Old Obsolete Backup is not Deleted

Hi,

Happy new year (after almost a month). I was quite busy and lazy to write a new blog post but today I found the energy.

What I realized newly is a little bit shocking for me because I had no idea! Maybe this is just an ignorance of me but I never read anything about this (I had read entire backup and recovery documentation of oracle) and never heard of it. Here is the problem: “Report Obsolete”  or “Delete Obsolete” commands don’t report or delete an old backup even if it is beyond the retention period.

At first, I thought probably I am missing something about retention period or maybe a datafile is not backed up correctly (which is not much a possibility). After debugging RMAN report obsolete command, some debug logs takes my attention and I think I found the issue but have no idea whether this is a bug or a feature. I will demonstrate it with a single non-cdb database instance to keep things easy. This is a 19.16 database in a virtual machine and this is happening in both Linux and windows. an empty database, here is the schema report:

Let’s create a dummy tablespace first:

Database has no backup at all at that point, Let’s get one:

our new test tablespace TBS_TEST is backup up along with the database. Now, my retention period is default which is REDUNDANCY 1:

that means only 1 last backup for everything (database, tablespace, datafile) is enough and all previous backups are “obsolete”. Now before getting a second backup let’s delete TBS_TEST tablespace:

and get a new backup:

Good, I have two backups now and TBS_TEST is not included on the last one. since my retention policy is “REDUNDANCY 1”, previous backup should be “obsolete”. List backups:

as you see datafile 5 row in the first backup has no Datafile Name anymore because it is dropped. Now, lets report obsolete backups:

Huh! Only autobackup is obsolete and report command doesn’t mention about previous backup! Please remember my retention is redundancy 1 so only last backup should be kept but RMAN is keeping previous backup, the one with dropped tablespace/datafile.

if I keep taking new backups and run report obsolete (or delete obsolete) commands, it doesn’t report the first backup, only the ones after that.

I tried this with a 19.3 databases and it didn’t happen! it marked old backup as obsolete immediately. So as I said, I don’t know if this is my ignorance, lack of knowledge of just missing something or a bug but on different systems (on virtual machines, linux and windows servers) for 19.16, I see this behavior.  Also, it could be a Container database or a non-cdb. You might want to check your systems if there are older backups than your retention periods.

Thanks for reading, wish you all a happy, healthy new year. My next post will be about a ORA-00600 which drives me crazy for a few weeks.

EDIT: I should add one more thing, by the retention policy requirements all archivelogs between old “obsolete” backup and the current one are deleted! so, this old backup file is completely useless.