[HBASE-10241] implement mvcc-consistent scanners (across recovery)

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Later
• Affects Version/s: 0.99.0
• Component/s: HFile, regionserver, Scanners
• Assignee: Unassigned
• Reporter: Sergey Shelukhin
• Created: 26/Dec/13 18:41
• Updated: 16/Jun/22 18:21
• Resolved: 16/Jun/22 18:21

Description

Scanners currently use mvcc for consistency. However, mvcc is lost on server restart, or even a region move. This JIRA is to enable the scanners to transfer mvcc (or seqId, or some other number, see HBASE-8763) between servers. First, client scanner needs to get and store the readpoint. Second, mvcc needs to be preserved in WAL. Third, the mvcc needs to be stored in store files per KV and discarded when not needed.

Issue Links

• depends upon: HBASE-10227 When a region is opened, its mvcc isn't correctly recovered when there are split hlogs to replay
• is depended upon by: HBASE-9797 Multi row transactions are not atomic for scanners

Sub-Tasks

• client-side mvcc tracking in scanners: Closed
• store mvcc in WAL: Closed
• store mvcc in store files per KV for longer time, discard during compactions based on scanner timeout: Closed