RMAN

You have lost datafiles and you dont have backup and database is not running in archive log mode……
So we need to recreate the datafiles which will be empty….. you can not recover, becuase you dont have backup and database not in archive log mode

Restore it from Full backup and recover that data file using archive log files which are after Full backup to till date

Once current redolog file is damaged, instance is aborted and it needs recovery upto undamaged part. Only undamaged part can be recovered. Here DBA must apply time based recovery, means it can be a point in time or specified by SCN.

It leads to incomplete recovery

CONFIGURE RETENTION POLICY TO REDUNDANCY 3

Yes. We can perform online table redefinition with the Enterprise Manager Reorganize Objects wizard or with the DBMS_REDEFINITION package.

# df -h

The output will be

Filesystem Size Used Avail Use% Mounted on
/dev/hda3 75G 17G 54G 24% /
/dev/hda1 99M 17M 78M 18% /boot
none 505M 0 505M 0% /dev/shm
/tmp 243M 7.2M 223M 4% /tmp

Here the size is represented by megabytes and gigabytes.
Now let’s create an executable file to show the disk sizes:

#!/bin/sh

DISC=$1
PARTITION=`df -h |grep $DISC |awk ‘{print $1}’`
SIZE=`df -h|grep $DISC|awk ‘{print $2}’`
USED=`df -h|grep $DISC|awk ‘{print $3}’`
FREE=`df -h|grep $DISC|awk ‘{print $4}’`

echo “Partition: $PARTITION”
echo “Total size: $SIZE”
echo “Used space: $USED”
echo “Free space: $FREE”

Simply copy & paste this script into for example into a file named info.sh(create it with VI or JOE or even PICO). Next, you’ll need to make it executable. To do this, use the following command:

# chmod +x info.sh

Now, to execute the file, you need to run it, and pass it the correct argument. For our example, we are going to use hda3. So, to execute the file, type in the command as below….

# ./info.sh hda3

Check on x$bh it show you what objects are in the buffer.

Try this query:

SELECT /*+ ordered use_hash(o) use_hash(bh) */
bp.NAME BUFFER_POOL u.NAME owner so.object_type segment_type
o.NAME segment_name COUNT (*) cached_blocks
FROM v$buffer_pool bp
SYS.seg$ s
SYS.sys_objects so
SYS.obj$ o
SYS.user$ u
x$bh bh
WHERE bh.obj o.dataobj#
AND o.obj# so.object_id
AND o.type# so.object_type_id
AND o.owner# u.user#
AND so.segment_type_id s.type#
AND so.ts_number s.ts#
AND so.header_file s.file#
AND so.header_block s.block#
AND DECODE (s.cachehint 0 3 s.cachehint) bp.ID
GROUP BY u.NAME so.object_type o.NAME bp.NAME
ORDER BY bp.NAME cached_blocks DESC;

DBA_DATAPUMP_JOBS
This view will show the active Data Pump jobs, their state, degree of parallelism, and the number of sessions attached.

DBA_DATAPUMP_SESSIONS
This view gives the SADDR that assist in determining why a Data Pump session may be having problems. Join to the V$SESSION view for further information.

V$SESSION_LONGOPS
This view helps determine how well a Data Pump export is doing. Basically gives you a progress indicator through the MESSAGE column.

By using DBMS_DATAPUMP.metadata_filter, DBMS_DATAPUMP.data_filter we can export a limited number of rows from a table.