xa.cc File Reference

#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/psi_bits.h"
#include "mysql/components/services/log_builtins.h"
#include "mysql/components/services/mysql_mutex_bits.h"
#include "mysql/components/services/psi_mutex_bits.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_replica_commit_order_manager.h"
#include "sql/sql_class.h"
#include "sql/sql_const.h"
#include "sql/sql_error.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_string.h"
#include "template_utils.h"
#include "thr_mutex.h"

Classes
struct	transaction_free_hash
struct	xarecover_st

Functions
static std::string	to_string (const XID &xid)
static void	attach_native_trx (THD *thd)
	The function restores previously saved storage engine transaction context. More...
static bool	transaction_cache_insert (XID *xid, Transaction_ctx *transaction)
	Insert information about XA transaction into a cache indexed by XID. More...
static bool	transaction_cache_insert_recovery (XID *xid)
	Insert information about XA transaction being recovered into a cache indexed by XID. More...
static bool	xacommit_handlerton (THD *, plugin_ref plugin, void *arg)
static bool	xarollback_handlerton (THD *, plugin_ref plugin, void *arg)
static bool	ha_commit_or_rollback_by_xid (THD *, XID *xid, bool commit)
static bool	xarecover_create_mdl_backup (XA_recover_txn &txn, MEM_ROOT *mem_root)
static bool	xarecover_handlerton (THD *, plugin_ref plugin, void *arg)
int	ha_recover (const mem_root_unordered_set< my_xid > *commit_list)
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...
static 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...
static bool	acquire_mandatory_metadata_locks (THD *thd, xid_t *external_xid)
	Acquire Commit metadata lock and all locks acquired by a prepared XA transaction before server was shutdown or terminated. More...
static void	init_transaction_cache_psi_keys (void)
bool	transaction_cache_init ()
	Initialize a cache to store Transaction_ctx and a mutex to protect access to the cache. More...
void	transaction_cache_free ()
	Release resources occupied by transaction cache. More...
bool	create_and_insert_new_transaction (XID *xid, bool is_binlogged_arg)
bool	transaction_cache_detach (Transaction_ctx *transaction)
	Transaction is marked in the cache as if it's recovered. More...
void	transaction_cache_delete (Transaction_ctx *transaction)
	Remove information about transaction from a cache. 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...

Variables
static const int	MIN_XID_LIST_SIZE = 128
static const int	MAX_XID_LIST_SIZE = 1024 * 128
static bool	inited = false
static mysql_mutex_t	LOCK_transaction_cache
static malloc_unordered_map< std::string, std::shared_ptr< Transaction_ctx > >	transaction_cache {key_memory_xa_transaction_contexts}
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)
static PSI_mutex_key	key_LOCK_transaction_cache
static PSI_mutex_info	transaction_cache_mutexes []

Function Documentation

acquire_mandatory_metadata_locks()

static bool acquire_mandatory_metadata_locks ( THD *  thd, xid_t *  external_xid  )

static

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

Parameters

thd	Thread context
external_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

create_and_insert_new_transaction()

bool create_and_insert_new_transaction ( XID *  xid, bool  is_binlogged_arg  )

inline

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.

find_trn_for_recover_and_check_its_state()

static 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  )

static

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_commit_or_rollback_by_xid()

static bool ha_commit_or_rollback_by_xid ( THD *  , XID *  xid, bool  commit  )

static

ha_recover()

int ha_recover

(

const mem_root_unordered_set< my_xid > *

commit_list

)

init_transaction_cache_psi_keys()

static void init_transaction_cache_psi_keys ( void  )

static

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.

to_string()

static std::string to_string ( const XID &  xid )

static

transaction_cache_delete()

void transaction_cache_delete

(

Transaction_ctx *

transaction

)

Remove information about transaction from a cache.

Parameters

transaction

Pointer to a Transaction_ctx that has to be removed from a cache.

transaction_cache_detach()

bool transaction_cache_detach

(

Transaction_ctx *

transaction

)

Transaction is marked in the cache as if it's recovered.

The method allows to sustain prepared transaction disconnection.

Parameters

transaction

Pointer to Transaction object that is replaced.

Returns

operation result

Return values

false	success or a cache already contains XID_STATE for this XID value
true	failure

transaction_cache_free()

void transaction_cache_free

(

)

Release resources occupied by transaction cache.

transaction_cache_init()

bool transaction_cache_init

(

)

Initialize a cache to store Transaction_ctx and a mutex to protect access to the cache.

Returns

result of initialization

Return values

false	success
true	failure

transaction_cache_insert()

bool transaction_cache_insert ( XID *  xid, Transaction_ctx *  transaction  )

static

Insert information about XA transaction into a cache indexed by XID.

Parameters

xid	Pointer to a XID structure that identifies a XA transaction.
transaction	Pointer to Transaction object that is inserted.

Returns

operation result

Return values

false	success or a cache already contains XID_STATE for this XID value
true	failure

transaction_cache_insert_recovery()

bool transaction_cache_insert_recovery ( XID *  xid )

static

Insert information about XA transaction being recovered into a cache indexed by XID.

Parameters

xid	Pointer to a XID structure that identifies a XA transaction.

Returns

operation result

Return values

false	success or a cache already contains Transaction_ctx for this XID value
true	failure

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.

xacommit_handlerton()

static bool xacommit_handlerton ( THD *  , plugin_ref  plugin, void *  arg  )

static

xarecover_create_mdl_backup()

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

static

xarecover_handlerton()

static bool xarecover_handlerton ( THD *  , plugin_ref  plugin, void *  arg  )

static

xarollback_handlerton()

static bool xarollback_handlerton ( THD *  , plugin_ref  plugin, void *  arg  )

static

Variable Documentation

inited

bool inited = false

static

key_LOCK_transaction_cache

PSI_mutex_key key_LOCK_transaction_cache

static

LOCK_transaction_cache

mysql_mutex_t LOCK_transaction_cache

static

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

transaction_cache

malloc_unordered_map<std::string, std::shared_ptr<Transaction_ctx> > transaction_cache {key_memory_xa_transaction_contexts}

static

transaction_cache_mutexes

PSI_mutex_info transaction_cache_mutexes[]

static

Initial value:

= {
    {&key_LOCK_transaction_cache, "LOCK_transaction_cache", PSI_FLAG_SINGLETON,
     0, PSI_DOCUMENT_ME}}