I was trying to restore Oracle database on another host and after open database with resetlogs option in alert.log file appear below internal error:
ORA-00600: internal error code, arguments: [qcisSetPlsqlCtx:tzi init], [], [], [], [], [], [], [], [], [], [], []
Beside this, database was working very slowly, every command was working extremely slowly and overall database working was unresponsive.
Solution:
1) Check files under $ORACLE_HOME/oracore/zoneinfo directory on database server, where backup is taken and replace files on local $ORACLE_HOME/oracore/zoneinfo where restore is done.
2) Restart database and everything is going smoothly.