diff options
Diffstat (limited to 'mysys/thr_lock.c')
| -rw-r--r-- | mysys/thr_lock.c | 1837 |
1 files changed, 1837 insertions, 0 deletions
diff --git a/mysys/thr_lock.c b/mysys/thr_lock.c new file mode 100644 index 00000000..168ec035 --- /dev/null +++ b/mysys/thr_lock.c @@ -0,0 +1,1837 @@ +/* Copyright (c) 2000, 2011, Oracle and/or its affiliates. + Copyright (c) 2012, Monty Program Ab. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */ + +/* +Read and write locks for Posix threads. All tread must acquire +all locks it needs through thr_multi_lock() to avoid dead-locks. +A lock consists of a master lock (THR_LOCK), and lock instances +(THR_LOCK_DATA). +Any thread can have any number of lock instances (read and write:s) on +any lock. All lock instances must be freed. +Locks are prioritized according to: + +The current lock types are: + +TL_READ # Low priority read +TL_READ_WITH_SHARED_LOCKS +TL_READ_HIGH_PRIORITY # High priority read +TL_READ_NO_INSERT # Read without concurrent inserts +TL_WRITE_ALLOW_WRITE # Write lock that allows other writers +TL_WRITE_CONCURRENT_INSERT + # Insert that can be mixed when selects +TL_WRITE_DELAYED # Used by delayed insert + # Allows lower locks to take over +TL_WRITE_LOW_PRIORITY # Low priority write +TL_WRITE # High priority write +TL_WRITE_ONLY # High priority write + # Abort all new lock request with an error + +Locks are prioritized according to: + +WRITE_ALLOW_WRITE, WRITE_CONCURRENT_INSERT, WRITE_DELAYED, +WRITE_LOW_PRIORITY, READ, WRITE, READ_HIGH_PRIORITY and WRITE_ONLY + +Locks in the same privilege level are scheduled in first-in-first-out order. + +To allow concurrent read/writes locks, with 'WRITE_CONCURRENT_INSERT' one +should put a pointer to the following functions in the lock structure: +(If the pointer is zero (default), the function is not called) + +check_status: + Before giving a lock of type TL_WRITE_CONCURRENT_INSERT, + we check if this function exists and returns 0. + If not, then the lock is upgraded to TL_WRITE_LOCK + In MyISAM this is a simple check if the insert can be done + at the end of the datafile. +update_status: + in thr_reschedule_write_lock(), when an insert delayed thread + downgrades TL_WRITE lock to TL_WRITE_DELAYED, to allow SELECT + threads to proceed. + A storage engine should also call update_status internally + in the ::external_lock(F_UNLCK) method. + In MyISAM and CSV this functions updates the length of the datafile. + MySQL does in some exceptional cases (when doing DLL statements on + open tables calls thr_unlock() followed by thr_lock() without calling + ::external_lock() in between. In this case thr_unlock() is called with + the THR_UNLOCK_UPDATE_STATUS flag and thr_unlock() will call + update_status for write locks. +get_status: + When one gets a lock this functions is called. + In MyISAM this stores the number of rows and size of the datafile + for concurrent reads. + +The lock algorithm allows one to have one TL_WRITE_CONCURRENT_INSERT or +one TL_WRITE_DELAYED lock at the same time as multiple read locks. + +In addition, if lock->allow_multiple_concurrent_insert is set then there can +be any number of TL_WRITE_CONCURRENT_INSERT locks aktive at the same time. +*/ + +#if !defined(MAIN) && !defined(DBUG_OFF) && !defined(EXTRA_DEBUG) +#define FORCE_DBUG_OFF +#endif + +#include "mysys_priv.h" + +#include "thr_lock.h" +#include "mysql/psi/mysql_table.h" +#include <m_string.h> +#include <errno.h> + +my_bool thr_lock_inited=0; +ulong locks_immediate = 0L, locks_waited = 0L; +enum thr_lock_type thr_upgraded_concurrent_insert_lock = TL_WRITE; + +/* The following constants are only for debug output */ +#define MAX_THREADS 1000 +#define MAX_LOCKS 1000 + + +LIST *thr_lock_thread_list; /* List of threads in use */ +ulong max_write_lock_count= ~(ulong) 0L; + +static void (*before_lock_wait)(void)= 0; +static void (*after_lock_wait)(void)= 0; + +void thr_set_lock_wait_callback(void (*before_wait)(void), + void (*after_wait)(void)) +{ + before_lock_wait= before_wait; + after_lock_wait= after_wait; +} + +static inline mysql_cond_t *get_cond(void) +{ + return &my_thread_var->suspend; +} + + +/* + Sort locks in priority order + + LOCK_CMP() + A First lock + B Second lock + + Return: + 0 if A >= B + 1 if A < B + + Priority for locks (decides in which order locks are locked) + We want all write locks to be first, followed by read locks. + Locks from MERGE tables has a little lower priority than other + locks, to allow one to release merge tables without having + to unlock and re-lock other locks. + The lower the number, the higher the priority for the lock. + For MERGE tables we add 2 (THR_LOCK_MERGE_PRIV) to the lock priority. + THR_LOCK_LATE_PRIV (1) is used when one locks other tables to be merged + with existing locks. This way we prioritize the original locks over the + new locks. +*/ + + +static inline int LOCK_CMP(THR_LOCK_DATA *a, THR_LOCK_DATA *b) +{ + if (a->lock != b->lock) + return a->lock < b->lock; + + if (a->type != b->type) + return a->type > b->type; + + return a->priority < b->priority; +} + + +/* + For the future (now the thread specific cond is alloced by my_pthread.c) +*/ + +my_bool init_thr_lock() +{ + thr_lock_inited=1; + return 0; +} + +static inline my_bool +thr_lock_owner_equal(THR_LOCK_INFO *rhs, THR_LOCK_INFO *lhs) +{ + return rhs == lhs; +} + + +#ifdef EXTRA_DEBUG +#define MAX_FOUND_ERRORS 10 /* Report 10 first errors */ +static uint found_errors=0; + +static int check_lock(struct st_lock_list *list, const char* lock_type, + const char *where, my_bool same_owner, my_bool no_cond, + my_bool read_lock) +{ + THR_LOCK_DATA *data,**prev; + uint count=0; + + prev= &list->data; + if (list->data) + { + enum thr_lock_type last_lock_type= list->data->type; + THR_LOCK_INFO *first_owner= list->data->owner; + + for (data=list->data; data && count++ < MAX_LOCKS ; data=data->next) + { + if (data->type == TL_UNLOCK) + { + fprintf(stderr, + "Warning: Found unlocked lock at %s: %s\n", + lock_type, where); + return 1; + } + if ((read_lock && data->type > TL_READ_NO_INSERT) || + (!read_lock && data->type <= TL_READ_NO_INSERT)) + { + fprintf(stderr, + "Warning: Found %s lock in %s queue at %s: %s\n", + read_lock ? "write" : "read", + read_lock ? "read" : "write", + lock_type, where); + return 1; + } + if (data->type != last_lock_type) + last_lock_type=TL_IGNORE; + if (data->prev != prev) + { + fprintf(stderr, + "Warning: prev link %d didn't point at previous lock at %s: %s\n", + count, lock_type, where); + return 1; + } + if (same_owner && + !thr_lock_owner_equal(data->owner, first_owner) && + last_lock_type != TL_WRITE_ALLOW_WRITE && + last_lock_type != TL_WRITE_CONCURRENT_INSERT) + { + fprintf(stderr, + "Warning: Found locks from different threads for lock '%s' in '%s' at '%s'. org_lock_type: %d last_lock_type: %d new_lock_type: %d\n", + data->lock->name ? data->lock->name : "", + lock_type, where, list->data->type, last_lock_type, + data->type); + return 1; + } + if (no_cond && data->cond) + { + fprintf(stderr, + "Warning: Found active lock with not reset cond %s: %s\n", + lock_type,where); + return 1; + } + prev= &data->next; + } + if (data) + { + fprintf(stderr,"Warning: found too many locks at %s: %s\n", + lock_type,where); + return 1; + } + } + if (prev != list->last) + { + fprintf(stderr,"Warning: last didn't point at last lock at %s: %s\n", + lock_type, where); + return 1; + } + return 0; +} + + +static void check_locks(THR_LOCK *lock, const char *where, + enum thr_lock_type type, + my_bool allow_no_locks) +{ + uint old_found_errors=found_errors; + DBUG_ENTER("check_locks"); + + if (found_errors < MAX_FOUND_ERRORS) + { + if (check_lock(&lock->write,"write",where,1,1,0) | + check_lock(&lock->write_wait,"write_wait",where,0,0,0) | + check_lock(&lock->read,"read",where,0,1,1) | + check_lock(&lock->read_wait,"read_wait",where,0,0,1)) + { + DBUG_ASSERT(my_assert_on_error == 0); + found_errors++; + } + + if (found_errors < MAX_FOUND_ERRORS) + { + uint count=0, count2= 0; + THR_LOCK_DATA *data; + for (data=lock->read.data ; data ; data=data->next) + { + count2++; + if (data->type == TL_READ_NO_INSERT) + count++; + /* Protect against infinite loop. */ + DBUG_ASSERT(count <= lock->read_no_write_count && + count2 <= MAX_LOCKS); + } + if (count != lock->read_no_write_count) + { + found_errors++; + fprintf(stderr, + "Warning at '%s': Locks read_no_write_count was %u when it should have been %u\n", where, lock->read_no_write_count,count); + } + + if (!lock->write.data) + { + if (!allow_no_locks && !lock->read.data && + (lock->write_wait.data || lock->read_wait.data)) + { + found_errors++; + fprintf(stderr, + "Warning at '%s': No locks in use but locks are in wait queue\n", + where); + } + if (!lock->write_wait.data) + { + if (!allow_no_locks && lock->read_wait.data) + { + found_errors++; + fprintf(stderr, + "Warning at '%s': No write locks and waiting read locks\n", + where); + } + } + else + { + if (!allow_no_locks && + (((lock->write_wait.data->type == TL_WRITE_CONCURRENT_INSERT || + lock->write_wait.data->type == TL_WRITE_ALLOW_WRITE) && + !lock->read_no_write_count) || + (lock->write_wait.data->type == TL_WRITE_DELAYED && + !lock->read.data))) + { + found_errors++; + fprintf(stderr, + "Warning at '%s': Write lock %d waiting while no exclusive read locks\n",where,(int) lock->write_wait.data->type); + DBUG_PRINT("warning", ("Warning at '%s': Write lock %d waiting while no exclusive read locks",where,(int) lock->write_wait.data->type)); + } + } + } + else + { + /* We have at least one write lock */ + if (lock->write.data->type == TL_WRITE_CONCURRENT_INSERT) + { + count= 0; + for (data=lock->write.data->next; + data && count < MAX_LOCKS; + data=data->next) + { + if (data->type != TL_WRITE_CONCURRENT_INSERT && + data->type != TL_WRITE_ALLOW_WRITE) + { + fprintf(stderr, + "Warning at '%s': Found TL_WRITE_CONCURRENT_INSERT lock mixed with other write lock: %d\n", + where, data->type); + DBUG_PRINT("warning", ("Warning at '%s': Found TL_WRITE_CONCURRENT_INSERT lock mixed with other write lock: %d", + where, data->type)); + break; + } + } + } + if (lock->write_wait.data) + { + if (!allow_no_locks && + lock->write.data->type == TL_WRITE_ALLOW_WRITE && + lock->write_wait.data->type == TL_WRITE_ALLOW_WRITE) + { + found_errors++; + fprintf(stderr, + "Warning at '%s': Found WRITE_ALLOW_WRITE lock waiting for WRITE_ALLOW_WRITE lock\n", + where); + DBUG_PRINT("warning", ("Warning at '%s': Found WRITE_ALLOW_WRITE lock waiting for WRITE_ALLOW_WRITE lock", + where)); + + } + } + if (lock->read.data) + { + for (data=lock->read.data ; data ; data=data->next) + { + if (!thr_lock_owner_equal(lock->write.data->owner, + data->owner) && + ((lock->write.data->type > TL_WRITE_DELAYED && + lock->write.data->type != TL_WRITE_ONLY) || + ((lock->write.data->type == TL_WRITE_CONCURRENT_INSERT || + lock->write.data->type == TL_WRITE_ALLOW_WRITE) && + data->type == TL_READ_NO_INSERT))) + { + found_errors++; + fprintf(stderr, + "Warning at '%s' for lock: %d: Found lock of type %d that is write and read locked. Read_no_write_count: %d\n", + where, (int) type, lock->write.data->type, + lock->read_no_write_count); + DBUG_PRINT("warning",("At '%s' for lock %d: Found lock of type %d that is write and read locked", + where, (int) type, + lock->write.data->type)); + } + } + } + if (lock->read_wait.data) + { + if (!allow_no_locks && lock->write.data->type <= TL_WRITE_DELAYED && + lock->read_wait.data->type <= TL_READ_HIGH_PRIORITY) + { + found_errors++; + fprintf(stderr, + "Warning at '%s': Found read lock of type %d waiting for write lock of type %d\n", + where, + (int) lock->read_wait.data->type, + (int) lock->write.data->type); + } + } + } + } + if (found_errors != old_found_errors) + { + DBUG_PRINT("error",("Found wrong lock")); + } + } + DBUG_VOID_RETURN; +} + +#else /* EXTRA_DEBUG */ +#define check_locks(A,B,C,D) +#endif + + + /* Initialize a lock */ + +void thr_lock_init(THR_LOCK *lock) +{ + DBUG_ENTER("thr_lock_init"); + bzero((char*) lock,sizeof(*lock)); + mysql_mutex_init(key_THR_LOCK_mutex, &lock->mutex, MY_MUTEX_INIT_FAST); + lock->read.last= &lock->read.data; + lock->read_wait.last= &lock->read_wait.data; + lock->write_wait.last= &lock->write_wait.data; + lock->write.last= &lock->write.data; + + mysql_mutex_lock(&THR_LOCK_lock); /* Add to locks in use */ + lock->list.data=(void*) lock; + thr_lock_thread_list=list_add(thr_lock_thread_list,&lock->list); + mysql_mutex_unlock(&THR_LOCK_lock); + DBUG_VOID_RETURN; +} + + +void thr_lock_delete(THR_LOCK *lock) +{ + DBUG_ENTER("thr_lock_delete"); + mysql_mutex_lock(&THR_LOCK_lock); + thr_lock_thread_list=list_delete(thr_lock_thread_list,&lock->list); + mysql_mutex_unlock(&THR_LOCK_lock); + mysql_mutex_destroy(&lock->mutex); + DBUG_VOID_RETURN; +} + + +void thr_lock_info_init(THR_LOCK_INFO *info, struct st_my_thread_var *tmp) +{ + if (!tmp) + tmp= my_thread_var; + info->thread= tmp->pthread_self; + info->thread_id= tmp->id; +} + + /* Initialize a lock instance */ + +void thr_lock_data_init(THR_LOCK *lock,THR_LOCK_DATA *data, void *param) +{ + data->lock=lock; + data->type=TL_UNLOCK; + data->owner= 0; /* no owner yet */ + data->status_param=param; + data->cond=0; + data->priority= 0; + data->debug_print_param= 0; +} + + +static inline my_bool +has_old_lock(THR_LOCK_DATA *data, THR_LOCK_INFO *owner) +{ + for ( ; data ; data=data->next) + { + if (thr_lock_owner_equal(data->owner, owner)) + return 1; /* Already locked by thread */ + } + return 0; +} + +static void wake_up_waiters(THR_LOCK *lock); + + +static enum enum_thr_lock_result +wait_for_lock(struct st_lock_list *wait, THR_LOCK_DATA *data, + my_bool in_wait_list, ulong lock_wait_timeout) +{ + struct st_my_thread_var *thread_var= my_thread_var; + mysql_cond_t *cond= &thread_var->suspend; + struct timespec wait_timeout; + enum enum_thr_lock_result result= THR_LOCK_ABORTED; + PSI_stage_info old_stage; + my_bool use_wait_callbacks= FALSE; + DBUG_ENTER("wait_for_lock"); + + /* + One can use this to signal when a thread is going to wait for a lock. + See debug_sync.cc. + + Beware of waiting for a signal here. The lock has acquired its mutex. + While waiting on a signal here, the locking thread could not acquire + the mutex to release the lock. One could lock up the table + completely. + + In detail it works so: When thr_lock() tries to acquire a table + lock, it locks the lock->mutex, checks if it can have the lock, and + if not, it calls wait_for_lock(). Here it unlocks the table lock + while waiting on a condition. The sync point is located before this + wait for condition. If we have a waiting action here, we hold the + the table locks mutex all the time. Any attempt to look at the table + lock by another thread blocks it immediately on lock->mutex. This + can easily become an unexpected and unobvious blockage. So be + warned: Do not request a WAIT_FOR action for the 'wait_for_lock' + sync point unless you really know what you do. + */ + DEBUG_SYNC_C("wait_for_lock"); + + if (!in_wait_list) + { + (*wait->last)=data; /* Wait for lock */ + data->prev= wait->last; + wait->last= &data->next; + } + + statistic_increment(locks_waited, &THR_LOCK_lock); + + /* Set up control struct to allow others to abort locks */ + thread_var->current_mutex= &data->lock->mutex; + thread_var->current_cond= cond; + data->cond= cond; + + proc_info_hook(NULL, &stage_waiting_for_table_level_lock, + &old_stage, + __func__, __FILE__, __LINE__); + + /* + Since before_lock_wait potentially can create more threads to + scheduler work for, we don't want to call the before_lock_wait + callback unless it will really start to wait. + + For similar reasons, we do not want to call before_lock_wait and + after_lock_wait for each lap around the loop, so we restrict + ourselves to call it before_lock_wait once before starting to wait + and once after the thread has exited the wait loop. + */ + if ((!thread_var->abort || in_wait_list) && before_lock_wait) + { + use_wait_callbacks= TRUE; + (*before_lock_wait)(); + } + + set_timespec(wait_timeout, lock_wait_timeout); + while (!thread_var->abort || in_wait_list) + { + int rc= mysql_cond_timedwait(cond, &data->lock->mutex, &wait_timeout); + /* + We must break the wait if one of the following occurs: + - the connection has been aborted (!thread_var->abort), but + this is not a delayed insert thread (in_wait_list). For a delayed + insert thread the proper action at shutdown is, apparently, to + acquire the lock and complete the insert. + - the lock has been granted (data->cond is set to NULL by the granter), + or the waiting has been aborted (additionally data->type is set to + TL_UNLOCK). + - the wait has timed out (rc == ETIMEDOUT) + Order of checks below is important to not report about timeout + if the predicate is true. + */ + if (data->cond == 0) + { + DBUG_PRINT("thr_lock", ("lock granted/aborted")); + break; + } + if (rc == ETIMEDOUT || rc == ETIME) + { + /* purecov: begin inspected */ + DBUG_PRINT("thr_lock", ("lock timed out")); + result= THR_LOCK_WAIT_TIMEOUT; + break; + /* purecov: end */ + } + } + + /* + We call the after_lock_wait callback once the wait loop has + finished. + */ + if (after_lock_wait && use_wait_callbacks) + (*after_lock_wait)(); + + DBUG_PRINT("thr_lock", ("aborted: %d in_wait_list: %d", + thread_var->abort, in_wait_list)); + + if (data->cond || data->type == TL_UNLOCK) + { + if (data->cond) /* aborted or timed out */ + { + if (((*data->prev)=data->next)) /* remove from wait-list */ + data->next->prev= data->prev; + else + wait->last=data->prev; + data->type= TL_UNLOCK; /* No lock */ + check_locks(data->lock, "killed or timed out wait_for_lock", data->type, + 1); + wake_up_waiters(data->lock); + } + else + { + DBUG_PRINT("thr_lock", ("lock aborted")); + check_locks(data->lock, "aborted wait_for_lock", data->type, 0); + } + } + else + { + result= THR_LOCK_SUCCESS; + if (data->lock->get_status && + (*data->lock->get_status)(data->status_param, + data->type == TL_WRITE_CONCURRENT_INSERT)) + result= THR_LOCK_ABORTED; + check_locks(data->lock,"got wait_for_lock", data->type, 0); + } + mysql_mutex_unlock(&data->lock->mutex); + + /* The following must be done after unlock of lock->mutex */ + mysql_mutex_lock(&thread_var->mutex); + thread_var->current_mutex= 0; + thread_var->current_cond= 0; + mysql_mutex_unlock(&thread_var->mutex); + + proc_info_hook(NULL, &old_stage, NULL, __func__, __FILE__, __LINE__); + + DBUG_RETURN(result); +} + +static enum enum_thr_lock_result +thr_lock(THR_LOCK_DATA *data, THR_LOCK_INFO *owner, ulong lock_wait_timeout) +{ + THR_LOCK *lock=data->lock; + enum enum_thr_lock_result result= THR_LOCK_SUCCESS; + struct st_lock_list *wait_queue; + enum thr_lock_type lock_type= data->type; + MYSQL_TABLE_WAIT_VARIABLES(locker, state) /* no ';' */ + DBUG_ENTER("thr_lock"); + + data->next=0; + data->cond=0; /* safety */ + data->owner= owner; /* Must be reset ! */ + data->priority&= ~THR_LOCK_LATE_PRIV; + + MYSQL_START_TABLE_LOCK_WAIT(locker, &state, data->m_psi, + PSI_TABLE_LOCK, lock_type); + + mysql_mutex_lock(&lock->mutex); + DBUG_PRINT("lock",("data:%p thread:%lu lock:%p type: %d", + data, (ulong) data->owner->thread_id, + lock, (int) lock_type)); + check_locks(lock,(uint) lock_type <= (uint) TL_READ_NO_INSERT ? + "enter read_lock" : "enter write_lock", lock_type, 0); + if ((int) lock_type <= (int) TL_READ_NO_INSERT) + { + /* Request for READ lock */ + if (lock->write.data) + { + /* + We can allow a read lock even if there is already a + write lock on the table if they are owned by the same + thread or if they satisfy the following lock + compatibility matrix: + + Request + /------- + H|++++ WRITE_ALLOW_WRITE + e|+++- WRITE_CONCURRENT_INSERT + l|++++ WRITE_DELAYED + d |||| + |||\= READ_NO_INSERT + ||\ = READ_HIGH_PRIORITY + |\ = READ_WITH_SHARED_LOCKS + \ = READ + + + + = Request can be satisfied. + - = Request cannot be satisfied. + + READ_NO_INSERT and WRITE_ALLOW_WRITE should in principle + be incompatible. However this will cause starvation of + LOCK TABLE READ in InnoDB under high write load. + See Bug#42147 for more information. + */ + + DBUG_PRINT("lock",("write locked 1 by thread:%lu", + (ulong) lock->write.data->owner->thread_id)); + if (thr_lock_owner_equal(data->owner, lock->write.data->owner) || + (lock->write.data->type <= TL_WRITE_DELAYED && + (((int) lock_type <= (int) TL_READ_HIGH_PRIORITY) || + (lock->write.data->type != TL_WRITE_CONCURRENT_INSERT)))) + { /* Already got a write lock */ + (*lock->read.last)=data; /* Add to running FIFO */ + data->prev=lock->read.last; + lock->read.last= &data->next; + if (lock_type == TL_READ_NO_INSERT) + lock->read_no_write_count++; + check_locks(lock,"read lock with old write lock", lock_type, 0); + if ((lock->get_status) && (*lock->get_status)(data->status_param, 0)) + result= THR_LOCK_ABORTED; + statistic_increment(locks_immediate,&THR_LOCK_lock); + goto end; + } + if (lock->write.data->type == TL_WRITE_ONLY) + { + /* We are not allowed to get a READ lock in this case */ + data->type=TL_UNLOCK; + result= THR_LOCK_ABORTED; /* Can't wait for this one */ + goto end; + } + } + else if (!lock->write_wait.data || + lock->write_wait.data->type <= TL_WRITE_LOW_PRIORITY || + lock_type == TL_READ_HIGH_PRIORITY || + has_old_lock(lock->read.data, data->owner)) /* Has old read lock */ + { /* No important write-locks */ + (*lock->read.last)=data; /* Add to running FIFO */ + data->prev=lock->read.last; + lock->read.last= &data->next; + if (lock_type == TL_READ_NO_INSERT) + lock->read_no_write_count++; + check_locks(lock,"read lock with no write locks", lock_type, 0); + if ((lock->get_status) && (*lock->get_status)(data->status_param, 0)) + result= THR_LOCK_ABORTED; + statistic_increment(locks_immediate,&THR_LOCK_lock); + goto end; + } + /* + We're here if there is an active write lock or no write + lock but a high priority write waiting in the write_wait queue. + In the latter case we should yield the lock to the writer. + */ + wait_queue= &lock->read_wait; + } + else /* Request for WRITE lock */ + { + if (lock_type == TL_WRITE_DELAYED) + { + if (lock->write.data && lock->write.data->type == TL_WRITE_ONLY) + { + data->type=TL_UNLOCK; + result= THR_LOCK_ABORTED; /* Can't wait for this one */ + goto end; + } + if (lock->write.data || lock->read.data) + { + /* Add delayed write lock to write_wait queue, and return at once */ + (*lock->write_wait.last)=data; + data->prev=lock->write_wait.last; + lock->write_wait.last= &data->next; + data->cond=get_cond(); + /* + We don't have to do get_status here as we will do it when we change + the delayed lock to a real write lock + */ + statistic_increment(locks_immediate,&THR_LOCK_lock); + goto end; + } + } + else if (lock_type == TL_WRITE_CONCURRENT_INSERT && ! lock->check_status) + data->type=lock_type= thr_upgraded_concurrent_insert_lock; + + if (lock->write.data) /* If there is a write lock */ + { + if (lock->write.data->type == TL_WRITE_ONLY) + { + /* purecov: begin tested */ + /* Allow lock owner to bypass TL_WRITE_ONLY. */ + if (!thr_lock_owner_equal(data->owner, lock->write.data->owner)) + { + /* We are not allowed to get a lock in this case */ + data->type=TL_UNLOCK; + result= THR_LOCK_ABORTED; /* Can't wait for this one */ + goto end; + } + /* purecov: end */ + } + + /* + The idea is to allow us to get a lock at once if we already have + a write lock or if there is no pending write locks and if all + write locks are of the same type and are either + TL_WRITE_ALLOW_WRITE or TL_WRITE_CONCURRENT_INSERT and + there is no TL_READ_NO_INSERT lock. + + Note that, since lock requests for the same table are sorted in + such way that requests with higher thr_lock_type value come first + (with one exception (*)), lock being requested usually (**) has + equal or "weaker" type than one which thread might have already + acquired. + *) The only exception to this rule is case when type of old lock + is TL_WRITE_LOW_PRIORITY and type of new lock is changed inside + of thr_lock() from TL_WRITE_CONCURRENT_INSERT to TL_WRITE since + engine turns out to be not supporting concurrent inserts. + Note that since TL_WRITE has the same compatibility rules as + TL_WRITE_LOW_PRIORITY (their only difference is priority), + it is OK to grant new lock without additional checks in such + situation. + **) The exceptions are situations when: + - when old lock type is TL_WRITE_DELAYED + But these should never happen within MariaDB. + Therefore it is OK to allow acquiring write lock on the table if + this thread already holds some write lock on it. + + (INSERT INTO t1 VALUES (f1()), where f1() is stored function which + tries to update t1, is an example of statement which requests two + different types of write lock on the same table). + */ + DBUG_ASSERT(! has_old_lock(lock->write.data, data->owner) || + ((lock_type <= lock->write.data->type || + (lock_type == TL_WRITE && + lock->write.data->type == TL_WRITE_LOW_PRIORITY)) && + lock->write.data->type != TL_WRITE_DELAYED)); + + if (((lock_type == TL_WRITE_ALLOW_WRITE || + (lock_type == TL_WRITE_CONCURRENT_INSERT && + lock->allow_multiple_concurrent_insert && + !lock->read_no_write_count)) && + ! lock->write_wait.data && + lock->write.data->type == lock_type && + ! lock->read_no_write_count) || + has_old_lock(lock->write.data, data->owner)) + { + DBUG_PRINT("info", ("write_wait.data: %p old_type: %d", + lock->write_wait.data, + lock->write.data->type)); + + (*lock->write.last)=data; /* Add to running fifo */ + data->prev=lock->write.last; + lock->write.last= &data->next; + check_locks(lock,"second write lock", lock_type, 0); + if ((lock->get_status) && + (*lock->get_status)(data->status_param, + lock_type == TL_WRITE_CONCURRENT_INSERT)) + result= THR_LOCK_ABORTED; + statistic_increment(locks_immediate,&THR_LOCK_lock); + goto end; + } + DBUG_PRINT("lock",("write locked 2 by thread: %lu", + (ulong) lock->write.data->owner->thread_id)); + } + else + { + DBUG_PRINT("info", ("write_wait.data:%p", + lock->write_wait.data)); + if (!lock->write_wait.data) + { /* no scheduled write locks */ + my_bool concurrent_insert= 0; + if (lock_type == TL_WRITE_CONCURRENT_INSERT) + { + concurrent_insert= 1; + if ((*lock->check_status)(data->status_param)) + { + concurrent_insert= 0; + data->type=lock_type= thr_upgraded_concurrent_insert_lock; + } + } + + if (!lock->read.data || + (lock_type <= TL_WRITE_DELAYED && + ((lock_type != TL_WRITE_CONCURRENT_INSERT && + lock_type != TL_WRITE_ALLOW_WRITE) || + !lock->read_no_write_count))) + { + (*lock->write.last)=data; /* Add as current write lock */ + data->prev=lock->write.last; + lock->write.last= &data->next; + if ((lock->get_status) && + (*lock->get_status)(data->status_param, concurrent_insert)) + result= THR_LOCK_ABORTED; + check_locks(lock,"only write lock", lock_type, 0); + statistic_increment(locks_immediate,&THR_LOCK_lock); + goto end; + } + } + DBUG_PRINT("lock",("write locked 3 by thread:%lu type: %d", + (ulong) lock->read.data->owner->thread_id, + data->type)); + } + wait_queue= &lock->write_wait; + } + result= wait_for_lock(wait_queue, data, 0, lock_wait_timeout); + MYSQL_END_TABLE_LOCK_WAIT(locker); + DBUG_RETURN(result); +end: + mysql_mutex_unlock(&lock->mutex); + MYSQL_END_TABLE_LOCK_WAIT(locker); + DBUG_RETURN(result); +} + + +static inline void free_all_read_locks(THR_LOCK *lock, + my_bool using_concurrent_insert) +{ + THR_LOCK_DATA *data=lock->read_wait.data; + + check_locks(lock,"before freeing read locks", TL_UNLOCK, 1); + + /* move all locks from read_wait list to read list */ + (*lock->read.last)=data; + data->prev=lock->read.last; + lock->read.last=lock->read_wait.last; + + /* Clear read_wait list */ + lock->read_wait.last= &lock->read_wait.data; + + do + { + mysql_cond_t *cond= data->cond; + if ((int) data->type == (int) TL_READ_NO_INSERT) + { + if (using_concurrent_insert) + { + /* + We can't free this lock; + Link lock away from read chain back into read_wait chain + */ + if (((*data->prev)=data->next)) + data->next->prev=data->prev; + else + lock->read.last=data->prev; + *lock->read_wait.last= data; + data->prev= lock->read_wait.last; + lock->read_wait.last= &data->next; + continue; + } + lock->read_no_write_count++; + } + /* purecov: begin inspected */ + DBUG_PRINT("lock",("giving read lock to thread: %lu", + (ulong)data->owner->thread_id)); + /* purecov: end */ + data->cond=0; /* Mark thread free */ + mysql_cond_signal(cond); + } while ((data=data->next)); + *lock->read_wait.last=0; + if (!lock->read_wait.data) + lock->write_lock_count=0; + check_locks(lock,"after giving read locks", TL_UNLOCK, 0); +} + + /* Unlock lock and free next thread on same lock */ + +void thr_unlock(THR_LOCK_DATA *data, uint unlock_flags) +{ + THR_LOCK *lock=data->lock; + enum thr_lock_type lock_type=data->type; + DBUG_ENTER("thr_unlock"); + DBUG_PRINT("lock",("data: %p thread: %lu lock: %p", + data, (ulong) data->owner->thread_id, + lock)); + mysql_mutex_lock(&lock->mutex); + check_locks(lock,"start of release lock", lock_type, 0); + + if (((*data->prev)=data->next)) /* remove from lock-list */ + data->next->prev= data->prev; + else if (lock_type <= TL_READ_NO_INSERT) + lock->read.last=data->prev; + else if (lock_type == TL_WRITE_DELAYED && data->cond) + { + /* + This only happens in extreme circumstances when a + write delayed lock that is waiting for a lock + */ + lock->write_wait.last=data->prev; /* Put it on wait queue */ + } + else + lock->write.last=data->prev; + + if (unlock_flags & THR_UNLOCK_UPDATE_STATUS) + { + /* External lock was not called; Update or restore status */ + if (lock_type >= TL_WRITE_CONCURRENT_INSERT) + { + if (lock->update_status) + (*lock->update_status)(data->status_param); + } + else + { + if (lock->restore_status) + (*lock->restore_status)(data->status_param); + } + } + if (lock_type == TL_READ_NO_INSERT) + lock->read_no_write_count--; + data->type=TL_UNLOCK; /* Mark unlocked */ + wake_up_waiters(lock); + mysql_mutex_unlock(&lock->mutex); + DBUG_VOID_RETURN; +} + + +/** + @brief Wake up all threads which pending requests for the lock + can be satisfied. + + @param lock Lock for which threads should be woken up + +*/ + +static void wake_up_waiters(THR_LOCK *lock) +{ + THR_LOCK_DATA *data; + enum thr_lock_type lock_type; + DBUG_ENTER("wake_up_waiters"); + + check_locks(lock, "before waking up waiters", TL_UNLOCK, 1); + if (!lock->write.data) /* If no active write locks */ + { + data=lock->write_wait.data; + if (!lock->read.data) /* If no more locks in use */ + { + /* Release write-locks with TL_WRITE or TL_WRITE_ONLY priority first */ + if (data && + (data->type != TL_WRITE_LOW_PRIORITY || !lock->read_wait.data || + lock->read_wait.data->type < TL_READ_HIGH_PRIORITY)) + { + if (lock->write_lock_count++ > max_write_lock_count) + { + /* Too many write locks in a row; Release all waiting read locks */ + lock->write_lock_count=0; + if (lock->read_wait.data) + { + DBUG_PRINT("info",("Freeing all read_locks because of max_write_lock_count")); + free_all_read_locks(lock,0); + goto end; + } + } + for (;;) + { + if (((*data->prev)=data->next)) /* remove from wait-list */ + data->next->prev= data->prev; + else + lock->write_wait.last=data->prev; + (*lock->write.last)=data; /* Put in execute list */ + data->prev=lock->write.last; + data->next=0; + lock->write.last= &data->next; + if (data->type == TL_WRITE_CONCURRENT_INSERT && + (*lock->check_status)(data->status_param)) + data->type=TL_WRITE; /* Upgrade lock */ + /* purecov: begin inspected */ + DBUG_PRINT("lock",("giving write lock of type %d to thread: %lu", + data->type, (ulong) data->owner->thread_id)); + /* purecov: end */ + { + mysql_cond_t *cond= data->cond; + data->cond=0; /* Mark thread free */ + mysql_cond_signal(cond); /* Start waiting thread */ + } + if (data->type != TL_WRITE_ALLOW_WRITE || + !lock->write_wait.data || + lock->write_wait.data->type != TL_WRITE_ALLOW_WRITE) + break; + data=lock->write_wait.data; /* Free this too */ + } + if (data->type >= TL_WRITE_LOW_PRIORITY) + goto end; + /* Release possible read locks together with the write lock */ + } + if (lock->read_wait.data) + free_all_read_locks(lock, + data && + (data->type == TL_WRITE_CONCURRENT_INSERT || + data->type == TL_WRITE_ALLOW_WRITE)); + else + { + DBUG_PRINT("lock",("No waiting read locks to free")); + } + } + else if (data && + (lock_type=data->type) <= TL_WRITE_DELAYED && + ((lock_type != TL_WRITE_CONCURRENT_INSERT && + lock_type != TL_WRITE_ALLOW_WRITE) || + !lock->read_no_write_count)) + { + /* + For DELAYED, ALLOW_READ, WRITE_ALLOW_WRITE or CONCURRENT_INSERT locks + start WRITE locks together with the READ locks + */ + if (lock_type == TL_WRITE_CONCURRENT_INSERT && + (*lock->check_status)(data->status_param)) + { + data->type=TL_WRITE; /* Upgrade lock */ + if (lock->read_wait.data) + free_all_read_locks(lock,0); + goto end; + } + do { + mysql_cond_t *cond= data->cond; + if (((*data->prev)=data->next)) /* remove from wait-list */ + data->next->prev= data->prev; + else + lock->write_wait.last=data->prev; + (*lock->write.last)=data; /* Put in execute list */ + data->prev=lock->write.last; + lock->write.last= &data->next; + data->next=0; /* Only one write lock */ + data->cond=0; /* Mark thread free */ + mysql_cond_signal(cond); /* Start waiting thread */ + } while (lock_type == TL_WRITE_ALLOW_WRITE && + (data=lock->write_wait.data) && + data->type == TL_WRITE_ALLOW_WRITE); + if (lock->read_wait.data) + free_all_read_locks(lock, + (lock_type == TL_WRITE_CONCURRENT_INSERT || + lock_type == TL_WRITE_ALLOW_WRITE)); + } + else if (!data && lock->read_wait.data) + free_all_read_locks(lock,0); + } +end: + check_locks(lock, "after waking up waiters", TL_UNLOCK, 0); + DBUG_VOID_RETURN; +} + + +/* + Get all locks in a specific order to avoid dead-locks + Sort according to lock position and put write_locks before read_locks if + lock on same lock. Locks on MERGE tables has lower priority than other + locks of the same type. See comment for lock_priority. +*/ + +static void sort_locks(THR_LOCK_DATA **data,uint count) +{ + THR_LOCK_DATA **pos,**end,**prev,*tmp; + + /* Sort locks with insertion sort (fast because almost always few locks) */ + + for (pos=data+1,end=data+count; pos < end ; pos++) + { + tmp= *pos; + if (LOCK_CMP(tmp,pos[-1])) + { + prev=pos; + do { + prev[0]=prev[-1]; + } while (--prev != data && LOCK_CMP(tmp,prev[-1])); + prev[0]=tmp; + } + } +} + + +enum enum_thr_lock_result +thr_multi_lock(THR_LOCK_DATA **data, uint count, THR_LOCK_INFO *owner, + ulong lock_wait_timeout) +{ + THR_LOCK_DATA **pos, **end, **first_lock; + DBUG_ENTER("thr_multi_lock"); + DBUG_PRINT("lock",("data: %p count: %d", data, count)); + + if (count > 1) + sort_locks(data,count); + else if (count == 0) + DBUG_RETURN(THR_LOCK_SUCCESS); + + /* lock everything */ + DEBUG_SYNC_C("thr_multi_lock_before_thr_lock"); + for (pos=data,end=data+count; pos < end ; pos++) + { + enum enum_thr_lock_result result= thr_lock(*pos, owner, lock_wait_timeout); + if (result != THR_LOCK_SUCCESS) + { /* Aborted */ + thr_multi_unlock(data,(uint) (pos-data), 0); + /* Mark all requested locks as TL_UNLOCK (to simplify lock checking) */ + for ( ; pos < end ; pos++) + (*pos)->type= TL_UNLOCK; + DBUG_RETURN(result); + } +#ifdef MAIN + printf("Thread: %s Got lock:%p type: %d\n",my_thread_name(), + pos[0]->lock, pos[0]->type); fflush(stdout); +#endif + } + DEBUG_SYNC_C("thr_multi_lock_after_thr_lock"); + + /* + Call start_trans for all locks. + If we lock the same table multiple times, we must use the same + status_param; We ensure this by calling copy_status() for all + copies of the same tables. + */ + if ((*data)->lock->start_trans) + ((*data)->lock->start_trans)((*data)->status_param); + for (first_lock=data, pos= data+1 ; pos < end ; pos++) + { + /* Get the current status (row count, checksum, trid etc) */ + if ((*pos)->lock->start_trans) + (*(*pos)->lock->start_trans)((*pos)->status_param); + /* + If same table as previous table use pointer to previous status + information to ensure that all read/write tables shares same + state. + */ + if (pos[0]->lock == pos[-1]->lock && pos[0]->lock->copy_status) + (pos[0]->lock->copy_status)((*pos)->status_param, + (*first_lock)->status_param); + else + { + /* Different lock, use this as base for next lock */ + first_lock= pos; + } + } + DBUG_RETURN(THR_LOCK_SUCCESS); +} + + +/** + Merge two sets of locks. + + @param data All locks. First old locks, then new locks. + @param old_count Original number of locks. These are first in 'data'. + @param new_count How many new locks + + The merge is needed if the new locks contains same tables as the old + locks, in which case we have to ensure that same tables shares the + same status (as after a thr_multi_lock()). +*/ + +void thr_merge_locks(THR_LOCK_DATA **data, uint old_count, uint new_count) +{ + THR_LOCK_DATA **pos, **end, **first_lock= 0; + DBUG_ENTER("thr_merge_lock"); + + /* Remove marks on old locks to make them sort before new ones */ + for (pos=data, end= pos + old_count; pos < end ; pos++) + (*pos)->priority&= ~THR_LOCK_LATE_PRIV; + + /* Mark new locks with LATE_PRIV to make them sort after org ones */ + for (pos=data + old_count, end= pos + new_count; pos < end ; pos++) + (*pos)->priority|= THR_LOCK_LATE_PRIV; + + sort_locks(data, old_count + new_count); + + for (pos=data ; pos < end ; pos++) + { + /* Check if lock was unlocked before */ + if (pos[0]->type == TL_UNLOCK || ! pos[0]->lock->fix_status) + { + DBUG_PRINT("info", ("lock skipped. unlocked: %d fix_status: %d", + pos[0]->type == TL_UNLOCK, + pos[0]->lock->fix_status == 0)); + continue; + } + + /* + If same table as previous table use pointer to previous status + information to ensure that all read/write tables shares same + state. + */ + if (first_lock && pos[0]->lock == first_lock[0]->lock) + (pos[0]->lock->fix_status)((*first_lock)->status_param, + (*pos)->status_param); + else + { + /* Different lock, use this as base for next lock */ + first_lock= pos; + (pos[0]->lock->fix_status)((*first_lock)->status_param, 0); + } + } + DBUG_VOID_RETURN; +} + + +/* Unlock all locks */ + +void thr_multi_unlock(THR_LOCK_DATA **data,uint count, uint unlock_flags) +{ + THR_LOCK_DATA **pos,**end; + DBUG_ENTER("thr_multi_unlock"); + DBUG_PRINT("lock",("data: %p count: %d flags: %u", data, count, + unlock_flags)); + + for (pos=data,end=data+count; pos < end ; pos++) + { +#ifdef MAIN + printf("Thread: %s Rel lock: %p type: %d\n", + my_thread_name(), pos[0]->lock, pos[0]->type); + fflush(stdout); +#endif + if ((*pos)->type != TL_UNLOCK) + thr_unlock(*pos, unlock_flags); + else + { + DBUG_PRINT("lock",("Free lock: data: %p thread:%lu lock: %p", + *pos, (ulong) (*pos)->owner->thread_id, + (*pos)->lock)); + } + } + DBUG_VOID_RETURN; +} + +/* + Abort all threads waiting for a lock. The lock will be upgraded to + TL_WRITE_ONLY to abort any new accesses to the lock +*/ + +void thr_abort_locks(THR_LOCK *lock, my_bool upgrade_lock) +{ + THR_LOCK_DATA *data; + DBUG_ENTER("thr_abort_locks"); + mysql_mutex_lock(&lock->mutex); + + for (data=lock->read_wait.data; data ; data=data->next) + { + data->type=TL_UNLOCK; /* Mark killed */ + /* It's safe to signal the cond first: we're still holding the mutex. */ + mysql_cond_signal(data->cond); + data->cond=0; /* Removed from list */ + } + for (data=lock->write_wait.data; data ; data=data->next) + { + data->type=TL_UNLOCK; + mysql_cond_signal(data->cond); + data->cond=0; + } + lock->read_wait.last= &lock->read_wait.data; + lock->write_wait.last= &lock->write_wait.data; + lock->read_wait.data=lock->write_wait.data=0; + if (upgrade_lock && lock->write.data) + lock->write.data->type=TL_WRITE_ONLY; + mysql_mutex_unlock(&lock->mutex); + DBUG_VOID_RETURN; +} + + +/* + Abort all locks for specific table/thread combination + + This is used to abort all locks for a specific thread +*/ + +my_bool thr_abort_locks_for_thread(THR_LOCK *lock, my_thread_id thread_id) +{ + THR_LOCK_DATA *data; + my_bool found= FALSE; + DBUG_ENTER("thr_abort_locks_for_thread"); + + mysql_mutex_lock(&lock->mutex); + for (data= lock->read_wait.data; data ; data= data->next) + { + if (data->owner->thread_id == thread_id) /* purecov: tested */ + { + DBUG_PRINT("info",("Aborting read-wait lock")); + data->type= TL_UNLOCK; /* Mark killed */ + /* It's safe to signal the cond first: we're still holding the mutex. */ + found= TRUE; + mysql_cond_signal(data->cond); + data->cond= 0; /* Removed from list */ + + if (((*data->prev)= data->next)) + data->next->prev= data->prev; + else + lock->read_wait.last= data->prev; + } + } + for (data= lock->write_wait.data; data ; data= data->next) + { + if (data->owner->thread_id == thread_id) /* purecov: tested */ + { + DBUG_PRINT("info",("Aborting write-wait lock")); + data->type= TL_UNLOCK; + found= TRUE; + mysql_cond_signal(data->cond); + data->cond= 0; + + if (((*data->prev)= data->next)) + data->next->prev= data->prev; + else + lock->write_wait.last= data->prev; + } + } + wake_up_waiters(lock); + mysql_mutex_unlock(&lock->mutex); + DBUG_RETURN(found); +} + + +/* + Downgrade a WRITE_* to a lower WRITE level + SYNOPSIS + thr_downgrade_write_lock() + in_data Lock data of thread downgrading its lock + new_lock_type New write lock type + RETURN VALUE + NONE + DESCRIPTION + This can be used to downgrade a lock already owned. When the downgrade + occurs also other waiters, both readers and writers can be allowed to + start. + The previous lock is often TL_WRITE_ONLY but can also be + TL_WRITE. The normal downgrade variants are: + TL_WRITE_ONLY => TL_WRITE after a short exclusive lock while holding a + write table lock + TL_WRITE_ONLY => TL_WRITE_ALLOW_WRITE After a short exclusive lock after + already earlier having dongraded lock to TL_WRITE_ALLOW_WRITE + The implementation is conservative and rather don't start rather than + go on unknown paths to start, the common cases are handled. + + NOTE: + In its current implementation it is only allowed to downgrade from + TL_WRITE_ONLY. In this case there are no waiters. Thus no wake up + logic is required. +*/ + +void thr_downgrade_write_lock(THR_LOCK_DATA *in_data, + enum thr_lock_type new_lock_type) +{ + THR_LOCK *lock=in_data->lock; +#ifdef DBUG_ASSERT_EXISTS + enum thr_lock_type old_lock_type= in_data->type; +#endif + DBUG_ENTER("thr_downgrade_write_only_lock"); + + mysql_mutex_lock(&lock->mutex); + DBUG_ASSERT(old_lock_type == TL_WRITE_ONLY); + DBUG_ASSERT(old_lock_type > new_lock_type); + in_data->type= new_lock_type; + check_locks(lock,"after downgrading lock", old_lock_type, 0); + + mysql_mutex_unlock(&lock->mutex); + DBUG_VOID_RETURN; +} + +/* Upgrade a WRITE_DELAY lock to a WRITE_LOCK */ + +my_bool thr_upgrade_write_delay_lock(THR_LOCK_DATA *data, + enum thr_lock_type new_lock_type, + ulong lock_wait_timeout) +{ + THR_LOCK *lock=data->lock; + enum enum_thr_lock_result res; + DBUG_ENTER("thr_upgrade_write_delay_lock"); + + mysql_mutex_lock(&lock->mutex); + if (data->type == TL_UNLOCK || data->type >= TL_WRITE_LOW_PRIORITY) + { + mysql_mutex_unlock(&lock->mutex); + DBUG_RETURN(data->type == TL_UNLOCK); /* Test if Aborted */ + } + check_locks(lock,"before upgrading lock", data->type, 0); + /* TODO: Upgrade to TL_WRITE_CONCURRENT_INSERT in some cases */ + data->type= new_lock_type; /* Upgrade lock */ + + /* Check if someone has given us the lock */ + if (!data->cond) + { + if (!lock->read.data) /* No read locks */ + { /* We have the lock */ + /* For this function, get_status is not allowed to fail */ + if (data->lock->get_status) + (*data->lock->get_status)(data->status_param, 0); + mysql_mutex_unlock(&lock->mutex); + if (lock->start_trans) + (*lock->start_trans)(data->status_param); + DBUG_RETURN(0); + } + + if (((*data->prev)=data->next)) /* remove from lock-list */ + data->next->prev= data->prev; + else + lock->write.last=data->prev; + + if ((data->next=lock->write_wait.data)) /* Put first in lock_list */ + data->next->prev= &data->next; + else + lock->write_wait.last= &data->next; + data->prev= &lock->write_wait.data; + lock->write_wait.data=data; + check_locks(lock,"upgrading lock", new_lock_type, 0); + } + else + { + check_locks(lock,"waiting for lock", new_lock_type, 0); + } + res= wait_for_lock(&lock->write_wait, data, 1, lock_wait_timeout); + if (res == THR_LOCK_SUCCESS && lock->start_trans) + DBUG_RETURN((*lock->start_trans)(data->status_param)); + DBUG_RETURN(0); +} + + +/* downgrade a WRITE lock to a WRITE_DELAY lock if there is pending locks */ + +my_bool thr_reschedule_write_lock(THR_LOCK_DATA *data, + ulong lock_wait_timeout) +{ + THR_LOCK *lock=data->lock; + enum thr_lock_type write_lock_type; + DBUG_ENTER("thr_reschedule_write_lock"); + + mysql_mutex_lock(&lock->mutex); + if (!lock->read_wait.data) /* No waiting read locks */ + { + mysql_mutex_unlock(&lock->mutex); + DBUG_RETURN(0); + } + + write_lock_type= data->type; + data->type=TL_WRITE_DELAYED; + if (lock->update_status) + (*lock->update_status)(data->status_param); + if (((*data->prev)=data->next)) /* remove from lock-list */ + data->next->prev= data->prev; + else + lock->write.last=data->prev; + + if ((data->next=lock->write_wait.data)) /* Put first in lock_list */ + data->next->prev= &data->next; + else + lock->write_wait.last= &data->next; + data->prev= &lock->write_wait.data; + data->cond=get_cond(); /* This was zero */ + lock->write_wait.data=data; + free_all_read_locks(lock,0); + + mysql_mutex_unlock(&lock->mutex); + DBUG_RETURN(thr_upgrade_write_delay_lock(data, write_lock_type, + lock_wait_timeout)); +} + + +#include <my_sys.h> + +static void thr_print_lock(const char* name,struct st_lock_list *list) +{ + THR_LOCK_DATA *data,**prev; + uint count=0; + + if (list->data) + { + printf("%-10s: ",name); + prev= &list->data; + for (data=list->data; data && count++ < MAX_LOCKS ; data=data->next) + { + printf("%p (%lu:%d); ", data, (ulong) data->owner->thread_id, + (int) data->type); + if (data->prev != prev) + printf("\nWarning: prev didn't point at previous lock\n"); + prev= &data->next; + } + puts(""); + if (prev != list->last) + printf("Warning: last didn't point at last lock\n"); + } +} + +void thr_print_locks(void) +{ + LIST *list; + uint count=0; + + mysql_mutex_lock(&THR_LOCK_lock); + puts("Current active THR (table level locks):"); + for (list= thr_lock_thread_list; list && count++ < MAX_THREADS; + list= list_rest(list)) + { + THR_LOCK *lock=(THR_LOCK*) list->data; + mysql_mutex_lock(&lock->mutex); + if ((lock->write.data || lock->read.data || + lock->write_wait.data || lock->read_wait.data)) + { + printf("lock: %p:", lock); + if ((lock->write_wait.data || lock->read_wait.data) && + (! lock->read.data && ! lock->write.data)) + printf(" WARNING: "); + if (lock->write.data) + printf(" write"); + if (lock->write_wait.data) + printf(" write_wait"); + if (lock->read.data) + printf(" read"); + if (lock->read_wait.data) + printf(" read_wait"); + puts(""); + thr_print_lock("write",&lock->write); + thr_print_lock("write_wait",&lock->write_wait); + thr_print_lock("read",&lock->read); + thr_print_lock("read_wait",&lock->read_wait); + puts(""); + } + mysql_mutex_unlock(&lock->mutex); + } + fflush(stdout); + mysql_mutex_unlock(&THR_LOCK_lock); +} + + +/***************************************************************************** +** Test of thread locks +****************************************************************************/ + +#ifdef MAIN + +struct st_test { + uint lock_nr; + enum thr_lock_type lock_type; +}; + +THR_LOCK locks[6]; /* Number of locks +1 */ + +struct st_test test_0[] = {{0,TL_READ}}; /* One lock */ +struct st_test test_1[] = {{0,TL_READ},{0,TL_WRITE}}; /* Read and write lock of lock 0 */ +struct st_test test_2[] = {{1,TL_WRITE},{0,TL_READ},{2,TL_READ}}; +struct st_test test_3[] = {{2,TL_WRITE},{1,TL_READ},{0,TL_READ}}; /* Deadlock with test_2 ? */ +struct st_test test_4[] = {{0,TL_WRITE},{0,TL_READ},{0,TL_WRITE},{0,TL_READ}}; +struct st_test test_5[] = {{0,TL_READ},{1,TL_READ},{2,TL_READ},{3,TL_READ}}; /* Many reads */ +struct st_test test_6[] = {{0,TL_WRITE},{1,TL_WRITE},{2,TL_WRITE},{3,TL_WRITE}}; /* Many writes */ +struct st_test test_7[] = {{3,TL_READ}}; +struct st_test test_8[] = {{1,TL_READ_NO_INSERT},{2,TL_READ_NO_INSERT},{3,TL_READ_NO_INSERT}}; /* Should be quick */ +struct st_test test_9[] = {{4,TL_READ_HIGH_PRIORITY}}; +struct st_test test_10[] ={{4,TL_WRITE}}; +struct st_test test_11[] = {{0,TL_WRITE_LOW_PRIORITY},{1,TL_WRITE_LOW_PRIORITY},{2,TL_WRITE_LOW_PRIORITY},{3,TL_WRITE_LOW_PRIORITY}}; /* Many writes */ +struct st_test test_12[] = {{0,TL_WRITE_CONCURRENT_INSERT},{1,TL_WRITE_CONCURRENT_INSERT},{2,TL_WRITE_CONCURRENT_INSERT},{3,TL_WRITE_CONCURRENT_INSERT}}; +struct st_test test_13[] = {{0,TL_WRITE_CONCURRENT_INSERT},{1,TL_READ}}; +struct st_test test_14[] = {{0,TL_WRITE_ALLOW_WRITE},{1,TL_READ}}; +struct st_test test_15[] = {{0,TL_WRITE_ALLOW_WRITE},{1,TL_WRITE_ALLOW_WRITE}}; + +struct st_test *tests[] = {test_0,test_1,test_2,test_3,test_4,test_5,test_6, + test_7,test_8,test_9,test_10,test_11,test_12, + test_13,test_14,test_15}; +int lock_counts[]= {sizeof(test_0)/sizeof(struct st_test), + sizeof(test_1)/sizeof(struct st_test), + sizeof(test_2)/sizeof(struct st_test), + sizeof(test_3)/sizeof(struct st_test), + sizeof(test_4)/sizeof(struct st_test), + sizeof(test_5)/sizeof(struct st_test), + sizeof(test_6)/sizeof(struct st_test), + sizeof(test_7)/sizeof(struct st_test), + sizeof(test_8)/sizeof(struct st_test), + sizeof(test_9)/sizeof(struct st_test), + sizeof(test_10)/sizeof(struct st_test), + sizeof(test_11)/sizeof(struct st_test), + sizeof(test_12)/sizeof(struct st_test), + sizeof(test_13)/sizeof(struct st_test), + sizeof(test_14)/sizeof(struct st_test), + sizeof(test_15)/sizeof(struct st_test) +}; + + +static mysql_cond_t COND_thread_count; +static mysql_mutex_t LOCK_thread_count; +static uint thread_count; +static ulong sum=0; + +#define MAX_LOCK_COUNT 8 +#define TEST_TIMEOUT 100000 + +/* The following functions is for WRITE_CONCURRENT_INSERT */ + +static my_bool test_get_status(void* param __attribute__((unused)), + my_bool concurrent_insert __attribute__((unused))) +{ + return 0; +} + +static void test_update_status(void* param __attribute__((unused))) +{ +} + +static void test_copy_status(void* to __attribute__((unused)) , + void *from __attribute__((unused))) +{ +} + +static my_bool test_check_status(void* param __attribute__((unused))) +{ + return 0; +} + + +static void *test_thread(void *arg) +{ + int i,j,param=*((int*) arg); + THR_LOCK_DATA data[MAX_LOCK_COUNT]; + THR_LOCK_INFO lock_info; + THR_LOCK_DATA *multi_locks[MAX_LOCK_COUNT]; + my_thread_init(); + + printf("Thread %s (%d) started\n",my_thread_name(),param); fflush(stdout); + + thr_lock_info_init(&lock_info, 0); + for (i=0; i < lock_counts[param] ; i++) + thr_lock_data_init(locks+tests[param][i].lock_nr,data+i,NULL); + for (j=1 ; j < 10 ; j++) /* try locking 10 times */ + { + for (i=0; i < lock_counts[param] ; i++) + { /* Init multi locks */ + multi_locks[i]= &data[i]; + data[i].type= tests[param][i].lock_type; + } + thr_multi_lock(multi_locks, lock_counts[param], &lock_info, TEST_TIMEOUT); + mysql_mutex_lock(&LOCK_thread_count); + { + int tmp=rand() & 7; /* Do something from 0-2 sec */ + if (tmp == 0) + sleep(1); + else if (tmp == 1) + sleep(2); + else + { + ulong k; + for (k=0 ; k < (ulong) (tmp-2)*100000L ; k++) + sum+=k; + } + } + mysql_mutex_unlock(&LOCK_thread_count); + thr_multi_unlock(multi_locks,lock_counts[param], THR_UNLOCK_UPDATE_STATUS); + } + + printf("Thread %s (%d) ended\n",my_thread_name(),param); fflush(stdout); + thr_print_locks(); + mysql_mutex_lock(&LOCK_thread_count); + thread_count--; + mysql_cond_signal(&COND_thread_count); /* Tell main we are ready */ + mysql_mutex_unlock(&LOCK_thread_count); + my_thread_end(); + return 0; +} + + +int main(int argc __attribute__((unused)),char **argv __attribute__((unused))) +{ + pthread_t tid; + pthread_attr_t thr_attr; + int param[array_elements(lock_counts)], error; + uint i; + MY_INIT(argv[0]); + if (argc > 1 && argv[1][0] == '-' && argv[1][1] == '#') + DBUG_PUSH(argv[1]+2); + + printf("Main thread: %s\n",my_thread_name()); + + if ((error= mysql_cond_init(0, &COND_thread_count, NULL))) + { + fprintf(stderr, "Got error: %d from mysql_cond_init (errno: %d)", + error,errno); + exit(1); + } + if ((error= mysql_mutex_init(0, &LOCK_thread_count, MY_MUTEX_INIT_FAST))) + { + fprintf(stderr, "Got error: %d from mysql_cond_init (errno: %d)", + error,errno); + exit(1); + } + + for (i=0 ; i < array_elements(locks) ; i++) + { + thr_lock_init(locks+i); + locks[i].check_status= test_check_status; + locks[i].update_status=test_update_status; + locks[i].copy_status= test_copy_status; + locks[i].get_status= test_get_status; + locks[i].allow_multiple_concurrent_insert= 1; + } + if ((error=pthread_attr_init(&thr_attr))) + { + fprintf(stderr,"Got error: %d from pthread_attr_init (errno: %d)", + error,errno); + exit(1); + } + if ((error=pthread_attr_setdetachstate(&thr_attr,PTHREAD_CREATE_DETACHED))) + { + fprintf(stderr, + "Got error: %d from pthread_attr_setdetachstate (errno: %d)", + error,errno); + exit(1); + } +#ifndef pthread_attr_setstacksize /* void return value */ + if ((error=pthread_attr_setstacksize(&thr_attr,65536L))) + { + fprintf(stderr,"Got error: %d from pthread_attr_setstacksize (errno: %d)", + error,errno); + exit(1); + } +#endif +#ifdef HAVE_THR_SETCONCURRENCY + (void) thr_setconcurrency(2); +#endif + for (i=0 ; i < array_elements(lock_counts) ; i++) + { + param[i]= i; + + if ((error= mysql_mutex_lock(&LOCK_thread_count))) + { + fprintf(stderr, "Got error: %d from mysql_mutex_lock (errno: %d)", + error, errno); + exit(1); + } + if ((error= mysql_thread_create(0, + &tid, &thr_attr, test_thread, + (void*) ¶m[i]))) + { + fprintf(stderr, "Got error: %d from mysql_thread_create (errno: %d)\n", + error, errno); + mysql_mutex_unlock(&LOCK_thread_count); + exit(1); + } + thread_count++; + mysql_mutex_unlock(&LOCK_thread_count); + } + + pthread_attr_destroy(&thr_attr); + if ((error= mysql_mutex_lock(&LOCK_thread_count))) + fprintf(stderr, "Got error: %d from mysql_mutex_lock\n", error); + while (thread_count) + { + if ((error= mysql_cond_wait(&COND_thread_count, &LOCK_thread_count))) + fprintf(stderr, "Got error: %d from mysql_cond_wait\n", error); + } + if ((error= mysql_mutex_unlock(&LOCK_thread_count))) + fprintf(stderr, "Got error: %d from mysql_mutex_unlock\n", error); + for (i=0 ; i < array_elements(locks) ; i++) + thr_lock_delete(locks+i); +#ifdef EXTRA_DEBUG + if (found_errors) + printf("Got %d warnings\n",found_errors); + else +#endif + printf("Test succeeded\n"); + mysql_cond_destroy(&COND_thread_count); + mysql_mutex_destroy(&LOCK_thread_count); + my_end(MY_CHECK_ERROR); + return 0; +} + +#endif /* MAIN */ |