[jira] [Resolved] (HBASE-30350) Stale entry left in RegionInTransitionTracker after GCRegionProcedure purges region metadata

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

     [ https://issues.apache.org/jira/browse/HBASE-30350?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Aman Poonia resolved HBASE-30350.
---------------------------------
    Resolution: Duplicate

> Stale entry left in RegionInTransitionTracker after GCRegionProcedure purges region metadata
> --------------------------------------------------------------------------------------------
>
>                 Key: HBASE-30350
>                 URL: https://issues.apache.org/jira/browse/HBASE-30350
>             Project: HBase
>          Issue Type: Bug
>          Components: master, Region Assignment
>    Affects Versions: 3.0.0, 4.0.0-alpha-1, 2.5.16, 2.6.7
>            Reporter: Aman Poonia
>            Assignee: Aman Poonia
>            Priority: Major
>              Labels: pull-request-available
>
> GCRegionProcedure (state {{GC_REGION_PURGE_METADATA}}) removes a GC'd split/merged parent region from {{AssignmentManager#regionStates}} but never removes the corresponding entry from the separate
>   {{RegionInTransitionTracker}} map. These two maps are not kept in sync automatically.
>   The analogous cleanup path, {{AssignmentManager#markRegionAsMerged}}, correctly calls both {{regionStates.deleteRegion(ri)}} and {{regionInTransitionTracker.handleRegionDelete(ri)}} for each merge
>   parent. {{GCRegionProcedure}} only calls the former.
>   As a result, once a region is GC'd via {{CatalogJanitor}} -> {{GCRegionProcedure}}, its ghost entry remains in {{RegionInTransitionTracker}} indefinitely. The periodic "STUCK Region-In-Transition"
>   chore ({{ProcExecTimeout}} thread) keeps re-reporting this already-deleted region as stuck on every run, producing misleading WARN logs and inflating RIT-age metrics/alerts. The stale entry is only
>   cleared when the active master fails over, since {{AssignmentManager#joinCluster}} -> {{loadMeta}} rebuilds all in-memory assignment state fresh from {{hbase:meta}}.
>   *Observed in production:* a region was GC'd (fully removed from {{hbase:meta}} and HDFS) but continued to be logged as "STUCK Region-In-Transition" for ~9 hours until the next master failover
>   silently cleared it, giving a false impression of an actual 9-hour stuck RIT / unavailability.
>   *Fix:* add a shared {{AssignmentManager#deleteRegion(RegionInfo)}} method that removes the region from both {{regionStates}} and {{regionInTransitionTracker}} together, and have both
>   {{markRegionAsMerged}} and {{GCRegionProcedure}} call it instead of touching {{regionStates}} directly.
>   Confirmed present on {{apache/master}} as of commit fb4286d3046.



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