[HBASE-26649] Support meta replica LoadBalance mode for RegionLocator#getAllRegionLocations()

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.9
• Fix Version/s: 2.5.0, 3.0.0-alpha-3, 2.4.13
• Component/s: meta replicas

Release Note

When setting 'hbase.locator.meta.replicas.mode' to "LoadBalance" at HBase client, RegionLocator#getAllRegionLocations() now load balances across all Meta Replica Regions. Please note, results from non-primary meta replica regions may contain stale data.

• Assignee: Huaxiang Sun
• Reporter: Huaxiang Sun
• Created: 06/Jan/22 21:56
• Updated: 05/Jun/22 05:36
• Resolved: 03/Jun/22 22:45

Description

When HBase application restarts, its meta cache is empty. Normally, it will fill the meta cache one region at a time by scanning the meta region. This will cause huge pressure to the region server hosting meta during application restart. 

It can prefetching all region locations by calling RegionLocator#getAllRegionLocations().Meta replica LoadBalance mode is support in 2.4, it will be nice to load balance RegionLocator#getAllRegionLocations() to all meta replica regions so batch scan can spread across all meta replica regions.

Issue Links

• is part of: HBASE-18070 Enable memstore replication for meta replica
• links to: GitHub Pull Request #4044
• links to: GitHub Pull Request #4078
• links to: GitHub Pull Request #4442
• links to: GitHub Pull Request #4464
• links to: GitHub Pull Request #4484
• links to: GitHub Pull Request #4485