ndbinfo: The NDB Cluster Information Database • state • detail • op • duration_millis • lock_num • waiting_for Lock state Whether this is first holding lock in row lock queue Operation type Milliseconds spent waiting or holding lock ID of lock object Waiting for lock with this ID The  mysql_connection_id  column shows the MySQL connection or thread ID as shown by  SHOW PROCESSLIST . block_instance  refers to an instance of a kernel block. Together with the block name, this number can be used to look up a given instance in the  threadblocks  table. The  tableid  is assigned to the table by  NDB ; the same ID is used for this table in other  ndbinfo  tables, as well as in the output of  ndb_show_tables . The transaction ID shown in the  transid  column is the identifier generated by the NDB API for the transaction requesting or holding the current lock. The  mode  column shows the lock mode, which is always one of  S  (shared lock) or  X  (exclusive lock). If a transaction has an exclusive lock on a given row, all other locks on that row have the same transaction ID. The  state  column shows the lock state. Its value is always one of  H  (holding) or  W  (waiting). A waiting lock request waits for a lock held by a different transaction. The  detail  column indicates whether this lock is the first holding lock in the affected row’s lock queue, in which case it contains a  *  (asterisk character); otherwise, this column is empty. This information can be used to help identify the unique entries in a list of lock requests. The  op  column shows the type of operation requesting the lock. This is always one of the values  READ , INSERT ,  UPDATE ,  DELETE ,  SCAN , or  REFRESH . The  duration_millis  column shows the number of milliseconds for which this lock request has been waiting or holding the lock. This is reset to 0 when a lock is granted for a waiting request. The lock ID ( lockid  column) is unique to this node and block instance. If the  lock_state  column’s value is  W , this lock is waiting to be granted, and the  waiting_for  column shows the lock ID of the lock object this request is waiting for. Otherwise,  waiting_for  is empty. waiting_for  can refer only to locks on the same row (as identified by  node_id ,  block_instance , tableid ,  fragmentid , and  rowid ). 4579 Notes