ORA-19573: cannot obtain exclusive enqueue for datafile XXX 解决方法

ORA-19573: cannot obtain exclusive enqueue for datafile XXX 解决方法
 
一个朋友说自己使用RMAN进行恢复datafile 3，出现ORA-19573，不能正常恢复。与朋友沟通，朋友执行恢复的时候，竟还有实例处于OPEN状态。把所有实例mount后，恢复成功
 
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of restore command at 07/26/2013 11:45:33
ORA-19870: error while restoring backup piece /rman/backup/data/level0_RACDB_93_1_2tofn3hn_20130726.bak
ORA-19573: cannot obtain exclusive enqueue for datafile 3
 
[oracle@racdb 2 rman]$ oerr ora 19573
19573, 00000, "cannot obtain %s enqueue for datafile %s"
// *Cause:  The file access enqueue could not be obtained for a file
//          specified in a backup, copy or restore operation.
//          If the enqueue type shown is 'shared', then the file is the
//          input file for a backup or copy.  If the type is 'exclusive', then
//          the file is the output file for a datafile copy or restore which
//          is attempting to overwrite the currently active version of that
//          file - in this case, the file must be offline or the database must
//          be closed.  If the type is 'read-only', then you are attempting
//          to back up or copy this file while the database is in NOARCHIVELOG
//          mode.
// *Action: Wait until the conflicting operation is complete, then retry
//          the copy or backup.  If the database is in NOARCHIVELOG mode, then
//          all files being backed up must be closed cleanly.
 
 
解决方法：所有实例mount状态下执行恢复！