RMAN Duplicate issue

Hi all,

          I have an interesting issue with RMAN Duplicate process. Following is the scenario i have

1. I have a FULL Incremental Level 0 backup plus archive log of date *March 10th*.
2. I have taken a new FULL incremental Level 0 backup plus archive log today i.e.,* March 18th*.

Following is the backup script i have used to take backups:

*run*
*{*
*allocate channel c1 device type disk format '$HOME/testdb1_%s_%t_%U';*
*allocate channel c2 device type disk format '$HOME/testdb1_%s_%t_%U';*
*backup as compressed backupset incremental level 0 database plus
archivelog;*
*backup current controlfile format '$HOME/testdb1contro.ctl';*
*}*
**

Now, from the recent FULL backup (plus archivelog) of March 18th, the last * SEQUENCE* of archive log in the archivelog backupset is *1445*.

Scenarios: I am Duplicating TESTDB1 to TESTDB2 on new host by setting the * SEQUENCE* clause in Duplicate script.

*1.* The Duplication works absolutely fine when i set the SEQUENCE to *1446

• (i.e., a number more than the maximum sequence *1445* in the backupset). When i set this, the RMAN is taking the most recent backup i.e., of March18th and performing the dupication, which is as expected. Following is the script i have used:

*connect **target=sys/sys_at_TESTDB1* <target=sys/sys_at_TESTDB1>
*connect auxiliary /*
*run *
*{*
*allocate auxiliary channel c1 device type disk;*
*allocate auxiliary channel c2 device type disk;*
*set until sequence 1446 thread 1;*
*duplicate target database to TESTDB2;*
*}*

*2. *The real-problem occurs here. When i try to DUPLICATE the database by
setting the *SEQUENCE* to *1445*, the DUPLICATION is failing. The reason when i looked into the RMAN log was that RMAN started looking into the older backups (i.e, of March 10th) rather than the most recent FULL backup that we have in place. Even though i had everything in place, it failed with ORA -279 errors. Following is the DUPLICATE script:

 *connect **target=sys/sys_at_TESTDB1* <target=sys/sys_at_TESTDB1>
*connect auxiliary /*
*run *
*{*
*allocate auxiliary channel c1 device type disk;*
*allocate auxiliary channel c2 device type disk;*
*set until sequence 1445 thread 1;*
*duplicate target database to TESTDB2;*
*}*
**

My question here is,

1. Why is RMAN looking into older backups when we set the UNTIL SEQUENCE to the value present in archivelog backupset?
2. RMAN always starts looking from the most recent backups whenever a restore and recovery is performed. When i do have a most recent FULL plus archivelog backup of the database, why in this case has RMAN started looking from the older backups?

I have even the tried DUPLICATION process by deleting the March 10th backup (ofcourse, i have run crosscheck) and having only March 18th backup on disk. In this case, when i set the UNTIL SEQUENCE to 1445, the duplication failed at the first step itself, i.e, at the restore, saying that there are no backups of data file number available, where the truth is i do have most recent FULL backup on disk.

Any info will be of great help.

THanks,
Godwin.

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