[HBASE-26969] Eliminate MOB renames when SFT is enabled

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.5.0, 3.0.0-alpha-3
• Fix Version/s: 2.5.0, 3.0.0-alpha-4
• Component/s: mob
• Assignee: Szabolcs Bukros
• Reporter: Szabolcs Bukros
• Created: 22/Apr/22 15:10
• Updated: 20/Aug/22 20:12
• Resolved: 19/Aug/22 10:58

Description

MOB file compaction and flush still relies on renames even when SFT is enabled.

My proposed changes are:

• when requireWritingToTmpDirFirst is false during mob flush/compact instead of using the temp writer we should create a different writer using a StoreFileWriterCreationTracker that writes directly to the mob store folder
• these StoreFileWriterCreationTracker should be stored in the MobStore. This would requires us to extend MobStore with a createWriter and a finalizeWriter method to handle this
• refactor MobFileCleanerChore to run on the RS instead on Master to allow access to the StoreFileWriterCreationTrackers to make sure the currently written files are not cleaned up

Issue Links

• is a parent of: HBASE-27154 Backport missing MOB related changes to branch-2
• is blocked by: HBASE-27017 MOB snapshot is broken when FileBased SFT is used
• links to: GitHub Pull Request #4418
• links to: GitHub Pull Request #4712