[jira] [Created] (HBASE-30389) Normalize region locations when loading state after master failover

["huginn (Jira)" <ji...@apache.org>]

huginn created HBASE-30389:
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             Summary: Normalize region locations when loading state after master failover
                 Key: HBASE-30389
                 URL: https://issues.apache.org/jira/browse/HBASE-30389
             Project: HBase
          Issue Type: Bug
          Components: master
    Affects Versions: 2.4.11
            Reporter: huginn
            Assignee: huginn


h2. What happens

After an active master failover, a region in a non-online state can retain an old region server in the new master's in-memory region location.

h2. When it happens

This can occur when the active master rebuilds assignment state from hbase:meta and the row still contains stale location columns for a region whose persisted state is not one of OPEN, OPENING, CLOSING, SPLITTING, or MERGING.

h2. Impact

The new master can expose stale region ownership that is inconsistent with its per-server assignment state, which can affect assignment-related decisions and status reporting.

h2. Root cause

AssignmentManager.RegionMetaLoadingVisitor.visitRegionState unconditionally copies the location read from hbase:meta into RegionStateNode, but only current-host states are added to a ServerStateNode. For CLOSED and other non-online states, a stale location can therefore remain in memory even though the region is not assigned to that server.

See [AssignmentManager.java on community master|https://github.com/apache/hbase/blob/master/hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignmentManager.java#L1865-L1889].

h2. Proposed fix

Normalize the loaded location to null for states that do not have current-host semantics, while preserving lastHost for locality and recovery. Keep locations for online and transitioning states unchanged, and add regression coverage for master failover and state loading.

h2. Reproduction / Testing

Testing evidence will be added by the reporter.



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