[HBASE-4536] Allow CF to retain deleted rows

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.92.0
• Fix Version/s: 0.94.0
• Component/s: regionserver
• Hadoop Flags: Reviewed
• Assignee: Lars Hofhansl
• Reporter: Lars Hofhansl
• Created: 03/Oct/11 23:10
• Updated: 12/Oct/12 05:34
• Resolved: 21/Oct/11 19:55

Description

Parent allows for a cluster to retain rows for a TTL or keep a minimum number of versions.
However, if a client deletes a row all version older than the delete tomb stone will be remove at the next major compaction (and even at memstore flush - see HBASE-4241).
There should be a way to retain those version to guard against software error.

I see two options here:
1. Add a new flag HColumnDescriptor. Something like "RETAIN_DELETED".
2. Folds this into the parent change. I.e. keep minimum-number-of-versions of versions even past the delete marker.

#1 would allow for more flexibility. #2 comes somewhat naturally with parent (from a user viewpoint)

Comments? Any other options?

Issue Links

• duplicates: HBASE-848 API to inspect cell deletions
• relates to: HBASE-3443 ICV optimization to look in memstore first and then store files (HBASE-3082) does not work when deletes are in the mix
• relates to: HBASE-2376 Add special SnapshotScanner which presents view of all data at some time in the past
• relates to: HBASE-4721 Retain Delete Markers after Major Compaction