[HBASE-28334] Add comment around erasure coding policy in DEFAULT_VALUE map

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.6.0, 3.0.0-beta-2
• Labels: pull-request-available
• Assignee: Nirdosh Kumar Yadav
• Reporter: Bryan Beaudreault
• Created: 29/Jan/24 14:40
• Updated: 06/Feb/24 20:46
• Resolved: 05/Feb/24 13:22

Description

New description: Upon investigation, we realized that it's necessary to put ERASURE_CODING_POLICY in the DEFAULT_VALUES map so that when the TableDescriptor is printed as a string, that setting is not listed as METADATA. We added a comment to note that for future reference.

Old description: With ERASURE_CODING_POLICY, the default value is null (no policy). I added a record of that in DEFAULT_VALUES, because other settings seemed to do that.

A null value is never stored on a HTD because our code handles removing from map when setting null. So we'd never have an opportunity to match against the DEFAULT_VALUE. If someone tried setting a string value "null", that would fail validation because it's not a valid policy. So there's no reason to record this default value. It doesn't cause a problem, but is confusing to anyone reading the code. Remove it.

Issue Links

• links to: GitHub Pull Request #5662