diff options
Diffstat (limited to 'sql/mdl.cc')
| -rw-r--r-- | sql/mdl.cc | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/sql/mdl.cc b/sql/mdl.cc index 28d2006b023..37699f1847b 100644 --- a/sql/mdl.cc +++ b/sql/mdl.cc @@ -17,6 +17,7 @@ #include "sql_class.h" #include "debug_sync.h" #include "sql_array.h" +#include "rpl_rli.h" #include <hash.h> #include <mysqld_error.h> #include <mysql/plugin.h> @@ -442,6 +443,7 @@ public: virtual void notify_conflicting_locks(MDL_context *ctx) = 0; virtual bitmap_t hog_lock_types_bitmap() const = 0; + bool check_if_conflicting_replication_locks(MDL_context *ctx); /** List of granted tickets for this lock. */ Ticket_list m_granted; @@ -2290,6 +2292,44 @@ void MDL_scoped_lock::notify_conflicting_locks(MDL_context *ctx) } } +/** + Check if there is any conflicting lock that could cause this thread + to wait for another thread which is not ready to commit. + This is always an error, as the upper level of parallel replication + should not allow a scheduling of a conflicting DDL until all earlier + transactions has commited. + + This function is only called for a slave using parallel replication + and trying to get an exclusive lock for the table. +*/ + +bool MDL_lock::check_if_conflicting_replication_locks(MDL_context *ctx) +{ + Ticket_iterator it(m_granted); + MDL_ticket *conflicting_ticket; + + while ((conflicting_ticket= it++)) + { + if (conflicting_ticket->get_ctx() != ctx) + { + MDL_context *conflicting_ctx= conflicting_ticket->get_ctx(); + + /* + If the conflicting thread is another parallel replication + thread for the same master and it's not in commit stage, then + the current transaction has started too early and something is + seriously wrong. + */ + if (conflicting_ctx->get_thd()->rgi_slave && + conflicting_ctx->get_thd()->rgi_slave->rli == + ctx->get_thd()->rgi_slave->rli && + !conflicting_ctx->get_thd()->rgi_slave->did_mark_start_commit) + return 1; // Fatal error + } + } + return 0; +} + /** Acquire one lock with waiting for conflicting locks to go away if needed. @@ -2355,6 +2395,19 @@ MDL_context::acquire_lock(MDL_request *mdl_request, ulong lock_wait_timeout) if (lock->needs_notification(ticket) && lock_wait_timeout) lock->notify_conflicting_locks(this); + /* + Ensure that if we are trying to get an exclusive lock for a slave + running parallel replication, then we are not blocked by another + parallel slave thread that is not committed. This should never happen as + the parallel replication scheduler should never schedule a DDL while + DML's are still running. + */ + DBUG_ASSERT((mdl_request->type != MDL_INTENTION_EXCLUSIVE && + mdl_request->type != MDL_EXCLUSIVE) || + !(get_thd()->rgi_slave && + get_thd()->rgi_slave->is_parallel_exec && + lock->check_if_conflicting_replication_locks(this))); + mysql_prlock_unlock(&lock->m_rwlock); will_wait_for(ticket); |