[HBASE-28715] Backup delete incorrectly handles bulk loaded entries

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.6.0, 3.0.0, 4.0.0-alpha-1
• Component/s: backup&restore
• Assignee: Unassigned
• Reporter: Dieter De Paepe
• Created: 08/Jul/24 12:12
• Updated: 08/Jul/24 12:12

Description

To delete a backup, `BackupAdminImpl#deleteBackup` calls `BackupSystemTable#deleteBulkLoadedRows` on all rows returned by `BackupSystemTable#readBulkLoadedFiles(backupId)`.

This last method comes down to a scan over the bulk load table for all rows matching "bulk:BACKUPID:".

However, current code never writes rows of that format. The only methods that do so are `BackupSystemTable#writeBulkLoadedFiles` and `BackupSystemTable#createPutForBulkLoadedFile`, which are only used in test code.

Note that the bulkload rows that do get written (see `BackupObserver`) only get deleted when creating incremental backups, but suffer from HBASE-28706.

Consequences: I suspect that if you do some bulk loads, create a full backup, and delete that backup before doing any incremental backup, those entries in the bulk load table will never get deleted, meaning those HFiles can never get deleted (because `BackupLogCleaner` blocks their deletion).