[HBASE-14576] New HFile version for optimized reverse scans

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Not A Problem
• Assignee: Unassigned
• Reporter: Ben Lau
• Created: 08/Oct/15 00:27
• Updated: 01/Jul/22 21:49
• Resolved: 01/Jul/22 21:49

Description

A new ticket to finish the work from HBASE-14283, which will fix the HFileReader seekBefore() previous block size calculation bug but make the resulting reverse scan take more I/O than a forward scan.

Fixing the bug in the long term requires an HFile version bump, either major or minor. We will put the previous block's size in the HFileBlock header instead of trying to calculate it directly using block offset arithmetic.

Per anoop.hbase's suggestion, I created this ticket so that we can separate the issue of fixing the bug (the responsibility of HBASE-14283) and the issue of getting reverse scans to run quickly (the responsibility of this ticket). It is also unlikely that this ticket will be backported to old versions of HBase eg 0.98 whereas HBASE-14283 can be.

Issue Links

• relates to: HBASE-14283 Reverse scan doesn’t work with HFile inline index/bloom blocks