InnoDB INFORMATION_SCHEMA Schema Object Tables acquired by a transaction, all incompatible lock requests previously entered into the lock queue for that row or table must be removed (which occurs when the transactions holding or requesting those locks either commit or roll back). A transaction may have any number of lock requests for different rows or tables. At any given time, a transaction may request a lock that is held by another transaction, in which case it is blocked by that other transaction. The requesting transaction must wait for the transaction that holds the blocking lock to commit or roll back. If a transaction is not waiting for a lock, it is in a  RUNNING  state. If a transaction is waiting for a lock, it is in a  LOCK WAIT  state. (The  INFORMATION_SCHEMA INNODB_TRX  table indicates transaction state values.) The Performance Schema  data_locks  table holds one or more rows for each  LOCK WAIT  transaction, indicating any lock requests that prevent its progress. This table also contains one row describing each lock in a queue of locks pending for a given row or table. The Performance Schema  data_lock_waits table shows which locks already held by a transaction are blocking locks requested by other transactions. This section describes locking information as exposed by the Performance Schema  data_locks  and  data_lock_waits  tables, which supersede the  INFORMATION_SCHEMA INNODB_LOCKS  and  INNODB_LOCK_WAITS tables in MySQL 8.0. For similar discussion written in terms of the older INFORMATION_SCHEMA  tables, see Persistence and Consistency of InnoDB Transaction and Locking Information, in MySQL 5.7 Reference Manual. The data exposed by the transaction and locking tables ( INFORMATION_SCHEMA INNODB_TRX  table, Performance Schema  data_locks  and  data_lock_waits  tables) represents a glimpse into fast- changing data. This is not like user tables, where the data changes only when application-initiated updates occur. The underlying data is internal system-managed data, and can change very quickly: The  data_locks  and  data_lock_waits  tables expose live data from the  InnoDB  storage engine, to provide lock inormation about the transactions in the  INNODB_TRX  table. Data retrieved from the lock tables exists when the  SELECT  is executed, but might be gone or changed by the time the query result is consumed by the client. Joining  data_locks  with  data_lock_waits  can show rows in  data_lock_waits  that identify a parent row in  data_locks  that no longer exists or does not exist yet. For example, you should be careful when comparing data in the  InnoDB  transaction and locking tables with data in the  PROCESSLIST  table. Even if you issue a single  SELECT  (joining  INNODB_TRX and  PROCESSLIST , for example), the content of those tables is generally not consistent. It is possible for  INNODB_TRX  to reference rows that are not present in  PROCESSLIST  or for the currently executing SQL query of a transaction shown in  INNODB_TRX.TRX_QUERY  to differ from the one in PROCESSLIST.INFO . You can extract metadata about schema objects managed by  InnoDB  using  InnoDB INFORMATION_SCHEMA  tables. This information comes from the data dictionary. Traditionally, you would 3307 15.15.3 InnoDB INFORMATION_SCHEMA Schema Object Tables 15.15.2.3 Persistence and Consistency of InnoDB Transaction and Locking Information Note •Data might not be consistent between the  INNODB_TRX ,  data_locks , and  data_lock_waits  tables. •Data in the transaction and locking tables might not be consistent with data in the INFORMATION_SCHEMA PROCESSLIST  table or Performance Schema  threads  table.