/****************************************************** The transaction (c) 1996 Innobase Oy Created 3/26/1996 Heikki Tuuri *******************************************************/ #ifndef trx0trx_h #define trx0trx_h #include "univ.i" #include "trx0types.h" #include "lock0types.h" #include "usr0types.h" #include "que0types.h" #include "mem0mem.h" #include "read0types.h" #include "dict0types.h" #include "trx0xa.h" /* Number of transactions currently allocated for MySQL: protected by the kernel mutex */ extern ulint trx_n_mysql_transactions; /* Number of transactions currently in the XA PREPARED state: protected by the kernel mutex */ extern ulint trx_n_prepared; /************************************************************************ Releases the search latch if trx has reserved it. */ void trx_search_latch_release_if_reserved( /*=================================*/ trx_t* trx); /* in: transaction */ /********************************************************************** Set detailed error message for the transaction. */ 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. */ 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. */ void* trx_get_error_info( /*===============*/ /* out: the error info */ trx_t* trx); /* in: trx object */ /******************************************************************** Creates and initializes a transaction object. */ trx_t* trx_create( /*=======*/ /* out, own: the transaction */ sess_t* sess); /* in: session or NULL */ /************************************************************************ Creates a transaction object for MySQL. */ trx_t* trx_allocate_for_mysql(void); /*========================*/ /* out, own: transaction object */ /************************************************************************ Creates a transaction object for background operations by the master thread. */ trx_t* trx_allocate_for_background(void); /*=============================*/ /* out, own: transaction object */ /************************************************************************ Frees a transaction object. */ void trx_free( /*=====*/ trx_t* trx); /* in, own: trx object */ /************************************************************************ Frees a transaction object for MySQL. */ void trx_free_for_mysql( /*===============*/ trx_t* trx); /* in, own: trx object */ /************************************************************************ Frees a transaction object of a background operation of the master thread. */ void trx_free_for_background( /*====================*/ 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. */ void trx_lists_init_at_db_start(void); /*============================*/ /******************************************************************** Starts a new transaction. */ ibool trx_start( /*======*/ /* out: TRUE if success, FALSE if the rollback segment could not support this many transactions */ trx_t* trx, /* in: transaction */ ulint rseg_id);/* in: rollback segment id; if ULINT_UNDEFINED is passed, the system chooses the rollback segment automatically in a round-robin fashion */ /******************************************************************** Starts a new transaction. */ ibool trx_start_low( /*==========*/ /* out: TRUE */ trx_t* trx, /* in: transaction */ ulint rseg_id);/* in: rollback segment id; if ULINT_UNDEFINED is passed, the system chooses the rollback segment automatically in a round-robin fashion */ /***************************************************************** Starts the transaction if it is not yet started. */ UNIV_INLINE void trx_start_if_not_started( /*=====================*/ trx_t* trx); /* in: transaction */ /***************************************************************** Starts the transaction if it is not yet started. Assumes we have reserved the kernel mutex! */ UNIV_INLINE void trx_start_if_not_started_low( /*=========================*/ trx_t* trx); /* in: transaction */ /***************************************************************** Starts the transaction if it is not yet started. */ void trx_start_if_not_started_noninline( /*===============================*/ trx_t* trx); /* in: transaction */ /******************************************************************** Commits a transaction. */ void trx_commit_off_kernel( /*==================*/ trx_t* trx); /* in: transaction */ /******************************************************************** 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, andf we cannot roll it back. */ void trx_cleanup_at_db_startup( /*======================*/ trx_t* trx); /* in: transaction */ /************************************************************************** Does the transaction commit for MySQL. */ ulint trx_commit_for_mysql( /*=================*/ /* out: 0 or error number */ trx_t* trx); /* in: trx handle */ /************************************************************************** Does the transaction prepare for MySQL. */ ulint trx_prepare_for_mysql( /*==================*/ /* out: 0 or error number */ trx_t* trx); /* in: trx handle */ /************************************************************************** This function is used to find number of prepared transactions and their transaction objects for a recovery. */ int trx_recover_for_mysql( /*==================*/ /* out: number of prepared transactions */ 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 */ trx_t * trx_get_trx_by_xid( /*===============*/ /* out: trx or NULL; on match, the trx->xid will be invalidated */ 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. */ ulint trx_commit_complete_for_mysql( /*==========================*/ /* out: 0 or error number */ trx_t* trx); /* in: trx handle */ /************************************************************************** Marks the latest SQL statement ended. */ 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. */ read_view_t* trx_assign_read_view( /*=================*/ /* out: consistent read view */ trx_t* trx); /* in: active transaction */ /*************************************************************** The transaction must be in the TRX_QUE_LOCK_WAIT state. Puts it to the TRX_QUE_RUNNING state and releases query threads which were waiting for a lock in the wait_thrs list. */ void trx_end_lock_wait( /*==============*/ trx_t* trx); /* in: transaction */ /******************************************************************** Sends a signal to a trx object. */ void trx_sig_send( /*=========*/ trx_t* trx, /* in: trx handle */ ulint type, /* in: signal type */ ulint sender, /* in: TRX_SIG_SELF or TRX_SIG_OTHER_SESS */ que_thr_t* receiver_thr, /* in: query thread which wants the reply, or NULL; if type is TRX_SIG_END_WAIT, this must be NULL */ trx_savept_t* savept, /* in: possible rollback savepoint, or NULL */ que_thr_t** next_thr); /* in/out: next query thread to run; if the value which is passed in is a pointer to a NULL pointer, then the calling function can start running a new query thread; if the parameter is NULL, it is ignored */ /******************************************************************** Send the reply message when a signal in the queue of the trx has been handled. */ void trx_sig_reply( /*==========*/ trx_sig_t* sig, /* in: signal */ que_thr_t** next_thr); /* in/out: next query thread to run; if the value which is passed in is a pointer to a NULL pointer, then the calling function can start running a new query thread */ /******************************************************************** Removes the signal object from a trx signal queue. */ void trx_sig_remove( /*===========*/ trx_t* trx, /* in: trx handle */ trx_sig_t* sig); /* in, own: signal */ /******************************************************************** Starts handling of a trx signal. */ void trx_sig_start_handle( /*=================*/ trx_t* trx, /* in: trx handle */ que_thr_t** next_thr); /* in/out: next query thread to run; if the value which is passed in is a pointer to a NULL pointer, then the calling function can start running a new query thread */ /******************************************************************** Ends signal handling. If the session is in the error state, and trx->graph_before_signal_handling != NULL, returns control to the error handling routine of the graph (currently only returns the control to the graph root which then sends an error message to the client). */ void trx_end_signal_handling( /*====================*/ trx_t* trx); /* in: trx */ /************************************************************************* Creates a commit command node struct. */ commit_node_t* commit_node_create( /*===============*/ /* out, own: commit node struct */ mem_heap_t* heap); /* in: mem heap where created */ /*************************************************************** Performs an execution step for a commit type node in a query graph. */ que_thr_t* trx_commit_step( /*============*/ /* out: query thread to run next, or NULL */ que_thr_t* thr); /* in: query thread */ /************************************************************************** Prints info about a transaction to the given file. The caller must own the kernel mutex. */ void trx_print( /*======*/ FILE* f, /* in: output stream */ trx_t* trx, /* in: transaction */ ulint max_query_len); /* in: max query length to print, or 0 to use the default max length */ #ifndef UNIV_HOTBACKUP /************************************************************************** Determines if the currently running transaction has been interrupted. */ ibool trx_is_interrupted( /*===============*/ /* out: TRUE if interrupted */ trx_t* trx); /* in: transaction */ #else /* !UNIV_HOTBACKUP */ #define trx_is_interrupted(trx) FALSE #endif /* !UNIV_HOTBACKUP */ /*********************************************************************** Compares the "weight" (or size) of two transactions. The weight of one transaction is estimated as the number of altered rows + the number of locked rows. Transactions that have edited non-transactional tables are considered heavier than ones that have not. */ int trx_weight_cmp( /*===========*/ /* out: <0, 0 or >0; similar to strcmp(3) */ trx_t* a, /* in: the first transaction to be compared */ trx_t* b); /* in: the second transaction to be compared */ /* Signal to a transaction */ struct trx_sig_struct{ ulint type; /* signal type */ ulint sender; /* TRX_SIG_SELF or TRX_SIG_OTHER_SESS */ que_thr_t* receiver; /* non-NULL if the sender of the signal wants reply after the operation induced by the signal is completed */ trx_savept_t savept; /* possible rollback savepoint */ UT_LIST_NODE_T(trx_sig_t) signals; /* queue of pending signals to the transaction */ UT_LIST_NODE_T(trx_sig_t) reply_signals; /* list of signals for which the sender transaction is waiting a reply */ }; #define TRX_MAGIC_N 91118598 /* The transaction handle; every session has a trx object which is freed only when the session is freed; in addition there may be session-less transactions rolling back after a database recovery */ struct trx_struct{ ulint magic_n; /* All the next fields are protected by the kernel mutex, except the undo logs which are protected by undo_mutex */ const char* op_info; /* English text describing the current operation, or an empty string */ unsigned is_purge:1; /* 0=user transaction, 1=purge */ ulint conc_state; /* state of the trx from the point of view of concurrency control: TRX_ACTIVE, TRX_COMMITTED_IN_MEMORY, ... */ time_t start_time; /* time the trx object was created or the state last time became TRX_ACTIVE */ ulint isolation_level;/* TRX_ISO_REPEATABLE_READ, ... */ ibool check_foreigns; /* normally TRUE, but if the user wants to suppress foreign key checks, (in table imports, for example) we set this FALSE */ ibool 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 */ dulint id; /* transaction id */ XID xid; /* X/Open XA transaction identification to identify a transaction branch */ ibool 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 */ dulint no; /* transaction serialization number == max trx id when the transaction is moved to COMMITTED_IN_MEMORY state */ ibool flush_log_later;/* when we commit the transaction in MySQL's binlog write, we will flush the log to disk later in a separate call */ ibool must_flush_log_later;/* this flag is set to TRUE in trx_commit_off_kernel() 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() */ dulint commit_lsn; /* lsn at the time of the commit */ ibool dict_operation; /* TRUE if the trx is used to create a table, create an index, or drop a table. This is a hint that the table may need to be dropped in crash recovery. */ dulint table_id; /* table id if the preceding field is TRUE */ /*------------------------------*/ unsigned duplicates:2; /* TRX_DUP_IGNORE | TRX_DUP_REPLACE */ unsigned active_trans:2; /* 1 - if a transaction in MySQL is active. 2 - if prepare_commit_mutex was taken */ void* mysql_thd; /* MySQL thread handle corresponding to this trx, or NULL */ char** mysql_query_str;/* pointer to the field in mysqld_thd which contains the pointer to the current SQL query string */ size_t* mysql_query_len;/* pointer to the length of the current SQL query string */ 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_longlong mysql_log_offset;/* if MySQL binlog is used, this field contains the end offset of the binlog entry */ os_thread_id_t mysql_thread_id;/* id of the MySQL thread associated with this transaction object */ ulint mysql_process_no;/* since in Linux, 'top' reports process id's and not thread id's, we store the process number too */ /*------------------------------*/ 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 */ ibool dict_operation_lock_mode; /* 0, RW_S_LATCH, or RW_X_LATCH: the latch mode trx currently holds on dict_operation_lock */ ibool 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.c 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 */ /*------------------------------*/ ibool 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 */ /*------------------------------*/ lock_t* auto_inc_lock; /* possible auto-inc lock reserved by the transaction; note that it is also in the lock list trx_locks */ UT_LIST_NODE_T(trx_t) trx_list; /* list of transactions */ UT_LIST_NODE_T(trx_t) mysql_trx_list; /* list of transactions created for MySQL */ /*------------------------------*/ ulint 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 the kernel mutex */ void* error_info; /* if the error number indicates a duplicate key error, a pointer to the problematic index is stored here */ sess_t* sess; /* session of the trx, NULL if none */ ulint que_state; /* TRX_QUE_RUNNING, TRX_QUE_LOCK_WAIT, ... */ 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 */ ulint n_active_thrs; /* number of active query threads */ ibool handling_signals;/* this is TRUE as long as the trx is handling signals */ que_t* graph_before_signal_handling; /* value of graph when signal handling for this trx started: this is used to return control to the original query graph for error processing */ trx_sig_t sig; /* one signal object can be allocated in this space, avoiding mem_alloc */ UT_LIST_BASE_NODE_T(trx_sig_t) signals; /* queue of processed or pending signals to the trx */ UT_LIST_BASE_NODE_T(trx_sig_t) reply_signals; /* list of signals sent by the query threads of this trx for which a thread is waiting for a reply; if this trx is killed, the reply requests in the list must be canceled */ /*------------------------------*/ lock_t* wait_lock; /* if trx execution state is TRX_QUE_LOCK_WAIT, this points to the lock request, otherwise this is NULL */ 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 */ time_t wait_started; /* lock wait started at this time */ UT_LIST_BASE_NODE_T(que_thr_t) wait_thrs; /* query threads belonging to this trx that are in the QUE_THR_LOCK_WAIT state */ ulint deadlock_mark; /* a mark field used in deadlock checking algorithm */ /*------------------------------*/ mem_heap_t* lock_heap; /* memory heap for the locks of the transaction */ UT_LIST_BASE_NODE_T(lock_t) trx_locks; /* locks reserved by the transaction */ /*------------------------------*/ 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 */ /*------------------------------*/ 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! */ dulint 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 */ dulint 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 */ /*------------------------------*/ char detailed_error[256]; /* detailed error message for last error, or empty. */ }; #define TRX_MAX_N_THREADS 32 /* maximum number of concurrent threads running a single operation of a transaction, e.g., a parallel query */ /* Transaction concurrency states (trx->conc_state) */ #define TRX_NOT_STARTED 1 #define TRX_ACTIVE 2 #define TRX_COMMITTED_IN_MEMORY 3 #define TRX_PREPARED 4 /* Support for 2PC/XA */ /* Transaction execution states when trx->conc_state == TRX_ACTIVE */ #define TRX_QUE_RUNNING 1 /* transaction is running */ #define TRX_QUE_LOCK_WAIT 2 /* transaction is waiting for a lock */ #define TRX_QUE_ROLLING_BACK 3 /* transaction is rolling back */ #define TRX_QUE_COMMITTING 4 /* transaction is committing */ /* Transaction isolation levels (trx->isolation_level) */ #define TRX_ISO_READ_UNCOMMITTED 1 /* 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 2 /* 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 3 /* 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 4 /* 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 100 #define TRX_SIG_TOTAL_ROLLBACK 1 #define TRX_SIG_ROLLBACK_TO_SAVEPT 2 #define TRX_SIG_COMMIT 3 #define TRX_SIG_ERROR_OCCURRED 4 #define TRX_SIG_BREAK_EXECUTION 5 /* Sender types of a signal */ #define TRX_SIG_SELF 1 /* sent by the session itself, or by an error occurring within this session */ #define TRX_SIG_OTHER_SESS 2 /* sent by another session (which must hold rights to this) */ /* Commit command node in a query graph */ struct commit_node_struct{ que_common_t common; /* node type: QUE_NODE_COMMIT */ ulint state; /* node execution state */ }; /* Commit node states */ #define COMMIT_NODE_SEND 1 #define COMMIT_NODE_WAIT 2 #ifndef UNIV_NONINL #include "trx0trx.ic" #endif #endif