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Reduce conflict during in-order replication.

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This commit is contained in:
sensssz
2016-10-12 21:52:14 -04:00
parent 55d2bff882
commit 5dc7ad87b8
2 changed files with 30 additions and 0 deletions
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15
storage/innobase/lock/lock0lock.cc
View File

@@ -388,6 +388,9 @@ extern "C" int thd_need_wait_for(const MYSQL_THD thd);
extern "C"
int thd_need_ordering_with(const MYSQL_THD thd, const MYSQL_THD other_thd);
extern "C"
int thd_deadlock_victim_preference(const MYSQL_THD thd1, const MYSQL_THD thd2);
/** Stack to use during DFS search. Currently only a single stack is required
because there is no parallel deadlock check. This stack is protected by
the lock_sys_t::mutex. */
@@ -1988,6 +1991,8 @@ wsrep_print_wait_locks(
/*********************************************************************//**
Check if lock1 has higher priority than lock2.
NULL has lowest priority.
Respect the preference of the upper server layer to reduce conflict
during in-order parallel replication.
If neither of them is wait lock, the first one has higher priority.
If only one of them is a wait lock, it has lower priority.
Otherwise, the one with an older transaction has higher priority.
@@ -2002,6 +2007,16 @@ has_higher_priority(
} else if (lock2 == NULL) {
return true;
}
// Ask the upper server layer if any of the two trx should be prefered.
int preference = thd_deadlock_victim_preference(lock1->thd, lock2->thd);
if (preference == -1) {
// lock1 is preferred as a victim, so lock2 has higher priority
return false;
} else if (preference == 1) {
// lock2 is preferred as a victim, so lock1 has higher priority
return true;
}
// No preference. Compre them by wait mode and trx age.
if (!lock_get_wait(lock1)) {
return true;
} else if (!lock_get_wait(lock2)) {

15
storage/xtradb/lock/lock0lock.cc
View File

@@ -388,6 +388,9 @@ extern "C" int thd_need_wait_for(const MYSQL_THD thd);
extern "C"
int thd_need_ordering_with(const MYSQL_THD thd, const MYSQL_THD other_thd);
extern "C"
int thd_deadlock_victim_preference(const MYSQL_THD thd1, const MYSQL_THD thd2);
/** Stack to use during DFS search. Currently only a single stack is required
because there is no parallel deadlock check. This stack is protected by
the lock_sys_t::mutex. */
@@ -2011,6 +2014,8 @@ wsrep_print_wait_locks(
/*********************************************************************//**
Check if lock1 has higher priority than lock2.
NULL has lowest priority.
Respect the preference of the upper server layer to reduce conflict
during in-order parallel replication.
If neither of them is wait lock, the first one has higher priority.
If only one of them is a wait lock, it has lower priority.
Otherwise, the one with an older transaction has higher priority.
@@ -2025,6 +2030,16 @@ has_higher_priority(
} else if (lock2 == NULL) {
return true;
}
// Ask the upper server layer if any of the two trx should be prefered.
int preference = thd_deadlock_victim_preference(lock1->thd, lock2->thd);
if (preference == -1) {
// lock1 is preferred as a victim, so lock2 has higher priority
return false;
} else if (preference == 1) {
// lock2 is preferred as a victim, so lock1 has higher priority
return true;
}
// No preference. Compre them by wait mode and trx age.
if (!lock_get_wait(lock1)) {
return true;
} else if (!lock_get_wait(lock2)) {