RMAN-20035

I received this error today while configuring RMAN on one of the databases.

RMAN-20035: Invalid high RECID error

In this case Note 273446.1 from Oracle support was helpful.

It suggests to unregister the database using DBMS_RCVCAT.UNREGISTERDATABASE procedure.
and then register the database again.

This is what i did and the problem resolved as of now.
The following commands are helpful -->

select * from rc_database where dbid = DBID;

exec dbms_rcvcat.unregisterdatabase(DBKEY, DBID);

ORA-00600: internal error code, arguments: [4194],[],[]

I have very less experience in recovery of databases. However recently i have recovered big databases and in one of the databases i saw the error-
ORA-00600: internal error code, arguments: [4194],
Doing block recovery for file 5 block 18791
Block recovery from logseq 4237, block 76 to scn 6058257035817
This was continuously coming in alert log.
After searching for a while a solution that i came across was to drop undo table space and recreate it. And this is what i did and the error got resolved.
Hope this helps