diff options
Diffstat (limited to 'sql/lock.cc')
| -rw-r--r-- | sql/lock.cc | 51 |
1 files changed, 49 insertions, 2 deletions
diff --git a/sql/lock.cc b/sql/lock.cc index a8ccba32d4f..83a39005cd8 100644 --- a/sql/lock.cc +++ b/sql/lock.cc @@ -82,7 +82,8 @@ static int unlock_external(THD *thd, TABLE **table,uint count); static void print_lock_error(int error, const char *); -MYSQL_LOCK *mysql_lock_tables(THD *thd,TABLE **tables,uint count) +MYSQL_LOCK *mysql_lock_tables(THD *thd, TABLE **tables, uint count, + bool ignore_global_read_lock) { MYSQL_LOCK *sql_lock; TABLE *write_lock_used; @@ -93,7 +94,7 @@ MYSQL_LOCK *mysql_lock_tables(THD *thd,TABLE **tables,uint count) if (!(sql_lock = get_lock_data(thd,tables,count, 0,&write_lock_used))) break; - if (global_read_lock && write_lock_used) + if (global_read_lock && write_lock_used && ! ignore_global_read_lock) { /* Someone has issued LOCK ALL TABLES FOR READ and we want a write lock @@ -949,3 +950,49 @@ bool make_global_read_lock_block_commit(THD *thd) DBUG_RETURN(error); } + + +/* + Set protection against global read lock. + + SYNOPSIS + set_protect_against_global_read_lock() + void + + RETURN + FALSE OK, no global read lock exists. + TRUE Error, global read lock exists already. +*/ + +bool set_protect_against_global_read_lock(void) +{ + bool global_read_lock_exists; + + pthread_mutex_lock(&LOCK_open); + if (! (global_read_lock_exists= test(global_read_lock))) + protect_against_global_read_lock++; + pthread_mutex_unlock(&LOCK_open); + return global_read_lock_exists; +} + + +/* + Unset protection against global read lock. + + SYNOPSIS + unset_protect_against_global_read_lock() + void + + RETURN + void +*/ + +void unset_protect_against_global_read_lock(void) +{ + pthread_mutex_lock(&LOCK_open); + protect_against_global_read_lock--; + pthread_mutex_unlock(&LOCK_open); + pthread_cond_broadcast(&COND_refresh); +} + + |