/***************************************************************************** Copyright (c) 1996, 2013, Oracle and/or its affiliates. All Rights Reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA *****************************************************************************/ /**************************************************//** @file include/trx0trx.h The transaction Created 3/26/1996 Heikki Tuuri *******************************************************/ #ifndef trx0trx_h #define trx0trx_h #include "univ.i" #include "trx0types.h" #include "dict0types.h" #ifndef UNIV_HOTBACKUP #include "lock0types.h" #include "log0log.h" #include "usr0types.h" #include "que0types.h" #include "mem0mem.h" #include "read0types.h" #include "trx0xa.h" #include "ut0vec.h" #include "fts0fts.h" /** Dummy session used currently in MySQL interface */ extern sess_t* trx_dummy_sess; /********************************************************************//** Releases the search latch if trx has reserved it. */ UNIV_INLINE void trx_search_latch_release_if_reserved( /*=================================*/ trx_t* trx); /*!< in: transaction */ /******************************************************************//** Set detailed error message for the transaction. */ UNIV_INTERN void trx_set_detailed_error( /*===================*/ trx_t* trx, /*!< in: transaction struct */ const char* msg); /*!< in: detailed error message */ /*************************************************************//** Set detailed error message for the transaction from a file. Note that the file is rewinded before reading from it. */ UNIV_INTERN void trx_set_detailed_error_from_file( /*=============================*/ trx_t* trx, /*!< in: transaction struct */ FILE* file); /*!< in: file to read message from */ /****************************************************************//** Retrieves the error_info field from a trx. @return the error info */ UNIV_INLINE const dict_index_t* trx_get_error_info( /*===============*/ const trx_t* trx); /*!< in: trx object */ /********************************************************************//** Creates a transaction object for MySQL. @return own: transaction object */ UNIV_INTERN trx_t* trx_allocate_for_mysql(void); /*========================*/ /********************************************************************//** Creates a transaction object for background operations by the master thread. @return own: transaction object */ UNIV_INTERN trx_t* trx_allocate_for_background(void); /*=============================*/ /********************************************************************//** Frees a transaction object of a background operation of the master thread. */ UNIV_INTERN void trx_free_for_background( /*====================*/ trx_t* trx); /*!< in, own: trx object */ /********************************************************************//** At shutdown, frees a transaction object that is in the PREPARED state. */ UNIV_INTERN void trx_free_prepared( /*==============*/ trx_t* trx) /*!< in, own: trx object */ UNIV_COLD __attribute__((nonnull)); /********************************************************************//** Frees a transaction object for MySQL. */ UNIV_INTERN void trx_free_for_mysql( /*===============*/ trx_t* trx); /*!< in, own: trx object */ /****************************************************************//** Creates trx objects for transactions and initializes the trx list of trx_sys at database start. Rollback segment and undo log lists must already exist when this function is called, because the lists of transactions to be rolled back or cleaned up are built based on the undo log lists. */ UNIV_INTERN void trx_lists_init_at_db_start(void); /*============================*/ #ifdef UNIV_DEBUG #define trx_start_if_not_started_xa(t) \ { \ (t)->start_line = __LINE__; \ (t)->start_file = __FILE__; \ trx_start_if_not_started_xa_low((t)); \ } #else #define trx_start_if_not_started_xa(t) \ trx_start_if_not_started_xa_low((t)) #endif /* UNIV_DEBUG */ /*************************************************************//** Starts the transaction if it is not yet started. */ UNIV_INTERN void trx_start_if_not_started_xa_low( /*============================*/ trx_t* trx); /*!< in: transaction */ /*************************************************************//** Starts the transaction if it is not yet started. */ UNIV_INTERN void trx_start_if_not_started_low( /*=========================*/ trx_t* trx); /*!< in: transaction */ #ifdef UNIV_DEBUG #define trx_start_if_not_started(t) \ { \ (t)->start_line = __LINE__; \ (t)->start_file = __FILE__; \ trx_start_if_not_started_low((t)); \ } #else #define trx_start_if_not_started(t) \ trx_start_if_not_started_low((t)) #endif /* UNIV_DEBUG */ /*************************************************************//** Starts the transaction for a DDL operation. */ UNIV_INTERN void trx_start_for_ddl_low( /*==================*/ trx_t* trx, /*!< in/out: transaction */ trx_dict_op_t op) /*!< in: dictionary operation type */ __attribute__((nonnull)); #ifdef UNIV_DEBUG #define trx_start_for_ddl(t, o) \ { \ ut_ad((t)->start_file == 0); \ (t)->start_line = __LINE__; \ (t)->start_file = __FILE__; \ trx_start_for_ddl_low((t), (o)); \ } #else #define trx_start_for_ddl(t, o) \ trx_start_for_ddl_low((t), (o)) #endif /* UNIV_DEBUG */ /****************************************************************//** Commits a transaction. */ UNIV_INTERN void trx_commit( /*=======*/ trx_t* trx) /*!< in/out: transaction */ __attribute__((nonnull)); /****************************************************************//** Commits a transaction and a mini-transaction. */ UNIV_INTERN void trx_commit_low( /*===========*/ trx_t* trx, /*!< in/out: transaction */ mtr_t* mtr) /*!< in/out: mini-transaction (will be committed), or NULL if trx made no modifications */ __attribute__((nonnull(1))); /****************************************************************//** Cleans up a transaction at database startup. The cleanup is needed if the transaction already got to the middle of a commit when the database crashed, and we cannot roll it back. */ UNIV_INTERN void trx_cleanup_at_db_startup( /*======================*/ trx_t* trx); /*!< in: transaction */ /**********************************************************************//** Does the transaction commit for MySQL. @return DB_SUCCESS or error number */ UNIV_INTERN dberr_t trx_commit_for_mysql( /*=================*/ trx_t* trx); /*!< in/out: transaction */ /**********************************************************************//** Does the transaction prepare for MySQL. */ UNIV_INTERN void trx_prepare_for_mysql( /*==================*/ trx_t* trx); /*!< in/out: trx handle */ /**********************************************************************//** This function is used to find number of prepared transactions and their transaction objects for a recovery. @return number of prepared transactions */ UNIV_INTERN int trx_recover_for_mysql( /*==================*/ XID* xid_list, /*!< in/out: prepared transactions */ ulint len); /*!< in: number of slots in xid_list */ /*******************************************************************//** This function is used to find one X/Open XA distributed transaction which is in the prepared state @return trx or NULL; on match, the trx->xid will be invalidated; note that the trx may have been committed, unless the caller is holding lock_sys->mutex */ UNIV_INTERN trx_t * trx_get_trx_by_xid( /*===============*/ const XID* xid); /*!< in: X/Open XA transaction identifier */ /**********************************************************************//** If required, flushes the log to disk if we called trx_commit_for_mysql() with trx->flush_log_later == TRUE. */ UNIV_INTERN void trx_commit_complete_for_mysql( /*==========================*/ trx_t* trx) /*!< in/out: transaction */ __attribute__((nonnull)); /**********************************************************************//** Marks the latest SQL statement ended. */ UNIV_INTERN void trx_mark_sql_stat_end( /*==================*/ trx_t* trx); /*!< in: trx handle */ /********************************************************************//** Assigns a read view for a consistent read query. All the consistent reads within the same transaction will get the same read view, which is created when this function is first called for a new started transaction. @return consistent read view */ UNIV_INTERN read_view_t* trx_assign_read_view( /*=================*/ trx_t* trx); /*!< in: active transaction */ /****************************************************************//** Prepares a transaction for commit/rollback. */ UNIV_INTERN void trx_commit_or_rollback_prepare( /*===========================*/ trx_t* trx); /*!< in/out: transaction */ /*********************************************************************//** Creates a commit command node struct. @return own: commit node struct */ UNIV_INTERN commit_node_t* trx_commit_node_create( /*===================*/ mem_heap_t* heap); /*!< in: mem heap where created */ /***********************************************************//** Performs an execution step for a commit type node in a query graph. @return query thread to run next, or NULL */ UNIV_INTERN que_thr_t* trx_commit_step( /*============*/ que_thr_t* thr); /*!< in: query thread */ /**********************************************************************//** Prints info about a transaction. Caller must hold trx_sys->mutex. */ UNIV_INTERN void trx_print_low( /*==========*/ FILE* f, /*!< in: output stream */ const trx_t* trx, /*!< in: transaction */ ulint max_query_len, /*!< in: max query length to print, or 0 to use the default max length */ ulint n_rec_locks, /*!< in: lock_number_of_rows_locked(&trx->lock) */ ulint n_trx_locks, /*!< in: length of trx->lock.trx_locks */ ulint heap_size) /*!< in: mem_heap_get_size(trx->lock.lock_heap) */ __attribute__((nonnull)); /**********************************************************************//** Prints info about a transaction. The caller must hold lock_sys->mutex and trx_sys->mutex. When possible, use trx_print() instead. */ UNIV_INTERN void trx_print_latched( /*==============*/ FILE* f, /*!< in: output stream */ const trx_t* trx, /*!< in: transaction */ ulint max_query_len) /*!< in: max query length to print, or 0 to use the default max length */ __attribute__((nonnull)); /**********************************************************************//** Prints info about a transaction. Acquires and releases lock_sys->mutex and trx_sys->mutex. */ UNIV_INTERN void trx_print( /*======*/ FILE* f, /*!< in: output stream */ const trx_t* trx, /*!< in: transaction */ ulint max_query_len) /*!< in: max query length to print, or 0 to use the default max length */ __attribute__((nonnull)); /**********************************************************************//** Determine if a transaction is a dictionary operation. @return dictionary operation mode */ UNIV_INLINE enum trx_dict_op_t trx_get_dict_operation( /*===================*/ const trx_t* trx) /*!< in: transaction */ __attribute__((pure)); /**********************************************************************//** Flag a transaction a dictionary operation. */ UNIV_INLINE void trx_set_dict_operation( /*===================*/ trx_t* trx, /*!< in/out: transaction */ enum trx_dict_op_t op); /*!< in: operation, not TRX_DICT_OP_NONE */ #ifndef UNIV_HOTBACKUP /**********************************************************************//** Determines if a transaction is in the given state. The caller must hold trx_sys->mutex, or it must be the thread that is serving a running transaction. A running transaction must be in trx_sys->ro_trx_list or trx_sys->rw_trx_list unless it is a non-locking autocommit read only transaction, which is only in trx_sys->mysql_trx_list. @return TRUE if trx->state == state */ UNIV_INLINE ibool trx_state_eq( /*=========*/ const trx_t* trx, /*!< in: transaction */ trx_state_t state) /*!< in: state; if state != TRX_STATE_NOT_STARTED asserts that trx->state != TRX_STATE_NOT_STARTED */ __attribute__((nonnull, warn_unused_result)); # ifdef UNIV_DEBUG /**********************************************************************//** Asserts that a transaction has been started. The caller must hold trx_sys->mutex. @return TRUE if started */ UNIV_INTERN ibool trx_assert_started( /*===============*/ const trx_t* trx) /*!< in: transaction */ __attribute__((nonnull, warn_unused_result)); # endif /* UNIV_DEBUG */ /**********************************************************************//** Determines if the currently running transaction has been interrupted. @return TRUE if interrupted */ UNIV_INTERN ibool trx_is_interrupted( /*===============*/ const trx_t* trx); /*!< in: transaction */ /**********************************************************************//** Determines if the currently running transaction is in strict mode. @return TRUE if strict */ UNIV_INTERN ibool trx_is_strict( /*==========*/ trx_t* trx); /*!< in: transaction */ #else /* !UNIV_HOTBACKUP */ #define trx_is_interrupted(trx) FALSE #endif /* !UNIV_HOTBACKUP */ /*******************************************************************//** Calculates the "weight" of a transaction. The weight of one transaction is estimated as the number of altered rows + the number of locked rows. @param t transaction @return transaction weight */ #define TRX_WEIGHT(t) ((t)->undo_no + UT_LIST_GET_LEN((t)->lock.trx_locks)) /*******************************************************************//** Compares the "weight" (or size) of two transactions. Transactions that have edited non-transactional tables are considered heavier than ones that have not. @return TRUE if weight(a) >= weight(b) */ UNIV_INTERN ibool trx_weight_ge( /*==========*/ const trx_t* a, /*!< in: the first transaction to be compared */ const trx_t* b); /*!< in: the second transaction to be compared */ /* Maximum length of a string that can be returned by trx_get_que_state_str(). */ #define TRX_QUE_STATE_STR_MAX_LEN 12 /* "ROLLING BACK" */ /*******************************************************************//** Retrieves transaction's que state in a human readable string. The string should not be free()'d or modified. @return string in the data segment */ UNIV_INLINE const char* trx_get_que_state_str( /*==================*/ const trx_t* trx); /*!< in: transaction */ /****************************************************************//** Assign a read-only transaction a rollback-segment, if it is attempting to write to a TEMPORARY table. */ UNIV_INTERN void trx_assign_rseg( /*============*/ trx_t* trx); /*!< A read-only transaction that needs to be assigned a RBS. */ /*******************************************************************//** Transactions that aren't started by the MySQL server don't set the trx_t::mysql_thd field. For such transactions we set the lock wait timeout to 0 instead of the user configured value that comes from innodb_lock_wait_timeout via trx_t::mysql_thd. @param trx transaction @return lock wait timeout in seconds */ #define trx_lock_wait_timeout_get(trx) \ ((trx)->mysql_thd != NULL \ ? thd_lock_wait_timeout((trx)->mysql_thd) \ : 0) /*******************************************************************//** Determine if the transaction is a non-locking autocommit select (implied read-only). @param t transaction @return true if non-locking autocommit select transaction. */ #define trx_is_autocommit_non_locking(t) \ ((t)->auto_commit && (t)->will_lock == 0) /*******************************************************************//** Determine if the transaction is a non-locking autocommit select with an explicit check for the read-only status. @param t transaction @return true if non-locking autocommit read-only transaction. */ #define trx_is_ac_nl_ro(t) \ ((t)->read_only && trx_is_autocommit_non_locking((t))) /*******************************************************************//** Assert that the transaction is in the trx_sys_t::rw_trx_list */ #define assert_trx_in_rw_list(t) do { \ ut_ad(!(t)->read_only); \ assert_trx_in_list(t); \ } while (0) /*******************************************************************//** Assert that the transaction is either in trx_sys->ro_trx_list or trx_sys->rw_trx_list but not both and it cannot be an autocommit non-locking select */ #define assert_trx_in_list(t) do { \ ut_ad((t)->in_ro_trx_list == (t)->read_only); \ ut_ad((t)->in_rw_trx_list == !(t)->read_only); \ ut_ad(!trx_is_autocommit_non_locking((t))); \ switch ((t)->state) { \ case TRX_STATE_PREPARED: \ /* fall through */ \ case TRX_STATE_ACTIVE: \ case TRX_STATE_COMMITTED_IN_MEMORY: \ continue; \ case TRX_STATE_NOT_STARTED: \ break; \ } \ ut_error; \ } while (0) #ifdef UNIV_DEBUG /*******************************************************************//** Assert that an autocommit non-locking select cannot be in the ro_trx_list nor the rw_trx_list and that it is a read-only transaction. The tranasction must be in the mysql_trx_list. */ # define assert_trx_nonlocking_or_in_list(t) \ do { \ if (trx_is_autocommit_non_locking(t)) { \ trx_state_t t_state = (t)->state; \ ut_ad((t)->read_only); \ ut_ad(!(t)->is_recovered); \ ut_ad(!(t)->in_ro_trx_list); \ ut_ad(!(t)->in_rw_trx_list); \ ut_ad((t)->in_mysql_trx_list); \ ut_ad(t_state == TRX_STATE_NOT_STARTED \ || t_state == TRX_STATE_ACTIVE); \ } else { \ assert_trx_in_list(t); \ } \ } while (0) #else /* UNIV_DEBUG */ /*******************************************************************//** Assert that an autocommit non-locking slect cannot be in the ro_trx_list nor the rw_trx_list and that it is a read-only transaction. The tranasction must be in the mysql_trx_list. */ # define assert_trx_nonlocking_or_in_list(trx) ((void)0) #endif /* UNIV_DEBUG */ /*******************************************************************//** Latching protocol for trx_lock_t::que_state. trx_lock_t::que_state captures the state of the query thread during the execution of a query. This is different from a transaction state. The query state of a transaction can be updated asynchronously by other threads. The other threads can be system threads, like the timeout monitor thread or user threads executing other queries. Another thing to be mindful of is that there is a delay between when a query thread is put into LOCK_WAIT state and before it actually starts waiting. Between these two events it is possible that the query thread is granted the lock it was waiting for, which implies that the state can be changed asynchronously. All these operations take place within the context of locking. Therefore state changes within the locking code must acquire both the lock mutex and the trx->mutex when changing trx->lock.que_state to TRX_QUE_LOCK_WAIT or trx->lock.wait_lock to non-NULL but when the lock wait ends it is sufficient to only acquire the trx->mutex. To query the state either of the mutexes is sufficient within the locking code and no mutex is required when the query thread is no longer waiting. */ /** The locks and state of an active transaction. Protected by lock_sys->mutex, trx->mutex or both. */ struct trx_lock_t { ulint n_active_thrs; /*!< number of active query threads */ trx_que_t que_state; /*!< valid when trx->state == TRX_STATE_ACTIVE: TRX_QUE_RUNNING, TRX_QUE_LOCK_WAIT, ... */ lock_t* wait_lock; /*!< if trx execution state is TRX_QUE_LOCK_WAIT, this points to the lock request, otherwise this is NULL; set to non-NULL when holding both trx->mutex and lock_sys->mutex; set to NULL when holding lock_sys->mutex; readers should hold lock_sys->mutex, except when they are holding trx->mutex and wait_lock==NULL */ ib_uint64_t deadlock_mark; /*!< A mark field that is initialized to and checked against lock_mark_counter by lock_deadlock_recursive(). */ ibool was_chosen_as_deadlock_victim; /*!< when the transaction decides to wait for a lock, it sets this to FALSE; if another transaction chooses this transaction as a victim in deadlock resolution, it sets this to TRUE. Protected by trx->mutex. */ time_t wait_started; /*!< lock wait started at this time, protected only by lock_sys->mutex */ que_thr_t* wait_thr; /*!< query thread belonging to this trx that is in QUE_THR_LOCK_WAIT state. For threads suspended in a lock wait, this is protected by lock_sys->mutex. Otherwise, this may only be modified by the thread that is serving the running transaction. */ mem_heap_t* lock_heap; /*!< memory heap for trx_locks; protected by lock_sys->mutex */ UT_LIST_BASE_NODE_T(lock_t) trx_locks; /*!< locks requested by the transaction; insertions are protected by trx->mutex and lock_sys->mutex; removals are protected by lock_sys->mutex */ ib_vector_t* table_locks; /*!< All table locks requested by this transaction, including AUTOINC locks */ ibool cancel; /*!< TRUE if the transaction is being rolled back either via deadlock detection or due to lock timeout. The caller has to acquire the trx_t::mutex in order to cancel the locks. In lock_trx_table_locks_remove() we check for this cancel of a transaction's locks and avoid reacquiring the trx mutex to prevent recursive deadlocks. Protected by both the lock sys mutex and the trx_t::mutex. */ }; #define TRX_MAGIC_N 91118598 /** The transaction handle Normally, there is a 1:1 relationship between a transaction handle (trx) and a session (client connection). One session is associated with exactly one user transaction. There are some exceptions to this: * For DDL operations, a subtransaction is allocated that modifies the data dictionary tables. Lock waits and deadlocks are prevented by acquiring the dict_operation_lock before starting the subtransaction and releasing it after committing the subtransaction. * The purge system uses a special transaction that is not associated with any session. * If the system crashed or it was quickly shut down while there were transactions in the ACTIVE or PREPARED state, these transactions would no longer be associated with a session when the server is restarted. A session may be served by at most one thread at a time. The serving thread of a session might change in some MySQL implementations. Therefore we do not have os_thread_get_curr_id() assertions in the code. Normally, only the thread that is currently associated with a running transaction may access (read and modify) the trx object, and it may do so without holding any mutex. The following are exceptions to this: * trx_rollback_resurrected() may access resurrected (connectionless) transactions while the system is already processing new user transactions. The trx_sys->mutex prevents a race condition between it and lock_trx_release_locks() [invoked by trx_commit()]. * trx_print_low() may access transactions not associated with the current thread. The caller must be holding trx_sys->mutex and lock_sys->mutex. * When a transaction handle is in the trx_sys->mysql_trx_list or trx_sys->trx_list, some of its fields must not be modified without holding trx_sys->mutex exclusively. * The locking code (in particular, lock_deadlock_recursive() and lock_rec_convert_impl_to_expl()) will access transactions associated to other connections. The locks of transactions are protected by lock_sys->mutex and sometimes by trx->mutex. */ typedef enum { TRX_SERVER_ABORT = 0, TRX_WSREP_ABORT = 1, TRX_REPLICATION_ABORT = 2 } trx_abort_t; struct trx_t{ ulint magic_n; ib_mutex_t mutex; /*!< Mutex protecting the fields state and lock (except some fields of lock, which are protected by lock_sys->mutex) */ /** State of the trx from the point of view of concurrency control and the valid state transitions. Possible states: TRX_STATE_NOT_STARTED TRX_STATE_ACTIVE TRX_STATE_PREPARED TRX_STATE_COMMITTED_IN_MEMORY (alias below COMMITTED) Valid state transitions are: Regular transactions: * NOT_STARTED -> ACTIVE -> COMMITTED -> NOT_STARTED Auto-commit non-locking read-only: * NOT_STARTED -> ACTIVE -> NOT_STARTED XA (2PC): * NOT_STARTED -> ACTIVE -> PREPARED -> COMMITTED -> NOT_STARTED Recovered XA: * NOT_STARTED -> PREPARED -> COMMITTED -> (freed) XA (2PC) (shutdown before ROLLBACK or COMMIT): * NOT_STARTED -> PREPARED -> (freed) Latching and various transaction lists membership rules: XA (2PC) transactions are always treated as non-autocommit. Transitions to ACTIVE or NOT_STARTED occur when !in_rw_trx_list and !in_ro_trx_list (no trx_sys->mutex needed). Autocommit non-locking read-only transactions move between states without holding any mutex. They are !in_rw_trx_list, !in_ro_trx_list. When a transaction is NOT_STARTED, it can be in_mysql_trx_list if it is a user transaction. It cannot be in ro_trx_list or rw_trx_list. ACTIVE->PREPARED->COMMITTED is only possible when trx->in_rw_trx_list. The transition ACTIVE->PREPARED is protected by trx_sys->mutex. ACTIVE->COMMITTED is possible when the transaction is in ro_trx_list or rw_trx_list. Transitions to COMMITTED are protected by both lock_sys->mutex and trx->mutex. NOTE: Some of these state change constraints are an overkill, currently only required for a consistent view for printing stats. This unnecessarily adds a huge cost for the general case. NOTE: In the future we should add read only transactions to the ro_trx_list the first time they try to acquire a lock ie. by default we treat all read-only transactions as non-locking. */ trx_state_t state; trx_lock_t lock; /*!< Information about the transaction locks and state. Protected by trx->mutex or lock_sys->mutex or both */ ulint is_recovered; /*!< 0=normal transaction, 1=recovered, must be rolled back, protected by trx_sys->mutex when trx->in_rw_trx_list holds */ /* These fields are not protected by any mutex. */ const char* op_info; /*!< English text describing the current operation, or an empty string */ ulint isolation_level;/*!< TRX_ISO_REPEATABLE_READ, ... */ ulint check_foreigns; /*!< normally TRUE, but if the user wants to suppress foreign key checks, (in table imports, for example) we set this FALSE */ /*------------------------------*/ /* MySQL has a transaction coordinator to coordinate two phase commit between multiple storage engines and the binary log. When an engine participates in a transaction, it's responsible for registering itself using the trans_register_ha() API. */ unsigned is_registered:1;/* This flag is set to 1 after the transaction has been registered with the coordinator using the XA API, and is set to 0 after commit or rollback. */ unsigned active_commit_ordered:1;/* 1 if owns prepare mutex, if this is set to 1 then registered should also be set to 1. This is used in the XA code */ /*------------------------------*/ ulint check_unique_secondary; /*!< normally TRUE, but if the user wants to speed up inserts by suppressing unique key checks for secondary indexes when we decide if we can use the insert buffer for them, we set this FALSE */ ulint support_xa; /*!< normally we do the XA two-phase commit steps, but by setting this to FALSE, one can save CPU time and about 150 bytes in the undo log size as then we skip XA steps */ ulint flush_log_later;/* In 2PC, we hold the prepare_commit mutex across both phases. In that case, we defer flush of the logs to disk until after we release the mutex. */ ulint must_flush_log_later;/*!< this flag is set to TRUE in trx_commit() if flush_log_later was TRUE, and there were modifications by the transaction; in that case we must flush the log in trx_commit_complete_for_mysql() */ ulint duplicates; /*!< TRX_DUP_IGNORE | TRX_DUP_REPLACE */ ulint has_search_latch; /*!< TRUE if this trx has latched the search system latch in S-mode */ ulint search_latch_timeout; /*!< If we notice that someone is waiting for our S-lock on the search latch to be released, we wait in row0sel.cc for BTR_SEA_TIMEOUT new searches until we try to keep the search latch again over calls from MySQL; this is intended to reduce contention on the search latch */ trx_dict_op_t dict_operation; /**< @see enum trx_dict_op */ /* Fields protected by the srv_conc_mutex. */ ulint declared_to_be_inside_innodb; /*!< this is TRUE if we have declared this transaction in srv_conc_enter_innodb to be inside the InnoDB engine */ ulint n_tickets_to_enter_innodb; /*!< this can be > 0 only when declared_to_... is TRUE; when we come to srv_conc_innodb_enter, if the value here is > 0, we decrement this by 1 */ ulint dict_operation_lock_mode; /*!< 0, RW_S_LATCH, or RW_X_LATCH: the latch mode trx currently holds on dict_operation_lock. Protected by dict_operation_lock. */ trx_id_t no; /*!< transaction serialization number: max trx id shortly before the transaction is moved to COMMITTED_IN_MEMORY state. Protected by trx_sys_t::mutex when trx->in_rw_trx_list. Initially set to TRX_ID_MAX. */ time_t start_time; /*!< time the trx state last time became TRX_STATE_ACTIVE */ trx_id_t id; /*!< transaction id */ XID xid; /*!< X/Open XA transaction identification to identify a transaction branch */ lsn_t commit_lsn; /*!< lsn at the time of the commit */ table_id_t table_id; /*!< Table to drop iff dict_operation == TRX_DICT_OP_TABLE, or 0. */ /*------------------------------*/ THD* mysql_thd; /*!< MySQL thread handle corresponding to this trx, or NULL */ trx_abort_t abort_type; /*!< Transaction abort type*/ const char* mysql_log_file_name; /*!< if MySQL binlog is used, this field contains a pointer to the latest file name; this is NULL if binlog is not used */ ib_int64_t mysql_log_offset; /*!< if MySQL binlog is used, this field contains the end offset of the binlog entry */ /*------------------------------*/ ulint n_mysql_tables_in_use; /*!< number of Innobase tables used in the processing of the current SQL statement in MySQL */ ulint mysql_n_tables_locked; /*!< how many tables the current SQL statement uses, except those in consistent read */ /*------------------------------*/ UT_LIST_NODE_T(trx_t) trx_list; /*!< list of transactions; protected by trx_sys->mutex. The same node is used for both trx_sys_t::ro_trx_list and trx_sys_t::rw_trx_list */ #ifdef UNIV_DEBUG /** The following two fields are mutually exclusive. */ /* @{ */ ibool in_ro_trx_list; /*!< TRUE if in trx_sys->ro_trx_list */ ibool in_rw_trx_list; /*!< TRUE if in trx_sys->rw_trx_list */ /* @} */ #endif /* UNIV_DEBUG */ UT_LIST_NODE_T(trx_t) mysql_trx_list; /*!< list of transactions created for MySQL; protected by trx_sys->mutex */ #ifdef UNIV_DEBUG ibool in_mysql_trx_list; /*!< TRUE if in trx_sys->mysql_trx_list */ #endif /* UNIV_DEBUG */ /*------------------------------*/ dberr_t error_state; /*!< 0 if no error, otherwise error number; NOTE That ONLY the thread doing the transaction is allowed to set this field: this is NOT protected by any mutex */ const dict_index_t*error_info; /*!< if the error number indicates a duplicate key error, a pointer to the problematic index is stored here */ ulint error_key_num; /*!< if the index creation fails to a duplicate key error, a mysql key number of that index is stored here */ sess_t* sess; /*!< session of the trx, NULL if none */ que_t* graph; /*!< query currently run in the session, or NULL if none; NOTE that the query belongs to the session, and it can survive over a transaction commit, if it is a stored procedure with a COMMIT WORK statement, for instance */ mem_heap_t* global_read_view_heap; /*!< memory heap for the global read view */ read_view_t* global_read_view; /*!< consistent read view associated to a transaction or NULL */ read_view_t* read_view; /*!< consistent read view used in the transaction or NULL, this read view if defined can be normal read view associated to a transaction (i.e. same as global_read_view) or read view associated to a cursor */ /*------------------------------*/ UT_LIST_BASE_NODE_T(trx_named_savept_t) trx_savepoints; /*!< savepoints set with SAVEPOINT ..., oldest first */ /*------------------------------*/ ib_mutex_t undo_mutex; /*!< mutex protecting the fields in this section (down to undo_no_arr), EXCEPT last_sql_stat_start, which can be accessed only when we know that there cannot be any activity in the undo logs! */ undo_no_t undo_no; /*!< next undo log record number to assign; since the undo log is private for a transaction, this is a simple ascending sequence with no gaps; thus it represents the number of modified/inserted rows in a transaction */ trx_savept_t last_sql_stat_start; /*!< undo_no when the last sql statement was started: in case of an error, trx is rolled back down to this undo number; see note at undo_mutex! */ trx_rseg_t* rseg; /*!< rollback segment assigned to the transaction, or NULL if not assigned yet */ trx_undo_t* insert_undo; /*!< pointer to the insert undo log, or NULL if no inserts performed yet */ trx_undo_t* update_undo; /*!< pointer to the update undo log, or NULL if no update performed yet */ undo_no_t roll_limit; /*!< least undo number to undo during a rollback */ ulint pages_undone; /*!< number of undo log pages undone since the last undo log truncation */ trx_undo_arr_t* undo_no_arr; /*!< array of undo numbers of undo log records which are currently processed by a rollback operation */ /*------------------------------*/ ulint n_autoinc_rows; /*!< no. of AUTO-INC rows required for an SQL statement. This is useful for multi-row INSERTs */ ib_vector_t* autoinc_locks; /* AUTOINC locks held by this transaction. Note that these are also in the lock list trx_locks. This vector needs to be freed explicitly when the trx instance is destroyed. Protected by lock_sys->mutex. */ /*------------------------------*/ ibool read_only; /*!< TRUE if transaction is flagged as a READ-ONLY transaction. if !auto_commit || will_lock > 0 then it will added to the list trx_sys_t::ro_trx_list. A read only transaction will not be assigned an UNDO log. Non-locking auto-commit read-only transaction will not be on either list. */ ibool auto_commit; /*!< TRUE if it is an autocommit */ ulint will_lock; /*!< Will acquire some locks. Increment each time we determine that a lock will be acquired by the MySQL layer. */ bool ddl; /*!< true if it is a transaction that is being started for a DDL operation */ /*------------------------------*/ fts_trx_t* fts_trx; /*!< FTS information, or NULL if transaction hasn't modified tables with FTS indexes (yet). */ doc_id_t fts_next_doc_id;/* The document id used for updates */ /*------------------------------*/ ulint flush_tables; /*!< if "covering" the FLUSH TABLES", count of tables being flushed. */ /*------------------------------*/ #ifdef UNIV_DEBUG ulint start_line; /*!< Track where it was started from */ const char* start_file; /*!< Filename where it was started */ #endif /* UNIV_DEBUG */ /*------------------------------*/ bool api_trx; /*!< trx started by InnoDB API */ bool api_auto_commit;/*!< automatic commit */ bool read_write; /*!< if read and write operation */ /*------------------------------*/ char detailed_error[256]; /*!< detailed error message for last error, or empty. */ /* Lock wait statistics */ ulint n_rec_lock_waits; /*!< Number of record lock waits, might not be exactly correct. */ ulint n_table_lock_waits; /*!< Number of table lock waits, might not be exactly correct. */ ulint total_rec_lock_wait_time; /*!< Total rec lock wait time up to this moment. */ ulint total_table_lock_wait_time; /*!< Total table lock wait time up to this moment. */ #ifdef WITH_WSREP os_event_t wsrep_event; /* event waited for in srv_conc_slot */ #endif /* WITH_WSREP */ }; /* Transaction isolation levels (trx->isolation_level) */ #define TRX_ISO_READ_UNCOMMITTED 0 /* dirty read: non-locking SELECTs are performed so that we do not look at a possible earlier version of a record; thus they are not 'consistent' reads under this isolation level; otherwise like level 2 */ #define TRX_ISO_READ_COMMITTED 1 /* somewhat Oracle-like isolation, except that in range UPDATE and DELETE we must block phantom rows with next-key locks; SELECT ... FOR UPDATE and ... LOCK IN SHARE MODE only lock the index records, NOT the gaps before them, and thus allow free inserting; each consistent read reads its own snapshot */ #define TRX_ISO_REPEATABLE_READ 2 /* this is the default; all consistent reads in the same trx read the same snapshot; full next-key locking used in locking reads to block insertions into gaps */ #define TRX_ISO_SERIALIZABLE 3 /* all plain SELECTs are converted to LOCK IN SHARE MODE reads */ /* Treatment of duplicate values (trx->duplicates; for example, in inserts). Multiple flags can be combined with bitwise OR. */ #define TRX_DUP_IGNORE 1 /* duplicate rows are to be updated */ #define TRX_DUP_REPLACE 2 /* duplicate rows are to be replaced */ /* Types of a trx signal */ #define TRX_SIG_NO_SIGNAL 0 #define TRX_SIG_TOTAL_ROLLBACK 1 #define TRX_SIG_ROLLBACK_TO_SAVEPT 2 #define TRX_SIG_COMMIT 3 #define TRX_SIG_BREAK_EXECUTION 5 /* Sender types of a signal */ #define TRX_SIG_SELF 0 /* sent by the session itself, or by an error occurring within this session */ #define TRX_SIG_OTHER_SESS 1 /* sent by another session (which must hold rights to this) */ /** Commit node states */ enum commit_node_state { COMMIT_NODE_SEND = 1, /*!< about to send a commit signal to the transaction */ COMMIT_NODE_WAIT /*!< commit signal sent to the transaction, waiting for completion */ }; /** Commit command node in a query graph */ struct commit_node_t{ que_common_t common; /*!< node type: QUE_NODE_COMMIT */ enum commit_node_state state; /*!< node execution state */ }; /** Test if trx->mutex is owned. */ #define trx_mutex_own(t) mutex_own(&t->mutex) /** Acquire the trx->mutex. */ #define trx_mutex_enter(t) do { \ mutex_enter(&t->mutex); \ } while (0) /** Release the trx->mutex. */ #define trx_mutex_exit(t) do { \ mutex_exit(&t->mutex); \ } while (0) /** @brief The latch protecting the adaptive search system This latch protects the (1) hash index; (2) columns of a record to which we have a pointer in the hash index; but does NOT protect: (3) next record offset field in a record; (4) next or previous records on the same page. Bear in mind (3) and (4) when using the hash index. */ extern rw_lock_t* btr_search_latch_temp; /** The latch protecting the adaptive search system */ #define btr_search_latch (*btr_search_latch_temp) #ifndef UNIV_NONINL #include "trx0trx.ic" #endif #endif /* !UNIV_HOTBACKUP */ #endif