[HBASE-27532] Add block bytes scanned metrics

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.6.0, 3.0.0-beta-1
• Labels: patch-available
• Release Note: Adds blockBytesScannedCount metrics for the regionserver, table, and operations in JMX. Adds a countOfBlockBytesScanned to ScanMetrics.
• Assignee: Bryan Beaudreault
• Reporter: Bryan Beaudreault
• Created: 13/Dec/22 14:18
• Updated: 05/Dec/23 21:10
• Resolved: 05/Dec/23 21:10

Description

Initially in HBASE-14978, but more recently improved in HBASE-27558 and HBASE-27570, we now track the amount of block bytes scanned by read requests. Random read use-cases (which might read 1 small row from a 64kb block) and heavily filtered scans (which might scan many blocks in order to return a needle in a haystack row) can unknowingly cause RegionServers to do more work than a user expects. Now that we have block IO accounting, we should expose this to the user in the form of jmx metrics and ScanMetrics.

 

Issue Links

• is depended upon by: HBASE-27687 Enhance quotas to consume blockBytesScanned rather than response size
• links to: GitHub Pull Request #5067
• links to: GitHub Pull Request #5146