_start() for each storage engine.

Parameters

[in,out]	thd	Thread context
	plugin	Reference to handlerton

Returns: false on success, true otherwise.

◆ disconnect_native_trx()

bool disconnect_native_trx	(	THD *	thd,
		plugin_ref	plugin,
		void *
	)

Disconnect transaction in SE.

This the same action which is performed by SE when disconnecting a connection which has a prepared XA transaction, when xa_detach_on_prepare is OFF. Signature matches that required by plugin_foreach.

◆ find_trn_for_recover_and_check_its_state()

std::shared_ptr< Transaction_ctx > find_trn_for_recover_and_check_its_state	(	THD *	thd,
		xid_t *	xid_for_trn_in_recover,
		XID_STATE *	xid_state
	)

Find XA transaction in cache by its xid value.

Parameters

thd	Thread context
xid_for_trn_in_recover	xid value to look for in transaction cache
xid_state	State of XA transaction in current session

Returns: Pointer to an instance of Transaction_ctx corresponding to a xid in argument. If XA transaction not found returns nullptr and sets an error in DA to specify a reason of search failure.

◆ ha_recover()

int ha_recover	(	Xid_commit_list *	commit_list = `nullptr`,
		Xa_state_list *	xa_state_list = `nullptr`
	)

Stage of the recovery process where information is collected from the storage engines (SE), merged with information from the transaction coordinator (TC) and transactions states are determined and enforced.

Implemented heuristics is as follows:

The commit_list parameter contains the set of internally coordinated transactions that the TC ensures were marked as committed.
The xa_state_list parameter contains the list of externally coordinated transactions and their states, as recorded by the TC.
For each SE: a. Collect list of transactions found in PREPARED_IN_TC state in the SE and merge it with the information collected from the TC, in xa_state_list. b. Retrieve the list of transactions found in prepared state in the SE.

c. For each internally coordinated transactions found in prepared state:
1. If the transaction is found in commit_list, commit it.
2. If the transaction is NOT found in commit_list but tc_heuristic_recover = TC_HEURISTIC_RECOVER_COMMIT, commit it.
3. Otherwise, roll it back.
d. For each externally coordinated transactions found in prepared state:
1. If the transaction isn't found in xa_state_list, roll it back.
2. If the transaction is found in xa_state_list in COMMITTED state, commit it.
3. If the transaction is found in xa_state_list in ROLLEDBACK state, roll it back.
4. If the transaction is found in xa_state_list in PREPARED state, ensure that the transaction state in the SE is PREPARED_IN_TC.

Parameters

commit_list	Set of XIDs of internally coordinated transactions found as been committed in the transaction coordinator state.
xa_state_list	Map between XIDs and states of externally coordinated transactions as found in the internal transaction coordinator state.

Returns: 0 if recovery was successful, non-zero otherwise.

◆ is_xa_prepare()

bool is_xa_prepare ( THD * thd )

Checks whether or not the underlying statement is an XA PREPARE.

Parameters

thd	THD session object.

Returns: true if the underlying statement is an XA PREPARE, false if not

◆ is_xa_rollback()

bool is_xa_rollback ( THD * thd )

Checks whether or not the underlying statement is an XA ROLLBACK.

Parameters

thd	THD session object.

Returns: true if the underlying statement is an XA ROLLBACK, false if not

◆ operator<<()

std::ostream & operator<<	(	std::ostream &	out,
		struct xid_t const &	in
	)

Parameters

out	The stream to write the XID representation to
in	The XID for which the string representation should be written

Returns: The reference for the stream passed on as parameter.

◆ reattach_native_trx()

bool reattach_native_trx	(	THD *	thd,
		plugin_ref	plugin,
		void *
	)

The function reattaches existing storage engines transaction context to thd.

Backup area to save it is provided to low level storage engine function.

is invoked by plugin_foreach() after trans_xa_prepare() for each storage engine.

Parameters

[in,out]	thd	Thread context
	plugin	Reference to handlerton

Returns: false on success, true otherwise.

◆ thd_holds_xa_transaction()

bool thd_holds_xa_transaction ( THD * thd )

Test if the THD session underlying transaction is an externally coordinated (XA) transaction.

Parameters

thd	The session THD object holding the transaction to be tested.

Returns: true if the session underlying transaction is an XA transaction, false otherwise.

◆ xa_trans_force_rollback()

bool xa_trans_force_rollback ( THD * thd )

Rollback the active XA transaction.

Note: Resets rm_error before calling ha_rollback(), so the thd->transaction.xid structure gets reset by ha_rollback() / THD::transaction::cleanup().

Returns: true if the rollback failed, false otherwise.

◆ xarecover_create_mdl_backup()

static bool xarecover_create_mdl_backup	(	XA_recover_txn &	txn,
		MEM_ROOT *	mem_root
	)

static

Variable Documentation

◆ MAX_XID_LIST_SIZE

const int MAX_XID_LIST_SIZE = 1024 * 128

static

◆ MIN_XID_LIST_SIZE

const int MIN_XID_LIST_SIZE = 128

static

◆ MYSQL_XID_GTRID_LEN

const uint MYSQL_XID_GTRID_LEN = MYSQL_XID_OFFSET + sizeof(my_xid)

static

◆ MYSQL_XID_OFFSET

const uint MYSQL_XID_OFFSET = MYSQL_XID_PREFIX_LEN + sizeof(server_id)

static

◆ MYSQL_XID_PREFIX_LEN

const uint MYSQL_XID_PREFIX_LEN = 8

static

Functions

Variables

Function Documentation

◆ acquire_mandatory_metadata_locks()

◆ applier_reset_xa_trans()

◆ attach_native_trx()

◆ cleanup_trans_state()

◆ detach_native_trx()

◆ disconnect_native_trx()

◆ find_trn_for_recover_and_check_its_state()

◆ ha_recover()

◆ is_xa_prepare()

◆ is_xa_rollback()

◆ operator<<()

◆ reattach_native_trx()

◆ thd_holds_xa_transaction()

◆ xa_trans_force_rollback()

◆ xarecover_create_mdl_backup()

Variable Documentation

◆ MAX_XID_LIST_SIZE

◆ MIN_XID_LIST_SIZE

◆ MYSQL_XID_GTRID_LEN

◆ MYSQL_XID_OFFSET

◆ MYSQL_XID_PREFIX_LEN