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！