/****************************************************** The database server main program NOTE: SQL Server 7 uses something which the documentation calls user mode scheduled threads (UMS threads). One such thread is usually allocated per processor. Win32 documentation does not know any UMS threads, which suggests that the concept is internal to SQL Server 7. It may mean that SQL Server 7 does all the scheduling of threads itself, even in i/o waits. We should maybe modify InnoDB to use the same technique, because thread switches within NT may be too slow. SQL Server 7 also mentions fibers, which are cooperatively scheduled threads. They can boost performance by 5 %, according to the Delaney and Soukup's book. Windows 2000 will have something called thread pooling (see msdn website), which we could possibly use. Another possibility could be to use some very fast user space thread library. This might confuse NT though. (c) 1995 Innobase Oy Created 10/8/1995 Heikki Tuuri *******************************************************/ /* Dummy comment */ #include "srv0srv.h" #include "ut0mem.h" #include "os0proc.h" #include "mem0mem.h" #include "mem0pool.h" #include "sync0sync.h" #include "thr0loc.h" #include "que0que.h" #include "srv0que.h" #include "log0recv.h" #include "pars0pars.h" #include "usr0sess.h" #include "lock0lock.h" #include "trx0purge.h" #include "ibuf0ibuf.h" #include "buf0flu.h" #include "btr0sea.h" #include "dict0load.h" #include "dict0boot.h" #include "srv0start.h" #include "row0mysql.h" #include "ha_prototypes.h" /* This is set to TRUE if the MySQL user has set it in MySQL; currently affects only FOREIGN KEY definition parsing */ ibool srv_lower_case_table_names = FALSE; /* The following counter is incremented whenever there is some user activity in the server */ ulint srv_activity_count = 0; /* The following is the maximum allowed duration of a lock wait. */ ulint srv_fatal_semaphore_wait_threshold = 600; /* How much data manipulation language (DML) statements need to be delayed, in microseconds, in order to reduce the lagging of the purge thread. */ ulint srv_dml_needed_delay = 0; ibool srv_lock_timeout_and_monitor_active = FALSE; ibool srv_error_monitor_active = FALSE; const char* srv_main_thread_op_info = ""; /* Prefix used by MySQL to indicate pre-5.1 table name encoding */ const char srv_mysql50_table_name_prefix[9] = "#mysql50#"; /* Server parameters which are read from the initfile */ /* The following three are dir paths which are catenated before file names, where the file name itself may also contain a path */ char* srv_data_home = NULL; #ifdef UNIV_LOG_ARCHIVE char* srv_arch_dir = NULL; #endif /* UNIV_LOG_ARCHIVE */ ibool srv_file_per_table = FALSE; /* store to its own file each table created by an user; data dictionary tables are in the system tablespace 0 */ ibool srv_locks_unsafe_for_binlog = FALSE; /* Place locks to records only i.e. do not use next-key locking except on duplicate key checking and foreign key checking */ ulint srv_n_data_files = 0; char** srv_data_file_names = NULL; ulint* srv_data_file_sizes = NULL; /* size in database pages */ ibool srv_auto_extend_last_data_file = FALSE; /* if TRUE, then we auto-extend the last data file */ ulint srv_last_file_size_max = 0; /* if != 0, this tells the max size auto-extending may increase the last data file size */ ulong srv_auto_extend_increment = 8; /* If the last data file is auto-extended, we add this many pages to it at a time */ ulint* srv_data_file_is_raw_partition = NULL; /* If the following is TRUE we do not allow inserts etc. This protects the user from forgetting the 'newraw' keyword to my.cnf */ ibool srv_created_new_raw = FALSE; char** srv_log_group_home_dirs = NULL; ulint srv_n_log_groups = ULINT_MAX; ulint srv_n_log_files = ULINT_MAX; ulint srv_log_file_size = ULINT_MAX; /* size in database pages */ ulint srv_log_buffer_size = ULINT_MAX; /* size in database pages */ ulong srv_flush_log_at_trx_commit = 1; byte srv_latin1_ordering[256] /* The sort order table of the latin1 character set. The following table is the MySQL order as of Feb 10th, 2002 */ = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 , 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F , 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17 , 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F , 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27 , 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F , 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37 , 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F , 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 , 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F , 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57 , 0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F , 0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 , 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F , 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57 , 0x58, 0x59, 0x5A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F , 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87 , 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F , 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97 , 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F , 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7 , 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF , 0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7 , 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF , 0x41, 0x41, 0x41, 0x41, 0x5C, 0x5B, 0x5C, 0x43 , 0x45, 0x45, 0x45, 0x45, 0x49, 0x49, 0x49, 0x49 , 0x44, 0x4E, 0x4F, 0x4F, 0x4F, 0x4F, 0x5D, 0xD7 , 0xD8, 0x55, 0x55, 0x55, 0x59, 0x59, 0xDE, 0xDF , 0x41, 0x41, 0x41, 0x41, 0x5C, 0x5B, 0x5C, 0x43 , 0x45, 0x45, 0x45, 0x45, 0x49, 0x49, 0x49, 0x49 , 0x44, 0x4E, 0x4F, 0x4F, 0x4F, 0x4F, 0x5D, 0xF7 , 0xD8, 0x55, 0x55, 0x55, 0x59, 0x59, 0xDE, 0xFF }; ulint srv_pool_size = ULINT_MAX; /* size in pages; MySQL inits this to size in kilobytes but we normalize this to pages in srv_boot() */ ulint srv_awe_window_size = 0; /* size in pages; MySQL inits this to bytes, but we normalize it to pages in srv_boot() */ ulint srv_mem_pool_size = ULINT_MAX; /* size in bytes */ ulint srv_lock_table_size = ULINT_MAX; ulint srv_n_file_io_threads = ULINT_MAX; #ifdef UNIV_LOG_ARCHIVE ibool srv_log_archive_on = FALSE; ibool srv_archive_recovery = 0; dulint srv_archive_recovery_limit_lsn; #endif /* UNIV_LOG_ARCHIVE */ ulint srv_lock_wait_timeout = 1024 * 1024 * 1024; /* This parameter is used to throttle the number of insert buffers that are merged in a batch. By increasing this parameter on a faster disk you can possibly reduce the number of I/O operations performed to complete the merge operation. The value of this parameter is used as is by the background loop when the system is idle (low load), on a busy system the parameter is scaled down by a factor of 4, this is to avoid putting a heavier load on the I/O sub system. */ ulong srv_insert_buffer_batch_size = 20; char* srv_file_flush_method_str = NULL; ulint srv_unix_file_flush_method = SRV_UNIX_FSYNC; ulint srv_win_file_flush_method = SRV_WIN_IO_UNBUFFERED; ulint srv_max_n_open_files = 300; /* The InnoDB main thread tries to keep the ratio of modified pages in the buffer pool to all database pages in the buffer pool smaller than the following number. But it is not guaranteed that the value stays below that during a time of heavy update/insert activity. */ ulong srv_max_buf_pool_modified_pct = 90; /* variable counts amount of data read in total (in bytes) */ ulint srv_data_read = 0; /* here we count the amount of data written in total (in bytes) */ ulint srv_data_written = 0; /* the number of the log write requests done */ ulint srv_log_write_requests = 0; /* the number of physical writes to the log performed */ ulint srv_log_writes = 0; /* amount of data written to the log files in bytes */ ulint srv_os_log_written = 0; /* amount of writes being done to the log files */ ulint srv_os_log_pending_writes = 0; /* we increase this counter, when there we don't have enough space in the log buffer and have to flush it */ ulint srv_log_waits = 0; /* this variable counts the amount of times, when the doublewrite buffer was flushed */ ulint srv_dblwr_writes = 0; /* here we store the number of pages that have been flushed to the doublewrite buffer */ ulint srv_dblwr_pages_written = 0; /* in this variable we store the number of write requests issued */ ulint srv_buf_pool_write_requests = 0; /* here we store the number of times when we had to wait for a free page in the buffer pool. It happens when the buffer pool is full and we need to make a flush, in order to be able to read or create a page. */ ulint srv_buf_pool_wait_free = 0; /* variable to count the number of pages that were written from buffer pool to the disk */ ulint srv_buf_pool_flushed = 0; /* variable to count the number of buffer pool reads that led to the reading of a disk page */ ulint srv_buf_pool_reads = 0; /* variable to count the number of sequential read-aheads */ ulint srv_read_ahead_seq = 0; /* variable to count the number of random read-aheads */ ulint srv_read_ahead_rnd = 0; /* structure to pass status variables to MySQL */ export_struc export_vars; /* If the following is != 0 we do not allow inserts etc. This protects the user from forgetting the innodb_force_recovery keyword to my.cnf */ ulint srv_force_recovery = 0; /*-----------------------*/ /* We are prepared for a situation that we have this many threads waiting for a semaphore inside InnoDB. innobase_start_or_create_for_mysql() sets the value. */ ulint srv_max_n_threads = 0; /* The following controls how many threads we let inside InnoDB concurrently: threads waiting for locks are not counted into the number because otherwise we could get a deadlock. MySQL creates a thread for each user session, and semaphore contention and convoy problems can occur withput this restriction. Value 10 should be good if there are less than 4 processors + 4 disks in the computer. Bigger computers need bigger values. Value 0 will disable the concurrency check. */ ulong srv_thread_concurrency = 0; ulong srv_commit_concurrency = 0; os_fast_mutex_t srv_conc_mutex; /* this mutex protects srv_conc data structures */ lint srv_conc_n_threads = 0; /* number of OS threads currently inside InnoDB; it is not an error if this drops temporarily below zero because we do not demand that every thread increments this, but a thread waiting for a lock decrements this temporarily */ ulint srv_conc_n_waiting_threads = 0; /* number of OS threads waiting in the FIFO for a permission to enter InnoDB */ typedef struct srv_conc_slot_struct srv_conc_slot_t; struct srv_conc_slot_struct{ os_event_t event; /* event to wait */ ibool reserved; /* TRUE if slot reserved */ ibool wait_ended; /* TRUE when another thread has already set the event and the thread in this slot is free to proceed; but reserved may still be TRUE at that point */ UT_LIST_NODE_T(srv_conc_slot_t) srv_conc_queue; /* queue node */ }; UT_LIST_BASE_NODE_T(srv_conc_slot_t) srv_conc_queue; /* queue of threads waiting to get in */ srv_conc_slot_t* srv_conc_slots; /* array of wait slots */ /* Number of times a thread is allowed to enter InnoDB within the same SQL query after it has once got the ticket at srv_conc_enter_innodb */ #define SRV_FREE_TICKETS_TO_ENTER srv_n_free_tickets_to_enter #define SRV_THREAD_SLEEP_DELAY srv_thread_sleep_delay /*-----------------------*/ /* If the following is set to 1 then we do not run purge and insert buffer merge to completion before shutdown. If it is set to 2, do not even flush the buffer pool to data files at the shutdown: we effectively 'crash' InnoDB (but lose no committed transactions). */ ulint srv_fast_shutdown = 0; /* Generate a innodb_status. file */ ibool srv_innodb_status = FALSE; ibool srv_stats_on_metadata = TRUE; ibool srv_use_doublewrite_buf = TRUE; ibool srv_use_checksums = TRUE; ibool srv_set_thread_priorities = TRUE; int srv_query_thread_priority = 0; /* TRUE if the Address Windowing Extensions of Windows are used; then we must disable adaptive hash indexes */ ibool srv_use_awe = FALSE; ibool srv_use_adaptive_hash_indexes = TRUE; /*-------------------------------------------*/ ulong srv_n_spin_wait_rounds = 20; ulong srv_n_free_tickets_to_enter = 500; ulong srv_thread_sleep_delay = 10000; ulint srv_spin_wait_delay = 5; ibool srv_priority_boost = TRUE; ibool srv_print_thread_releases = FALSE; ibool srv_print_lock_waits = FALSE; ibool srv_print_buf_io = FALSE; ibool srv_print_log_io = FALSE; ibool srv_print_latch_waits = FALSE; ulint srv_n_rows_inserted = 0; ulint srv_n_rows_updated = 0; ulint srv_n_rows_deleted = 0; ulint srv_n_rows_read = 0; #ifndef UNIV_HOTBACKUP static ulint srv_n_rows_inserted_old = 0; static ulint srv_n_rows_updated_old = 0; static ulint srv_n_rows_deleted_old = 0; static ulint srv_n_rows_read_old = 0; #endif /* !UNIV_HOTBACKUP */ ulint srv_n_lock_wait_count = 0; ulint srv_n_lock_wait_current_count = 0; ib_longlong srv_n_lock_wait_time = 0; ulint srv_n_lock_max_wait_time = 0; /* Set the following to 0 if you want InnoDB to write messages on stderr on startup/shutdown */ ibool srv_print_verbose_log = TRUE; ibool srv_print_innodb_monitor = FALSE; ibool srv_print_innodb_lock_monitor = FALSE; ibool srv_print_innodb_tablespace_monitor = FALSE; ibool srv_print_innodb_table_monitor = FALSE; /* Array of English strings describing the current state of an i/o handler thread */ const char* srv_io_thread_op_info[SRV_MAX_N_IO_THREADS]; const char* srv_io_thread_function[SRV_MAX_N_IO_THREADS]; time_t srv_last_monitor_time; mutex_t srv_innodb_monitor_mutex; /* Mutex for locking srv_monitor_file */ mutex_t srv_monitor_file_mutex; /* Temporary file for innodb monitor output */ FILE* srv_monitor_file; /* Mutex for locking srv_dict_tmpfile. This mutex has a very high rank; threads reserving it should not be holding any InnoDB latches. */ mutex_t srv_dict_tmpfile_mutex; /* Temporary file for output from the data dictionary */ FILE* srv_dict_tmpfile; /* Mutex for locking srv_misc_tmpfile. This mutex has a very low rank; threads reserving it should not acquire any further latches or sleep before releasing this one. */ mutex_t srv_misc_tmpfile_mutex; /* Temporary file for miscellanous diagnostic output */ FILE* srv_misc_tmpfile; ulint srv_main_thread_process_no = 0; ulint srv_main_thread_id = 0; /* IMPLEMENTATION OF THE SERVER MAIN PROGRAM ========================================= There is the following analogue between this database server and an operating system kernel: DB concept equivalent OS concept ---------- --------------------- transaction -- process; query thread -- thread; lock -- semaphore; transaction set to the rollback state -- kill signal delivered to a process; kernel -- kernel; query thread execution: (a) without kernel mutex reserved -- process executing in user mode; (b) with kernel mutex reserved -- process executing in kernel mode; The server is controlled by a master thread which runs at a priority higher than normal, that is, higher than user threads. It sleeps most of the time, and wakes up, say, every 300 milliseconds, to check whether there is anything happening in the server which requires intervention of the master thread. Such situations may be, for example, when flushing of dirty blocks is needed in the buffer pool or old version of database rows have to be cleaned away. The threads which we call user threads serve the queries of the clients and input from the console of the server. They run at normal priority. The server may have several communications endpoints. A dedicated set of user threads waits at each of these endpoints ready to receive a client request. Each request is taken by a single user thread, which then starts processing and, when the result is ready, sends it to the client and returns to wait at the same endpoint the thread started from. So, we do not have dedicated communication threads listening at the endpoints and dealing the jobs to dedicated worker threads. Our architecture saves one thread swithch per request, compared to the solution with dedicated communication threads which amounts to 15 microseconds on 100 MHz Pentium running NT. If the client is communicating over a network, this saving is negligible, but if the client resides in the same machine, maybe in an SMP machine on a different processor from the server thread, the saving can be important as the threads can communicate over shared memory with an overhead of a few microseconds. We may later implement a dedicated communication thread solution for those endpoints which communicate over a network. Our solution with user threads has two problems: for each endpoint there has to be a number of listening threads. If there are many communication endpoints, it may be difficult to set the right number of concurrent threads in the system, as many of the threads may always be waiting at less busy endpoints. Another problem is queuing of the messages, as the server internally does not offer any queue for jobs. Another group of user threads is intended for splitting the queries and processing them in parallel. Let us call these parallel communication threads. These threads are waiting for parallelized tasks, suspended on event semaphores. A single user thread waits for input from the console, like a command to shut the database. Utility threads are a different group of threads which takes care of the buffer pool flushing and other, mainly background operations, in the server. Some of these utility threads always run at a lower than normal priority, so that they are always in background. Some of them may dynamically boost their priority by the pri_adjust function, even to higher than normal priority, if their task becomes urgent. The running of utilities is controlled by high- and low-water marks of urgency. The urgency may be measured by the number of dirty blocks in the buffer pool, in the case of the flush thread, for example. When the high-water mark is exceeded, an utility starts running, until the urgency drops under the low-water mark. Then the utility thread suspend itself to wait for an event. The master thread is responsible of signaling this event when the utility thread is again needed. For each individual type of utility, some threads always remain at lower than normal priority. This is because pri_adjust is implemented so that the threads at normal or higher priority control their share of running time by calling sleep. Thus, if the load of the system sudenly drops, these threads cannot necessarily utilize the system fully. The background priority threads make up for this, starting to run when the load drops. When there is no activity in the system, also the master thread suspends itself to wait for an event making the server totally silent. The responsibility to signal this event is on the user thread which again receives a message from a client. There is still one complication in our server design. If a background utility thread obtains a resource (e.g., mutex) needed by a user thread, and there is also some other user activity in the system, the user thread may have to wait indefinitely long for the resource, as the OS does not schedule a background thread if there is some other runnable user thread. This problem is called priority inversion in real-time programming. One solution to the priority inversion problem would be to keep record of which thread owns which resource and in the above case boost the priority of the background thread so that it will be scheduled and it can release the resource. This solution is called priority inheritance in real-time programming. A drawback of this solution is that the overhead of acquiring a mutex increases slightly, maybe 0.2 microseconds on a 100 MHz Pentium, because the thread has to call os_thread_get_curr_id. This may be compared to 0.5 microsecond overhead for a mutex lock-unlock pair. Note that the thread cannot store the information in the resource, say mutex, itself, because competing threads could wipe out the information if it is stored before acquiring the mutex, and if it stored afterwards, the information is outdated for the time of one machine instruction, at least. (To be precise, the information could be stored to lock_word in mutex if the machine supports atomic swap.) The above solution with priority inheritance may become actual in the future, but at the moment we plan to implement a more coarse solution, which could be called a global priority inheritance. If a thread has to wait for a long time, say 300 milliseconds, for a resource, we just guess that it may be waiting for a resource owned by a background thread, and boost the the priority of all runnable background threads to the normal level. The background threads then themselves adjust their fixed priority back to background after releasing all resources they had (or, at some fixed points in their program code). What is the performance of the global priority inheritance solution? We may weigh the length of the wait time 300 milliseconds, during which the system processes some other thread to the cost of boosting the priority of each runnable background thread, rescheduling it, and lowering the priority again. On 100 MHz Pentium + NT this overhead may be of the order 100 microseconds per thread. So, if the number of runnable background threads is not very big, say < 100, the cost is tolerable. Utility threads probably will access resources used by user threads not very often, so collisions of user threads to preempted utility threads should not happen very often. The thread table contains information of the current status of each thread existing in the system, and also the event semaphores used in suspending the master thread and utility and parallel communication threads when they have nothing to do. The thread table can be seen as an analogue to the process table in a traditional Unix implementation. The thread table is also used in the global priority inheritance scheme. This brings in one additional complication: threads accessing the thread table must have at least normal fixed priority, because the priority inheritance solution does not work if a background thread is preempted while possessing the mutex protecting the thread table. So, if a thread accesses the thread table, its priority has to be boosted at least to normal. This priority requirement can be seen similar to the privileged mode used when processing the kernel calls in traditional Unix.*/ /* Thread slot in the thread table */ struct srv_slot_struct{ os_thread_id_t id; /* thread id */ os_thread_t handle; /* thread handle */ ulint type; /* thread type: user, utility etc. */ ibool in_use; /* TRUE if this slot is in use */ ibool suspended; /* TRUE if the thread is waiting for the event of this slot */ ib_time_t suspend_time; /* time when the thread was suspended */ os_event_t event; /* event used in suspending the thread when it has nothing to do */ que_thr_t* thr; /* suspended query thread (only used for MySQL threads) */ }; /* Table for MySQL threads where they will be suspended to wait for locks */ srv_slot_t* srv_mysql_table = NULL; os_event_t srv_lock_timeout_thread_event; srv_sys_t* srv_sys = NULL; byte srv_pad1[64]; /* padding to prevent other memory update hotspots from residing on the same memory cache line */ mutex_t* kernel_mutex_temp;/* mutex protecting the server, trx structs, query threads, and lock table */ byte srv_pad2[64]; /* padding to prevent other memory update hotspots from residing on the same memory cache line */ /* The following three values measure the urgency of the jobs of buffer, version, and insert threads. They may vary from 0 - 1000. The server mutex protects all these variables. The low-water values tell that the server can acquiesce the utility when the value drops below this low-water mark. */ ulint srv_meter[SRV_MASTER + 1]; ulint srv_meter_low_water[SRV_MASTER + 1]; ulint srv_meter_high_water[SRV_MASTER + 1]; ulint srv_meter_high_water2[SRV_MASTER + 1]; ulint srv_meter_foreground[SRV_MASTER + 1]; /* The following values give info about the activity going on in the database. They are protected by the server mutex. The arrays are indexed by the type of the thread. */ ulint srv_n_threads_active[SRV_MASTER + 1]; ulint srv_n_threads[SRV_MASTER + 1]; /************************************************************************* Sets the info describing an i/o thread current state. */ void srv_set_io_thread_op_info( /*======================*/ ulint i, /* in: the 'segment' of the i/o thread */ const char* str) /* in: constant char string describing the state */ { ut_a(i < SRV_MAX_N_IO_THREADS); srv_io_thread_op_info[i] = str; } /************************************************************************* Accessor function to get pointer to n'th slot in the server thread table. */ static srv_slot_t* srv_table_get_nth_slot( /*===================*/ /* out: pointer to the slot */ ulint index) /* in: index of the slot */ { ut_a(index < OS_THREAD_MAX_N); return(srv_sys->threads + index); } #ifndef UNIV_HOTBACKUP /************************************************************************* Gets the number of threads in the system. */ ulint srv_get_n_threads(void) /*===================*/ { ulint i; ulint n_threads = 0; mutex_enter(&kernel_mutex); for (i = SRV_COM; i < SRV_MASTER + 1; i++) { n_threads += srv_n_threads[i]; } mutex_exit(&kernel_mutex); return(n_threads); } /************************************************************************* Reserves a slot in the thread table for the current thread. Also creates the thread local storage struct for the current thread. NOTE! The server mutex has to be reserved by the caller! */ static ulint srv_table_reserve_slot( /*===================*/ /* out: reserved slot index */ ulint type) /* in: type of the thread: one of SRV_COM, ... */ { srv_slot_t* slot; ulint i; ut_a(type > 0); ut_a(type <= SRV_MASTER); i = 0; slot = srv_table_get_nth_slot(i); while (slot->in_use) { i++; slot = srv_table_get_nth_slot(i); } ut_a(slot->in_use == FALSE); slot->in_use = TRUE; slot->suspended = FALSE; slot->id = os_thread_get_curr_id(); slot->handle = os_thread_get_curr(); slot->type = type; thr_local_create(); thr_local_set_slot_no(os_thread_get_curr_id(), i); return(i); } /************************************************************************* Suspends the calling thread to wait for the event in its thread slot. NOTE! The server mutex has to be reserved by the caller! */ static os_event_t srv_suspend_thread(void) /*====================*/ /* out: event for the calling thread to wait */ { srv_slot_t* slot; os_event_t event; ulint slot_no; ulint type; ut_ad(mutex_own(&kernel_mutex)); slot_no = thr_local_get_slot_no(os_thread_get_curr_id()); if (srv_print_thread_releases) { fprintf(stderr, "Suspending thread %lu to slot %lu meter %lu\n", (ulong) os_thread_get_curr_id(), (ulong) slot_no, (ulong) srv_meter[SRV_RECOVERY]); } slot = srv_table_get_nth_slot(slot_no); type = slot->type; ut_ad(type >= SRV_WORKER); ut_ad(type <= SRV_MASTER); event = slot->event; slot->suspended = TRUE; ut_ad(srv_n_threads_active[type] > 0); srv_n_threads_active[type]--; os_event_reset(event); return(event); } #endif /* !UNIV_HOTBACKUP */ /************************************************************************* Releases threads of the type given from suspension in the thread table. NOTE! The server mutex has to be reserved by the caller! */ ulint srv_release_threads( /*================*/ /* out: number of threads released: this may be < n if not enough threads were suspended at the moment */ ulint type, /* in: thread type */ ulint n) /* in: number of threads to release */ { srv_slot_t* slot; ulint i; ulint count = 0; ut_ad(type >= SRV_WORKER); ut_ad(type <= SRV_MASTER); ut_ad(n > 0); ut_ad(mutex_own(&kernel_mutex)); for (i = 0; i < OS_THREAD_MAX_N; i++) { slot = srv_table_get_nth_slot(i); if (slot->in_use && slot->type == type && slot->suspended) { slot->suspended = FALSE; srv_n_threads_active[type]++; os_event_set(slot->event); if (srv_print_thread_releases) { fprintf(stderr, "Releasing thread %lu type %lu" " from slot %lu meter %lu\n", (ulong) slot->id, (ulong) type, (ulong) i, (ulong) srv_meter[SRV_RECOVERY]); } count++; if (count == n) { break; } } } return(count); } /************************************************************************* Returns the calling thread type. */ ulint srv_get_thread_type(void) /*=====================*/ /* out: SRV_COM, ... */ { ulint slot_no; srv_slot_t* slot; ulint type; mutex_enter(&kernel_mutex); slot_no = thr_local_get_slot_no(os_thread_get_curr_id()); slot = srv_table_get_nth_slot(slot_no); type = slot->type; ut_ad(type >= SRV_WORKER); ut_ad(type <= SRV_MASTER); mutex_exit(&kernel_mutex); return(type); } /************************************************************************* Initializes the server. */ void srv_init(void) /*==========*/ { srv_conc_slot_t* conc_slot; srv_slot_t* slot; dict_table_t* table; ulint i; srv_sys = mem_alloc(sizeof(srv_sys_t)); kernel_mutex_temp = mem_alloc(sizeof(mutex_t)); mutex_create(&kernel_mutex, SYNC_KERNEL); mutex_create(&srv_innodb_monitor_mutex, SYNC_NO_ORDER_CHECK); srv_sys->threads = mem_alloc(OS_THREAD_MAX_N * sizeof(srv_slot_t)); for (i = 0; i < OS_THREAD_MAX_N; i++) { slot = srv_table_get_nth_slot(i); slot->in_use = FALSE; slot->type=0; /* Avoid purify errors */ slot->event = os_event_create(NULL); ut_a(slot->event); } srv_mysql_table = mem_alloc(OS_THREAD_MAX_N * sizeof(srv_slot_t)); for (i = 0; i < OS_THREAD_MAX_N; i++) { slot = srv_mysql_table + i; slot->in_use = FALSE; slot->type = 0; slot->event = os_event_create(NULL); ut_a(slot->event); } srv_lock_timeout_thread_event = os_event_create(NULL); for (i = 0; i < SRV_MASTER + 1; i++) { srv_n_threads_active[i] = 0; srv_n_threads[i] = 0; srv_meter[i] = 30; srv_meter_low_water[i] = 50; srv_meter_high_water[i] = 100; srv_meter_high_water2[i] = 200; srv_meter_foreground[i] = 250; } UT_LIST_INIT(srv_sys->tasks); /* create dummy table and index for old-style infimum and supremum */ table = dict_mem_table_create("SYS_DUMMY1", DICT_HDR_SPACE, 1, 0); dict_mem_table_add_col(table, NULL, NULL, DATA_CHAR, DATA_ENGLISH | DATA_NOT_NULL, 8); srv_sys->dummy_ind1 = dict_mem_index_create( "SYS_DUMMY1", "SYS_DUMMY1", DICT_HDR_SPACE, 0, 1); dict_index_add_col(srv_sys->dummy_ind1, table, (dict_col_t*) dict_table_get_nth_col(table, 0), 0); srv_sys->dummy_ind1->table = table; /* create dummy table and index for new-style infimum and supremum */ table = dict_mem_table_create("SYS_DUMMY2", DICT_HDR_SPACE, 1, DICT_TF_COMPACT); dict_mem_table_add_col(table, NULL, NULL, DATA_CHAR, DATA_ENGLISH | DATA_NOT_NULL, 8); srv_sys->dummy_ind2 = dict_mem_index_create( "SYS_DUMMY2", "SYS_DUMMY2", DICT_HDR_SPACE, 0, 1); dict_index_add_col(srv_sys->dummy_ind2, table, (dict_col_t*) dict_table_get_nth_col(table, 0), 0); srv_sys->dummy_ind2->table = table; /* avoid ut_ad(index->cached) in dict_index_get_n_unique_in_tree */ srv_sys->dummy_ind1->cached = srv_sys->dummy_ind2->cached = TRUE; /* Init the server concurrency restriction data structures */ os_fast_mutex_init(&srv_conc_mutex); UT_LIST_INIT(srv_conc_queue); srv_conc_slots = mem_alloc(OS_THREAD_MAX_N * sizeof(srv_conc_slot_t)); for (i = 0; i < OS_THREAD_MAX_N; i++) { conc_slot = srv_conc_slots + i; conc_slot->reserved = FALSE; conc_slot->event = os_event_create(NULL); ut_a(conc_slot->event); } } /************************************************************************* Frees the OS fast mutex created in srv_init(). */ void srv_free(void) /*==========*/ { os_fast_mutex_free(&srv_conc_mutex); } /************************************************************************* Initializes the synchronization primitives, memory system, and the thread local storage. */ void srv_general_init(void) /*==================*/ { os_sync_init(); sync_init(); mem_init(srv_mem_pool_size); thr_local_init(); } /*======================= InnoDB Server FIFO queue =======================*/ /* Maximum allowable purge history length. <=0 means 'infinite'. */ ulong srv_max_purge_lag = 0; /************************************************************************* Puts an OS thread to wait if there are too many concurrent threads (>= srv_thread_concurrency) inside InnoDB. The threads wait in a FIFO queue. */ void srv_conc_enter_innodb( /*==================*/ trx_t* trx) /* in: transaction object associated with the thread */ { ibool has_slept = FALSE; srv_conc_slot_t* slot = NULL; ulint i; if (trx->mysql_thd != NULL && thd_is_replication_slave_thread(trx->mysql_thd)) { /* TODO Do something more interesting (based on a config parameter). Some users what to give the replication thread very low priority, see http://bugs.mysql.com/25078 This can be done by introducing innodb_replication_delay(ms) config parameter */ return; } /* If trx has 'free tickets' to enter the engine left, then use one such ticket */ if (trx->n_tickets_to_enter_innodb > 0) { trx->n_tickets_to_enter_innodb--; return; } os_fast_mutex_lock(&srv_conc_mutex); retry: if (trx->declared_to_be_inside_innodb) { ut_print_timestamp(stderr); fputs(" InnoDB: Error: trying to declare trx" " to enter InnoDB, but\n" "InnoDB: it already is declared.\n", stderr); trx_print(stderr, trx, 0); putc('\n', stderr); os_fast_mutex_unlock(&srv_conc_mutex); return; } if (srv_conc_n_threads < (lint)srv_thread_concurrency) { srv_conc_n_threads++; trx->declared_to_be_inside_innodb = TRUE; trx->n_tickets_to_enter_innodb = SRV_FREE_TICKETS_TO_ENTER; os_fast_mutex_unlock(&srv_conc_mutex); return; } /* If the transaction is not holding resources, let it sleep for SRV_THREAD_SLEEP_DELAY microseconds, and try again then */ if (!has_slept && !trx->has_search_latch && NULL == UT_LIST_GET_FIRST(trx->trx_locks)) { has_slept = TRUE; /* We let it sleep only once to avoid starvation */ srv_conc_n_waiting_threads++; os_fast_mutex_unlock(&srv_conc_mutex); trx->op_info = "sleeping before joining InnoDB queue"; /* Peter Zaitsev suggested that we take the sleep away altogether. But the sleep may be good in pathological situations of lots of thread switches. Simply put some threads aside for a while to reduce the number of thread switches. */ if (SRV_THREAD_SLEEP_DELAY > 0) { os_thread_sleep(SRV_THREAD_SLEEP_DELAY); } trx->op_info = ""; os_fast_mutex_lock(&srv_conc_mutex); srv_conc_n_waiting_threads--; goto retry; } /* Too many threads inside: put the current thread to a queue */ for (i = 0; i < OS_THREAD_MAX_N; i++) { slot = srv_conc_slots + i; if (!slot->reserved) { break; } } if (i == OS_THREAD_MAX_N) { /* Could not find a free wait slot, we must let the thread enter */ srv_conc_n_threads++; trx->declared_to_be_inside_innodb = TRUE; trx->n_tickets_to_enter_innodb = 0; os_fast_mutex_unlock(&srv_conc_mutex); return; } /* Release possible search system latch this thread has */ if (trx->has_search_latch) { trx_search_latch_release_if_reserved(trx); } /* Add to the queue */ slot->reserved = TRUE; slot->wait_ended = FALSE; UT_LIST_ADD_LAST(srv_conc_queue, srv_conc_queue, slot); os_event_reset(slot->event); srv_conc_n_waiting_threads++; os_fast_mutex_unlock(&srv_conc_mutex); /* Go to wait for the event; when a thread leaves InnoDB it will release this thread */ trx->op_info = "waiting in InnoDB queue"; os_event_wait(slot->event); trx->op_info = ""; os_fast_mutex_lock(&srv_conc_mutex); srv_conc_n_waiting_threads--; /* NOTE that the thread which released this thread already incremented the thread counter on behalf of this thread */ slot->reserved = FALSE; UT_LIST_REMOVE(srv_conc_queue, srv_conc_queue, slot); trx->declared_to_be_inside_innodb = TRUE; trx->n_tickets_to_enter_innodb = SRV_FREE_TICKETS_TO_ENTER; os_fast_mutex_unlock(&srv_conc_mutex); } /************************************************************************* This lets a thread enter InnoDB regardless of the number of threads inside InnoDB. This must be called when a thread ends a lock wait. */ void srv_conc_force_enter_innodb( /*========================*/ trx_t* trx) /* in: transaction object associated with the thread */ { if (UNIV_LIKELY(!srv_thread_concurrency)) { return; } os_fast_mutex_lock(&srv_conc_mutex); srv_conc_n_threads++; trx->declared_to_be_inside_innodb = TRUE; trx->n_tickets_to_enter_innodb = 1; os_fast_mutex_unlock(&srv_conc_mutex); } /************************************************************************* This must be called when a thread exits InnoDB in a lock wait or at the end of an SQL statement. */ void srv_conc_force_exit_innodb( /*=======================*/ trx_t* trx) /* in: transaction object associated with the thread */ { srv_conc_slot_t* slot = NULL; if (UNIV_LIKELY(!srv_thread_concurrency)) { return; } if (trx->mysql_thd != NULL && thd_is_replication_slave_thread(trx->mysql_thd)) { return; } if (trx->declared_to_be_inside_innodb == FALSE) { return; } os_fast_mutex_lock(&srv_conc_mutex); srv_conc_n_threads--; trx->declared_to_be_inside_innodb = FALSE; trx->n_tickets_to_enter_innodb = 0; if (srv_conc_n_threads < (lint)srv_thread_concurrency) { /* Look for a slot where a thread is waiting and no other thread has yet released the thread */ slot = UT_LIST_GET_FIRST(srv_conc_queue); while (slot && slot->wait_ended == TRUE) { slot = UT_LIST_GET_NEXT(srv_conc_queue, slot); } if (slot != NULL) { slot->wait_ended = TRUE; /* We increment the count on behalf of the released thread */ srv_conc_n_threads++; } } os_fast_mutex_unlock(&srv_conc_mutex); if (slot != NULL) { os_event_set(slot->event); } } /************************************************************************* This must be called when a thread exits InnoDB. */ void srv_conc_exit_innodb( /*=================*/ trx_t* trx) /* in: transaction object associated with the thread */ { if (trx->n_tickets_to_enter_innodb > 0) { /* We will pretend the thread is still inside InnoDB though it now leaves the InnoDB engine. In this way we save a lot of semaphore operations. srv_conc_force_exit_innodb is used to declare the thread definitely outside InnoDB. It should be called when there is a lock wait or an SQL statement ends. */ return; } srv_conc_force_exit_innodb(trx); } /*========================================================================*/ /************************************************************************* Normalizes init parameter values to use units we use inside InnoDB. */ static ulint srv_normalize_init_values(void) /*===========================*/ /* out: DB_SUCCESS or error code */ { ulint n; ulint i; n = srv_n_data_files; for (i = 0; i < n; i++) { srv_data_file_sizes[i] = srv_data_file_sizes[i] * ((1024 * 1024) / UNIV_PAGE_SIZE); } srv_last_file_size_max = srv_last_file_size_max * ((1024 * 1024) / UNIV_PAGE_SIZE); srv_log_file_size = srv_log_file_size / UNIV_PAGE_SIZE; srv_log_buffer_size = srv_log_buffer_size / UNIV_PAGE_SIZE; srv_pool_size = srv_pool_size / (UNIV_PAGE_SIZE / 1024); srv_awe_window_size = srv_awe_window_size / UNIV_PAGE_SIZE; if (srv_use_awe) { /* If we are using AWE we must save memory in the 32-bit address space of the process, and cannot bind the lock table size to the real buffer pool size. */ srv_lock_table_size = 20 * srv_awe_window_size; } else { srv_lock_table_size = 5 * srv_pool_size; } return(DB_SUCCESS); } /************************************************************************* Boots the InnoDB server. */ ulint srv_boot(void) /*==========*/ /* out: DB_SUCCESS or error code */ { ulint err; /* Transform the init parameter values given by MySQL to use units we use inside InnoDB: */ err = srv_normalize_init_values(); if (err != DB_SUCCESS) { return(err); } /* Initialize synchronization primitives, memory management, and thread local storage */ srv_general_init(); /* Initialize this module */ srv_init(); return(DB_SUCCESS); } #ifndef UNIV_HOTBACKUP /************************************************************************* Reserves a slot in the thread table for the current MySQL OS thread. NOTE! The kernel mutex has to be reserved by the caller! */ static srv_slot_t* srv_table_reserve_slot_for_mysql(void) /*==================================*/ /* out: reserved slot */ { srv_slot_t* slot; ulint i; ut_ad(mutex_own(&kernel_mutex)); i = 0; slot = srv_mysql_table + i; while (slot->in_use) { i++; if (i >= OS_THREAD_MAX_N) { ut_print_timestamp(stderr); fprintf(stderr, " InnoDB: There appear to be %lu MySQL" " threads currently waiting\n" "InnoDB: inside InnoDB, which is the" " upper limit. Cannot continue operation.\n" "InnoDB: We intentionally generate" " a seg fault to print a stack trace\n" "InnoDB: on Linux. But first we print" " a list of waiting threads.\n", (ulong) i); for (i = 0; i < OS_THREAD_MAX_N; i++) { slot = srv_mysql_table + i; fprintf(stderr, "Slot %lu: thread id %lu, type %lu," " in use %lu, susp %lu, time %lu\n", (ulong) i, (ulong) os_thread_pf(slot->id), (ulong) slot->type, (ulong) slot->in_use, (ulong) slot->suspended, (ulong) difftime(ut_time(), slot->suspend_time)); } ut_error; } slot = srv_mysql_table + i; } ut_a(slot->in_use == FALSE); slot->in_use = TRUE; slot->id = os_thread_get_curr_id(); slot->handle = os_thread_get_curr(); return(slot); } #endif /* !UNIV_HOTBACKUP */ /******************************************************************* Puts a MySQL OS thread to wait for a lock to be released. If an error occurs during the wait trx->error_state associated with thr is != DB_SUCCESS when we return. DB_LOCK_WAIT_TIMEOUT and DB_DEADLOCK are possible errors. DB_DEADLOCK is returned if selective deadlock resolution chose this transaction as a victim. */ void srv_suspend_mysql_thread( /*=====================*/ que_thr_t* thr) /* in: query thread associated with the MySQL OS thread */ { #ifndef UNIV_HOTBACKUP srv_slot_t* slot; os_event_t event; double wait_time; trx_t* trx; ibool had_dict_lock = FALSE; ibool was_declared_inside_innodb = FALSE; ib_longlong start_time = 0; ib_longlong finish_time; ulint diff_time; ulint sec; ulint ms; ut_ad(!mutex_own(&kernel_mutex)); trx = thr_get_trx(thr); os_event_set(srv_lock_timeout_thread_event); mutex_enter(&kernel_mutex); trx->error_state = DB_SUCCESS; if (thr->state == QUE_THR_RUNNING) { ut_ad(thr->is_active == TRUE); /* The lock has already been released or this transaction was chosen as a deadlock victim: no need to suspend */ if (trx->was_chosen_as_deadlock_victim) { trx->error_state = DB_DEADLOCK; trx->was_chosen_as_deadlock_victim = FALSE; } mutex_exit(&kernel_mutex); return; } ut_ad(thr->is_active == FALSE); slot = srv_table_reserve_slot_for_mysql(); event = slot->event; slot->thr = thr; os_event_reset(event); slot->suspend_time = ut_time(); if (thr->lock_state == QUE_THR_LOCK_ROW) { srv_n_lock_wait_count++; srv_n_lock_wait_current_count++; ut_usectime(&sec, &ms); start_time = (ib_longlong)sec * 1000000 + ms; } /* Wake the lock timeout monitor thread, if it is suspended */ os_event_set(srv_lock_timeout_thread_event); mutex_exit(&kernel_mutex); if (trx->declared_to_be_inside_innodb) { was_declared_inside_innodb = TRUE; /* We must declare this OS thread to exit InnoDB, since a possible other thread holding a lock which this thread waits for must be allowed to enter, sooner or later */ srv_conc_force_exit_innodb(trx); } /* Release possible foreign key check latch */ if (trx->dict_operation_lock_mode == RW_S_LATCH) { had_dict_lock = TRUE; row_mysql_unfreeze_data_dictionary(trx); } ut_a(trx->dict_operation_lock_mode == 0); /* Wait for the release */ os_event_wait(event); if (had_dict_lock) { row_mysql_freeze_data_dictionary(trx); } if (was_declared_inside_innodb) { /* Return back inside InnoDB */ srv_conc_force_enter_innodb(trx); } mutex_enter(&kernel_mutex); /* Release the slot for others to use */ slot->in_use = FALSE; wait_time = ut_difftime(ut_time(), slot->suspend_time); if (thr->lock_state == QUE_THR_LOCK_ROW) { ut_usectime(&sec, &ms); finish_time = (ib_longlong)sec * 1000000 + ms; diff_time = (ulint) (finish_time - start_time); srv_n_lock_wait_current_count--; srv_n_lock_wait_time = srv_n_lock_wait_time + diff_time; if (diff_time > srv_n_lock_max_wait_time) { srv_n_lock_max_wait_time = diff_time; } } if (trx->was_chosen_as_deadlock_victim) { trx->error_state = DB_DEADLOCK; trx->was_chosen_as_deadlock_victim = FALSE; } mutex_exit(&kernel_mutex); if (srv_lock_wait_timeout < 100000000 && wait_time > (double)srv_lock_wait_timeout) { trx->error_state = DB_LOCK_WAIT_TIMEOUT; } #else /* UNIV_HOTBACKUP */ /* This function depends on MySQL code that is not included in InnoDB Hot Backup builds. Besides, this function should never be called in InnoDB Hot Backup. */ ut_error; #endif /* UNIV_HOTBACKUP */ } /************************************************************************ Releases a MySQL OS thread waiting for a lock to be released, if the thread is already suspended. */ void srv_release_mysql_thread_if_suspended( /*==================================*/ que_thr_t* thr) /* in: query thread associated with the MySQL OS thread */ { #ifndef UNIV_HOTBACKUP srv_slot_t* slot; ulint i; ut_ad(mutex_own(&kernel_mutex)); for (i = 0; i < OS_THREAD_MAX_N; i++) { slot = srv_mysql_table + i; if (slot->in_use && slot->thr == thr) { /* Found */ os_event_set(slot->event); return; } } /* not found */ #else /* UNIV_HOTBACKUP */ /* This function depends on MySQL code that is not included in InnoDB Hot Backup builds. Besides, this function should never be called in InnoDB Hot Backup. */ ut_error; #endif /* UNIV_HOTBACKUP */ } #ifndef UNIV_HOTBACKUP /********************************************************************** Refreshes the values used to calculate per-second averages. */ static void srv_refresh_innodb_monitor_stats(void) /*==================================*/ { mutex_enter(&srv_innodb_monitor_mutex); srv_last_monitor_time = time(NULL); os_aio_refresh_stats(); btr_cur_n_sea_old = btr_cur_n_sea; btr_cur_n_non_sea_old = btr_cur_n_non_sea; log_refresh_stats(); buf_refresh_io_stats(); srv_n_rows_inserted_old = srv_n_rows_inserted; srv_n_rows_updated_old = srv_n_rows_updated; srv_n_rows_deleted_old = srv_n_rows_deleted; srv_n_rows_read_old = srv_n_rows_read; mutex_exit(&srv_innodb_monitor_mutex); } /********************************************************************** Outputs to a file the output of the InnoDB Monitor. */ void srv_printf_innodb_monitor( /*======================*/ FILE* file, /* in: output stream */ ulint* trx_start, /* out: file position of the start of the list of active transactions */ ulint* trx_end) /* out: file position of the end of the list of active transactions */ { double time_elapsed; time_t current_time; ulint n_reserved; mutex_enter(&srv_innodb_monitor_mutex); current_time = time(NULL); /* We add 0.001 seconds to time_elapsed to prevent division by zero if two users happen to call SHOW INNODB STATUS at the same time */ time_elapsed = difftime(current_time, srv_last_monitor_time) + 0.001; srv_last_monitor_time = time(NULL); fputs("\n=====================================\n", file); ut_print_timestamp(file); fprintf(file, " INNODB MONITOR OUTPUT\n" "=====================================\n" "Per second averages calculated from the last %lu seconds\n", (ulong)time_elapsed); fputs("----------\n" "SEMAPHORES\n" "----------\n", file); sync_print(file); /* Conceptually, srv_innodb_monitor_mutex has a very high latching order level in sync0sync.h, while dict_foreign_err_mutex has a very low level 135. Therefore we can reserve the latter mutex here without a danger of a deadlock of threads. */ mutex_enter(&dict_foreign_err_mutex); if (ftell(dict_foreign_err_file) != 0L) { fputs("------------------------\n" "LATEST FOREIGN KEY ERROR\n" "------------------------\n", file); ut_copy_file(file, dict_foreign_err_file); } mutex_exit(&dict_foreign_err_mutex); lock_print_info_summary(file); if (trx_start) { long t = ftell(file); if (t < 0) { *trx_start = ULINT_UNDEFINED; } else { *trx_start = (ulint) t; } } lock_print_info_all_transactions(file); if (trx_end) { long t = ftell(file); if (t < 0) { *trx_end = ULINT_UNDEFINED; } else { *trx_end = (ulint) t; } } fputs("--------\n" "FILE I/O\n" "--------\n", file); os_aio_print(file); fputs("-------------------------------------\n" "INSERT BUFFER AND ADAPTIVE HASH INDEX\n" "-------------------------------------\n", file); ibuf_print(file); ha_print_info(file, btr_search_sys->hash_index); fprintf(file, "%.2f hash searches/s, %.2f non-hash searches/s\n", (btr_cur_n_sea - btr_cur_n_sea_old) / time_elapsed, (btr_cur_n_non_sea - btr_cur_n_non_sea_old) / time_elapsed); btr_cur_n_sea_old = btr_cur_n_sea; btr_cur_n_non_sea_old = btr_cur_n_non_sea; fputs("---\n" "LOG\n" "---\n", file); log_print(file); fputs("----------------------\n" "BUFFER POOL AND MEMORY\n" "----------------------\n", file); fprintf(file, "Total memory allocated " ULINTPF "; in additional pool allocated " ULINTPF "\n", ut_total_allocated_memory, mem_pool_get_reserved(mem_comm_pool)); fprintf(file, "Dictionary memory allocated " ULINTPF "\n", dict_sys->size); if (srv_use_awe) { fprintf(file, "In addition to that %lu MB of AWE memory allocated\n", (ulong) (srv_pool_size / ((1024 * 1024) / UNIV_PAGE_SIZE))); } buf_print_io(file); fputs("--------------\n" "ROW OPERATIONS\n" "--------------\n", file); fprintf(file, "%ld queries inside InnoDB, %lu queries in queue\n", (long) srv_conc_n_threads, (ulong) srv_conc_n_waiting_threads); fprintf(file, "%lu read views open inside InnoDB\n", UT_LIST_GET_LEN(trx_sys->view_list)); n_reserved = fil_space_get_n_reserved_extents(0); if (n_reserved > 0) { fprintf(file, "%lu tablespace extents now reserved for" " B-tree split operations\n", (ulong) n_reserved); } #ifdef UNIV_LINUX fprintf(file, "Main thread process no. %lu, id %lu, state: %s\n", (ulong) srv_main_thread_process_no, (ulong) srv_main_thread_id, srv_main_thread_op_info); #else fprintf(file, "Main thread id %lu, state: %s\n", (ulong) srv_main_thread_id, srv_main_thread_op_info); #endif fprintf(file, "Number of rows inserted " ULINTPF ", updated " ULINTPF ", deleted " ULINTPF ", read " ULINTPF "\n", srv_n_rows_inserted, srv_n_rows_updated, srv_n_rows_deleted, srv_n_rows_read); fprintf(file, "%.2f inserts/s, %.2f updates/s," " %.2f deletes/s, %.2f reads/s\n", (srv_n_rows_inserted - srv_n_rows_inserted_old) / time_elapsed, (srv_n_rows_updated - srv_n_rows_updated_old) / time_elapsed, (srv_n_rows_deleted - srv_n_rows_deleted_old) / time_elapsed, (srv_n_rows_read - srv_n_rows_read_old) / time_elapsed); srv_n_rows_inserted_old = srv_n_rows_inserted; srv_n_rows_updated_old = srv_n_rows_updated; srv_n_rows_deleted_old = srv_n_rows_deleted; srv_n_rows_read_old = srv_n_rows_read; fputs("----------------------------\n" "END OF INNODB MONITOR OUTPUT\n" "============================\n", file); mutex_exit(&srv_innodb_monitor_mutex); fflush(file); } /********************************************************************** Function to pass InnoDB status variables to MySQL */ void srv_export_innodb_status(void) { mutex_enter(&srv_innodb_monitor_mutex); export_vars.innodb_data_pending_reads = os_n_pending_reads; export_vars.innodb_data_pending_writes = os_n_pending_writes; export_vars.innodb_data_pending_fsyncs = fil_n_pending_log_flushes + fil_n_pending_tablespace_flushes; export_vars.innodb_data_fsyncs = os_n_fsyncs; export_vars.innodb_data_read = srv_data_read; export_vars.innodb_data_reads = os_n_file_reads; export_vars.innodb_data_writes = os_n_file_writes; export_vars.innodb_data_written = srv_data_written; export_vars.innodb_buffer_pool_read_requests = buf_pool->n_page_gets; export_vars.innodb_buffer_pool_write_requests = srv_buf_pool_write_requests; export_vars.innodb_buffer_pool_wait_free = srv_buf_pool_wait_free; export_vars.innodb_buffer_pool_pages_flushed = srv_buf_pool_flushed; export_vars.innodb_buffer_pool_reads = srv_buf_pool_reads; export_vars.innodb_buffer_pool_read_ahead_rnd = srv_read_ahead_rnd; export_vars.innodb_buffer_pool_read_ahead_seq = srv_read_ahead_seq; export_vars.innodb_buffer_pool_pages_data = UT_LIST_GET_LEN(buf_pool->LRU); export_vars.innodb_buffer_pool_pages_dirty = UT_LIST_GET_LEN(buf_pool->flush_list); export_vars.innodb_buffer_pool_pages_free = UT_LIST_GET_LEN(buf_pool->free); export_vars.innodb_buffer_pool_pages_latched = buf_get_latched_pages_number(); export_vars.innodb_buffer_pool_pages_total = buf_pool->curr_size; export_vars.innodb_buffer_pool_pages_misc = buf_pool->max_size - UT_LIST_GET_LEN(buf_pool->LRU) - UT_LIST_GET_LEN(buf_pool->free); export_vars.innodb_page_size = UNIV_PAGE_SIZE; export_vars.innodb_log_waits = srv_log_waits; export_vars.innodb_os_log_written = srv_os_log_written; export_vars.innodb_os_log_fsyncs = fil_n_log_flushes; export_vars.innodb_os_log_pending_fsyncs = fil_n_pending_log_flushes; export_vars.innodb_os_log_pending_writes = srv_os_log_pending_writes; export_vars.innodb_log_write_requests = srv_log_write_requests; export_vars.innodb_log_writes = srv_log_writes; export_vars.innodb_dblwr_pages_written = srv_dblwr_pages_written; export_vars.innodb_dblwr_writes = srv_dblwr_writes; export_vars.innodb_pages_created = buf_pool->n_pages_created; export_vars.innodb_pages_read = buf_pool->n_pages_read; export_vars.innodb_pages_written = buf_pool->n_pages_written; export_vars.innodb_row_lock_waits = srv_n_lock_wait_count; export_vars.innodb_row_lock_current_waits = srv_n_lock_wait_current_count; export_vars.innodb_row_lock_time = srv_n_lock_wait_time / 1000; if (srv_n_lock_wait_count > 0) { export_vars.innodb_row_lock_time_avg = (ulint) (srv_n_lock_wait_time / 1000 / srv_n_lock_wait_count); } else { export_vars.innodb_row_lock_time_avg = 0; } export_vars.innodb_row_lock_time_max = srv_n_lock_max_wait_time / 1000; export_vars.innodb_rows_read = srv_n_rows_read; export_vars.innodb_rows_inserted = srv_n_rows_inserted; export_vars.innodb_rows_updated = srv_n_rows_updated; export_vars.innodb_rows_deleted = srv_n_rows_deleted; mutex_exit(&srv_innodb_monitor_mutex); } /************************************************************************* A thread which wakes up threads whose lock wait may have lasted too long. This also prints the info output by various InnoDB monitors. */ os_thread_ret_t srv_lock_timeout_and_monitor_thread( /*================================*/ /* out: a dummy parameter */ void* arg __attribute__((unused))) /* in: a dummy parameter required by os_thread_create */ { srv_slot_t* slot; double time_elapsed; time_t current_time; time_t last_table_monitor_time; time_t last_tablespace_monitor_time; time_t last_monitor_time; ibool some_waits; double wait_time; ulint i; #ifdef UNIV_DEBUG_THREAD_CREATION fprintf(stderr, "Lock timeout thread starts, id %lu\n", os_thread_pf(os_thread_get_curr_id())); #endif UT_NOT_USED(arg); srv_last_monitor_time = time(NULL); last_table_monitor_time = time(NULL); last_tablespace_monitor_time = time(NULL); last_monitor_time = time(NULL); loop: srv_lock_timeout_and_monitor_active = TRUE; /* When someone is waiting for a lock, we wake up every second and check if a timeout has passed for a lock wait */ os_thread_sleep(1000000); /* In case mutex_exit is not a memory barrier, it is theoretically possible some threads are left waiting though the semaphore is already released. Wake up those threads: */ sync_arr_wake_threads_if_sema_free(); current_time = time(NULL); time_elapsed = difftime(current_time, last_monitor_time); if (time_elapsed > 15) { last_monitor_time = time(NULL); if (srv_print_innodb_monitor) { srv_printf_innodb_monitor(stderr, NULL, NULL); } if (srv_innodb_status) { mutex_enter(&srv_monitor_file_mutex); rewind(srv_monitor_file); srv_printf_innodb_monitor(srv_monitor_file, NULL, NULL); os_file_set_eof(srv_monitor_file); mutex_exit(&srv_monitor_file_mutex); } if (srv_print_innodb_tablespace_monitor && difftime(current_time, last_tablespace_monitor_time) > 60) { last_tablespace_monitor_time = time(NULL); fputs("========================" "========================\n", stderr); ut_print_timestamp(stderr); fputs(" INNODB TABLESPACE MONITOR OUTPUT\n" "========================" "========================\n", stderr); fsp_print(0); fputs("Validating tablespace\n", stderr); fsp_validate(0); fputs("Validation ok\n" "---------------------------------------\n" "END OF INNODB TABLESPACE MONITOR OUTPUT\n" "=======================================\n", stderr); } if (srv_print_innodb_table_monitor && difftime(current_time, last_table_monitor_time) > 60) { last_table_monitor_time = time(NULL); fputs("===========================================\n", stderr); ut_print_timestamp(stderr); fputs(" INNODB TABLE MONITOR OUTPUT\n" "===========================================\n", stderr); dict_print(); fputs("-----------------------------------\n" "END OF INNODB TABLE MONITOR OUTPUT\n" "==================================\n", stderr); } } mutex_enter(&kernel_mutex); some_waits = FALSE; /* Check of all slots if a thread is waiting there, and if it has exceeded the time limit */ for (i = 0; i < OS_THREAD_MAX_N; i++) { slot = srv_mysql_table + i; if (slot->in_use) { some_waits = TRUE; wait_time = ut_difftime(ut_time(), slot->suspend_time); if (srv_lock_wait_timeout < 100000000 && (wait_time > (double) srv_lock_wait_timeout || wait_time < 0)) { /* Timeout exceeded or a wrap-around in system time counter: cancel the lock request queued by the transaction and release possible other transactions waiting behind; it is possible that the lock has already been granted: in that case do nothing */ if (thr_get_trx(slot->thr)->wait_lock) { lock_cancel_waiting_and_release( thr_get_trx(slot->thr) ->wait_lock); } } } } os_event_reset(srv_lock_timeout_thread_event); mutex_exit(&kernel_mutex); if (srv_shutdown_state >= SRV_SHUTDOWN_CLEANUP) { goto exit_func; } if (some_waits || srv_print_innodb_monitor || srv_print_innodb_lock_monitor || srv_print_innodb_tablespace_monitor || srv_print_innodb_table_monitor) { goto loop; } /* No one was waiting for a lock and no monitor was active: suspend this thread */ srv_lock_timeout_and_monitor_active = FALSE; #if 0 /* The following synchronisation is disabled, since the InnoDB monitor output is to be updated every 15 seconds. */ os_event_wait(srv_lock_timeout_thread_event); #endif goto loop; exit_func: srv_lock_timeout_and_monitor_active = FALSE; /* We count the number of threads in os_thread_exit(). A created thread should always use that to exit and not use return() to exit. */ os_thread_exit(NULL); OS_THREAD_DUMMY_RETURN; } /************************************************************************* A thread which prints warnings about semaphore waits which have lasted too long. These can be used to track bugs which cause hangs. */ os_thread_ret_t srv_error_monitor_thread( /*=====================*/ /* out: a dummy parameter */ void* arg __attribute__((unused))) /* in: a dummy parameter required by os_thread_create */ { /* number of successive fatal timeouts observed */ ulint fatal_cnt = 0; dulint old_lsn; dulint new_lsn; old_lsn = srv_start_lsn; #ifdef UNIV_DEBUG_THREAD_CREATION fprintf(stderr, "Error monitor thread starts, id %lu\n", os_thread_pf(os_thread_get_curr_id())); #endif loop: srv_error_monitor_active = TRUE; /* Try to track a strange bug reported by Harald Fuchs and others, where the lsn seems to decrease at times */ new_lsn = log_get_lsn(); if (ut_dulint_cmp(new_lsn, old_lsn) < 0) { ut_print_timestamp(stderr); fprintf(stderr, " InnoDB: Error: old log sequence number %lu %lu" " was greater\n" "InnoDB: than the new log sequence number %lu %lu!\n" "InnoDB: Please submit a bug report" " to http://bugs.mysql.com\n", (ulong) ut_dulint_get_high(old_lsn), (ulong) ut_dulint_get_low(old_lsn), (ulong) ut_dulint_get_high(new_lsn), (ulong) ut_dulint_get_low(new_lsn)); } old_lsn = new_lsn; if (difftime(time(NULL), srv_last_monitor_time) > 60) { /* We referesh InnoDB Monitor values so that averages are printed from at most 60 last seconds */ srv_refresh_innodb_monitor_stats(); } if (sync_array_print_long_waits()) { fatal_cnt++; if (fatal_cnt > 5) { fprintf(stderr, "InnoDB: Error: semaphore wait has lasted" " > %lu seconds\n" "InnoDB: We intentionally crash the server," " because it appears to be hung.\n", (ulong) srv_fatal_semaphore_wait_threshold); ut_error; } } else { fatal_cnt = 0; } /* Flush stderr so that a database user gets the output to possible MySQL error file */ fflush(stderr); os_thread_sleep(2000000); if (srv_shutdown_state < SRV_SHUTDOWN_CLEANUP) { goto loop; } srv_error_monitor_active = FALSE; /* We count the number of threads in os_thread_exit(). A created thread should always use that to exit and not use return() to exit. */ os_thread_exit(NULL); OS_THREAD_DUMMY_RETURN; } /*********************************************************************** Tells the InnoDB server that there has been activity in the database and wakes up the master thread if it is suspended (not sleeping). Used in the MySQL interface. Note that there is a small chance that the master thread stays suspended (we do not protect our operation with the kernel mutex, for performace reasons). */ void srv_active_wake_master_thread(void) /*===============================*/ { srv_activity_count++; if (srv_n_threads_active[SRV_MASTER] == 0) { mutex_enter(&kernel_mutex); srv_release_threads(SRV_MASTER, 1); mutex_exit(&kernel_mutex); } } /*********************************************************************** Wakes up the master thread if it is suspended or being suspended. */ void srv_wake_master_thread(void) /*========================*/ { srv_activity_count++; mutex_enter(&kernel_mutex); srv_release_threads(SRV_MASTER, 1); mutex_exit(&kernel_mutex); } /************************************************************************* The master thread controlling the server. */ os_thread_ret_t srv_master_thread( /*==============*/ /* out: a dummy parameter */ void* arg __attribute__((unused))) /* in: a dummy parameter required by os_thread_create */ { os_event_t event; time_t last_flush_time; time_t current_time; ulint old_activity_count; ulint n_pages_purged; ulint n_bytes_merged; ulint n_pages_flushed; ulint n_bytes_archived; ulint n_tables_to_drop; ulint n_ios; ulint n_ios_old; ulint n_ios_very_old; ulint n_pend_ios; ibool skip_sleep = FALSE; ulint i; #ifdef UNIV_DEBUG_THREAD_CREATION fprintf(stderr, "Master thread starts, id %lu\n", os_thread_pf(os_thread_get_curr_id())); #endif srv_main_thread_process_no = os_proc_get_number(); srv_main_thread_id = os_thread_pf(os_thread_get_curr_id()); srv_table_reserve_slot(SRV_MASTER); mutex_enter(&kernel_mutex); srv_n_threads_active[SRV_MASTER]++; mutex_exit(&kernel_mutex); loop: /*****************************************************************/ /* ---- When there is database activity by users, we cycle in this loop */ srv_main_thread_op_info = "reserving kernel mutex"; n_ios_very_old = log_sys->n_log_ios + buf_pool->n_pages_read + buf_pool->n_pages_written; mutex_enter(&kernel_mutex); /* Store the user activity counter at the start of this loop */ old_activity_count = srv_activity_count; mutex_exit(&kernel_mutex); if (srv_force_recovery >= SRV_FORCE_NO_BACKGROUND) { goto suspend_thread; } /* ---- We run the following loop approximately once per second when there is database activity */ skip_sleep = FALSE; for (i = 0; i < 10; i++) { n_ios_old = log_sys->n_log_ios + buf_pool->n_pages_read + buf_pool->n_pages_written; srv_main_thread_op_info = "sleeping"; if (!skip_sleep) { os_thread_sleep(1000000); } skip_sleep = FALSE; /* ALTER TABLE in MySQL requires on Unix that the table handler can drop tables lazily after there no longer are SELECT queries to them. */ srv_main_thread_op_info = "doing background drop tables"; row_drop_tables_for_mysql_in_background(); srv_main_thread_op_info = ""; if (srv_fast_shutdown && srv_shutdown_state > 0) { goto background_loop; } /* We flush the log once in a second even if no commit is issued or the we have specified in my.cnf no flush at transaction commit */ srv_main_thread_op_info = "flushing log"; log_buffer_flush_to_disk(); srv_main_thread_op_info = "making checkpoint"; log_free_check(); /* If there were less than 5 i/os during the one second sleep, we assume that there is free disk i/o capacity available, and it makes sense to do an insert buffer merge. */ n_pend_ios = buf_get_n_pending_ios() + log_sys->n_pending_writes; n_ios = log_sys->n_log_ios + buf_pool->n_pages_read + buf_pool->n_pages_written; if (n_pend_ios < 3 && (n_ios - n_ios_old < 5)) { srv_main_thread_op_info = "doing insert buffer merge"; ibuf_contract_for_n_pages( TRUE, srv_insert_buffer_batch_size / 4); srv_main_thread_op_info = "flushing log"; log_buffer_flush_to_disk(); } if (UNIV_UNLIKELY(buf_get_modified_ratio_pct() > srv_max_buf_pool_modified_pct)) { /* Try to keep the number of modified pages in the buffer pool under the limit wished by the user */ n_pages_flushed = buf_flush_batch(BUF_FLUSH_LIST, 100, ut_dulint_max); /* If we had to do the flush, it may have taken even more than 1 second, and also, there may be more to flush. Do not sleep 1 second during the next iteration of this loop. */ skip_sleep = TRUE; } if (srv_activity_count == old_activity_count) { /* There is no user activity at the moment, go to the background loop */ goto background_loop; } } /* ---- We perform the following code approximately once per 10 seconds when there is database activity */ #ifdef MEM_PERIODIC_CHECK /* Check magic numbers of every allocated mem block once in 10 seconds */ mem_validate_all_blocks(); #endif /* If there were less than 200 i/os during the 10 second period, we assume that there is free disk i/o capacity available, and it makes sense to flush 100 pages. */ n_pend_ios = buf_get_n_pending_ios() + log_sys->n_pending_writes; n_ios = log_sys->n_log_ios + buf_pool->n_pages_read + buf_pool->n_pages_written; if (n_pend_ios < 3 && (n_ios - n_ios_very_old < 200)) { srv_main_thread_op_info = "flushing buffer pool pages"; buf_flush_batch(BUF_FLUSH_LIST, 100, ut_dulint_max); srv_main_thread_op_info = "flushing log"; log_buffer_flush_to_disk(); } /* We run a batch of insert buffer merge every 10 seconds, even if the server were active */ srv_main_thread_op_info = "doing insert buffer merge"; ibuf_contract_for_n_pages(TRUE, srv_insert_buffer_batch_size / 4); srv_main_thread_op_info = "flushing log"; log_buffer_flush_to_disk(); /* We run a full purge every 10 seconds, even if the server were active */ n_pages_purged = 1; last_flush_time = time(NULL); while (n_pages_purged) { if (srv_fast_shutdown && srv_shutdown_state > 0) { goto background_loop; } srv_main_thread_op_info = "purging"; n_pages_purged = trx_purge(); current_time = time(NULL); if (difftime(current_time, last_flush_time) > 1) { srv_main_thread_op_info = "flushing log"; log_buffer_flush_to_disk(); last_flush_time = current_time; } } srv_main_thread_op_info = "flushing buffer pool pages"; /* Flush a few oldest pages to make a new checkpoint younger */ if (buf_get_modified_ratio_pct() > 70) { /* If there are lots of modified pages in the buffer pool (> 70 %), we assume we can afford reserving the disk(s) for the time it requires to flush 100 pages */ n_pages_flushed = buf_flush_batch(BUF_FLUSH_LIST, 100, ut_dulint_max); } else { /* Otherwise, we only flush a small number of pages so that we do not unnecessarily use much disk i/o capacity from other work */ n_pages_flushed = buf_flush_batch(BUF_FLUSH_LIST, 10, ut_dulint_max); } srv_main_thread_op_info = "making checkpoint"; /* Make a new checkpoint about once in 10 seconds */ log_checkpoint(TRUE, FALSE); srv_main_thread_op_info = "reserving kernel mutex"; mutex_enter(&kernel_mutex); /* ---- When there is database activity, we jump from here back to the start of loop */ if (srv_activity_count != old_activity_count) { mutex_exit(&kernel_mutex); goto loop; } mutex_exit(&kernel_mutex); /* If the database is quiet, we enter the background loop */ /*****************************************************************/ background_loop: /* ---- In this loop we run background operations when the server is quiet from user activity. Also in the case of a shutdown, we loop here, flushing the buffer pool to the data files. */ /* The server has been quiet for a while: start running background operations */ srv_main_thread_op_info = "doing background drop tables"; n_tables_to_drop = row_drop_tables_for_mysql_in_background(); if (n_tables_to_drop > 0) { /* Do not monopolize the CPU even if there are tables waiting in the background drop queue. (It is essentially a bug if MySQL tries to drop a table while there are still open handles to it and we had to put it to the background drop queue.) */ os_thread_sleep(100000); } srv_main_thread_op_info = "purging"; /* Run a full purge */ n_pages_purged = 1; last_flush_time = time(NULL); while (n_pages_purged) { if (srv_fast_shutdown && srv_shutdown_state > 0) { break; } srv_main_thread_op_info = "purging"; n_pages_purged = trx_purge(); current_time = time(NULL); if (difftime(current_time, last_flush_time) > 1) { srv_main_thread_op_info = "flushing log"; log_buffer_flush_to_disk(); last_flush_time = current_time; } } srv_main_thread_op_info = "reserving kernel mutex"; mutex_enter(&kernel_mutex); if (srv_activity_count != old_activity_count) { mutex_exit(&kernel_mutex); goto loop; } mutex_exit(&kernel_mutex); srv_main_thread_op_info = "doing insert buffer merge"; if (srv_fast_shutdown && srv_shutdown_state > 0) { n_bytes_merged = 0; } else { n_bytes_merged = ibuf_contract_for_n_pages( TRUE, srv_insert_buffer_batch_size); } srv_main_thread_op_info = "reserving kernel mutex"; mutex_enter(&kernel_mutex); if (srv_activity_count != old_activity_count) { mutex_exit(&kernel_mutex); goto loop; } mutex_exit(&kernel_mutex); flush_loop: srv_main_thread_op_info = "flushing buffer pool pages"; if (srv_fast_shutdown < 2) { n_pages_flushed = buf_flush_batch(BUF_FLUSH_LIST, 100, ut_dulint_max); } else { /* In the fastest shutdown we do not flush the buffer pool to data files: we set n_pages_flushed to 0 artificially. */ n_pages_flushed = 0; } srv_main_thread_op_info = "reserving kernel mutex"; mutex_enter(&kernel_mutex); if (srv_activity_count != old_activity_count) { mutex_exit(&kernel_mutex); goto loop; } mutex_exit(&kernel_mutex); srv_main_thread_op_info = "waiting for buffer pool flush to end"; buf_flush_wait_batch_end(BUF_FLUSH_LIST); srv_main_thread_op_info = "flushing log"; log_buffer_flush_to_disk(); srv_main_thread_op_info = "making checkpoint"; log_checkpoint(TRUE, FALSE); if (buf_get_modified_ratio_pct() > srv_max_buf_pool_modified_pct) { /* Try to keep the number of modified pages in the buffer pool under the limit wished by the user */ goto flush_loop; } srv_main_thread_op_info = "reserving kernel mutex"; mutex_enter(&kernel_mutex); if (srv_activity_count != old_activity_count) { mutex_exit(&kernel_mutex); goto loop; } mutex_exit(&kernel_mutex); /* srv_main_thread_op_info = "archiving log (if log archive is on)"; log_archive_do(FALSE, &n_bytes_archived); */ n_bytes_archived = 0; /* Keep looping in the background loop if still work to do */ if (srv_fast_shutdown && srv_shutdown_state > 0) { if (n_tables_to_drop + n_pages_flushed + n_bytes_archived != 0) { /* If we are doing a fast shutdown (= the default) we do not do purge or insert buffer merge. But we flush the buffer pool completely to disk. In a 'very fast' shutdown we do not flush the buffer pool to data files: we have set n_pages_flushed to 0 artificially. */ goto background_loop; } } else if (n_tables_to_drop + n_pages_purged + n_bytes_merged + n_pages_flushed + n_bytes_archived != 0) { /* In a 'slow' shutdown we run purge and the insert buffer merge to completion */ goto background_loop; } /* There is no work for background operations either: suspend master thread to wait for more server activity */ suspend_thread: srv_main_thread_op_info = "suspending"; mutex_enter(&kernel_mutex); if (row_get_background_drop_list_len_low() > 0) { mutex_exit(&kernel_mutex); goto loop; } event = srv_suspend_thread(); mutex_exit(&kernel_mutex); /* DO NOT CHANGE THIS STRING. innobase_start_or_create_for_mysql() waits for database activity to die down when converting < 4.1.x databases, and relies on this string being exactly as it is. InnoDB manual also mentions this string in several places. */ srv_main_thread_op_info = "waiting for server activity"; os_event_wait(event); if (srv_shutdown_state == SRV_SHUTDOWN_EXIT_THREADS) { /* This is only extra safety, the thread should exit already when the event wait ends */ os_thread_exit(NULL); } /* When there is user activity, InnoDB will set the event and the main thread goes back to loop. */ goto loop; OS_THREAD_DUMMY_RETURN; /* Not reached, avoid compiler warning */ } #endif /* !UNIV_HOTBACKUP */