rman operation very slow, found dbms_rcvcat.lockForckpt takes long time

Hi guys,

I met a rman performance issue. There are several dbid in rman catalog, other db perform normal, but one db is very slow in rman operation. To narrow the problem, I use vey simple rman commnds and trace to see what happened. The commnds are :

run{

allocate channel c1 type disk;

sql 'alter system archive log current';

}

This simple operation cost about 50 minutes. In the trace, found following sentense 6 times, each takes 5-6 minutes:

DBGSQL:      EXEC SQL AT RCVCAT begin dbms_rcvcat . lockForckpt ; end ; [16:46:40.728]
DBGSQL:         sqlcode=0 [16:52:41.065]
   DBGRCVCAT: lockForCkpt: Obtained all locks for incarnation 1244084

Anyone can give some idea to tune this? Thanks a lot!