[HBASE-13984] Add option to allow caller to know the heartbeat and scanner position when scanner timeout

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Abandoned
• Component/s: Scanners
• Assignee: Unassigned
• Reporter: He Liangliang
• Created: 29/Jun/15 03:01
• Updated: 23/Jun/22 20:43
• Resolved: 11/Jun/22 19:39

Description

HBASE-13090 introduced scanner heartbeat. However, there are still some limitations (see HBASE-13215). In some application, for example, an operation access hbase to scan table data, and there is strict limit that this call must return in a fixed interval. At the same time, this call is stateless, so the call must return the next position to continue the scan. This is typical use case for online applications.

Based on this requirement, some improvements are proposed:
1. Allow client set a flag whether pass the heartbeat (a result contains the scanner position) to the caller (via ResultScanner next)
2. Allow the client pass a timeout to the server, which can override the server side default value
3. When requested by the client, the server peek the next cell and return to the client in the heartbeat message

Issue Links

• duplicates: HBASE-13215 A limit on the raw key values is needed for each next call of a scanner