Error handling in InnoDB is not always the same
      as specified in the SQL standard. According to the standard, any
      error during an SQL statement should cause rollback of that
      statement. InnoDB sometimes rolls back only
      part of the statement, or the whole transaction. The following
      items describe how InnoDB performs error
      handling:
    
          If you run out of file space in the tablespace, a MySQL
          Table is full error occurs and
          InnoDB rolls back the SQL statement.
        
          A transaction deadlock or a timeout in a lock wait causes
          InnoDB to roll back the whole transaction.
        
Both deadlocks and lock wait timeouts are normal on busy servers and it is necessary for applications to be aware that they may happen and handle them by retrying. You can make them less likely by doing as little work as possible between the first change to data during a transaction and the commit, so the locks are held for the shortest possible time and for the smallest possible number of rows. Sometimes splitting work between different transactions may be practical and helpful.
          When a transaction rollback occurs due to a deadlock or lock
          wait timeout, it cancels the effect of the statements within
          the transaction. But if the start-transaction statement was
          START
          TRANSACTION or
          BEGIN
          statement, rollback does not cancel that statement. Further
          SQL statements become part of the transaction until the
          occurrence of COMMIT,
          ROLLBACK, or
          some SQL statement that causes an implicit commit.
        
          A duplicate-key error rolls back the SQL statement, if you
          have not specified the IGNORE option in
          your statement.
        
          A row too long error rolls back the SQL
          statement.
        
          Other errors are mostly detected by the MySQL layer of code
          (above the InnoDB storage engine level),
          and they roll back the corresponding SQL statement. Locks are
          not released in a rollback of a single SQL statement.
        
      During such implicit rollbacks, as well as during the explicit
      ROLLBACK SQL
      statement, SHOW PROCESSLIST
      displays "Rolling back" in the State column for
      the connection (starting from MySQL 4.1.8).
    

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