MySQL 9.5 Reference Manual Including MySQL NDB Cluster 9.5
        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:
      
            Data might not be consistent between the
            INNODB_TRX,
            data_locks, and
            data_lock_waits tables.
          
            The data_locks and
            data_lock_waits tables expose
            live data from the InnoDB storage engine,
            to provide lock information 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.
          
            Data in the transaction and locking tables might not be
            consistent with data in the
            INFORMATION_SCHEMA
            PROCESSLIST table or
            Performance Schema threads
            table.
          
            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.