INNODB_TRX: Contains information about every transaction currently executing inside
InnoDB, including whether the transaction is waiting for a lock, when the transaction started, and the particular SQL statement the transaction is executing.
INNODB_LOCKS: Each transaction in InnoDB that is waiting for another transaction to release a lock (
INNODB_TRX.TRX_STATE='LOCK WAIT') is blocked by exactly one “blocking lock request”. That blocking lock request is for a row or table lock held by another transaction in an incompatible mode. The waiting or blocked transaction cannot proceed until the other transaction commits or rolls back, thereby releasing the requested lock. For every blocked transaction,
INNODB_LOCKScontains one row that describes each lock the transaction has requested, and for which it is waiting.
INNODB_LOCKSalso contains one row for each lock that is blocking another transaction, whatever the state of the transaction that holds the lock (
'COMMITTING'). The lock that is blocking a transaction is always held in a mode (read vs. write, shared vs. exclusive) incompatible with the mode of requested lock.
INNODB_LOCK_WAITS: Using this table, you can tell which transactions are waiting for a given lock, or for which lock a given transaction is waiting. This table contains one or more rows for each blocked transaction, indicating the lock it has requested and any locks that are blocking that request. The
REQUESTED_LOCK_IDrefers to the lock that a transaction is requesting, and the
BLOCKING_LOCK_IDrefers to the lock (held by another transaction) that is preventing the first transaction from proceeding. For any given blocked transaction, all rows in
INNODB_LOCK_WAITShave the same value for
REQUESTED_LOCK_IDand different values for