[HBASE-12311] Version stats in HFiles?

• Type: Brainstorming
• Status: Closed
• Priority: Major
• Resolution: Invalid
• Assignee: Unassigned Assign to me
• Reporter: Lars Hofhansl
• Created: 21/Oct/14 17:57
• Updated: 17/Jun/22 17:47
• Resolved: 04/Jul/15 00:06

Description

In HBASE-9778 I basically punted the decision on whether doing repeated scanner.next() called instead of the issueing (re)seeks to the user.
I think we can do better.

One way do that is maintain simple stats of what the maximum number of versions we've seen for any row/col combination and store these in the HFile's metadata (just like the timerange, oldest Put, etc).

Then we estimate fairly accurately whether we have to expect lots of versions (i.e. seek between columns is better) or not (in which case we'd issue repeated next()'s).

Issue Links

• is related to: HBASE-17756 We should have better introspection of HFiles