[jira] [Resolved] (HBASE-30433) Seed the master's flushedSequenceIdByRegion watermark with the region's final flushed seqid on region CLOSE

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

     [ https://issues.apache.org/jira/browse/HBASE-30433?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Viraj Jasani resolved HBASE-30433.
----------------------------------
    Fix Version/s: 4.0.0-alpha-1
                   2.7.0
                   3.1.0
                   3.0.1
                   2.6.8
     Hadoop Flags: Reviewed
       Resolution: Fixed

> Seed the master's flushedSequenceIdByRegion watermark with the region's final flushed seqid on region CLOSE
> -----------------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-30433
>                 URL: https://issues.apache.org/jira/browse/HBASE-30433
>             Project: HBase
>          Issue Type: Bug
>          Components: proc-v2
>    Affects Versions: 3.0.0, 2.6.5, 2.6.7
>            Reporter: Nirdosh Kumar Yadav
>            Assignee: Nirdosh Kumar Yadav
>            Priority: Minor
>              Labels: pull-request-available
>             Fix For: 4.0.0-alpha-1, 2.7.0, 3.1.0, 3.0.1, 2.6.8
>
>
> Summary — HBASE-30335 seeds the master's flushedSequenceIdByRegion watermark with openSeqNum at OPEN time so a later WAL split of a drained/crashed source RS recognizes already-durable edits instead of writing orphaned recovered.edits. This follow-up additionally seeds the same watermark at CLOSE time, using the region's final flushed seqid, to tighten a narrow window the OPEN-time seed alone doesn't cover.
> Motivation (window flagged by [~Umeshkumar9414] on #8584):
> 1. A region is gracefully closed on the source RS (memstore flushed to the close marker).
> 2. The source RS dies before the target RS finishes OPEN — so the OPEN-time seed hasn't fired.
> 3. The source RS's SCP splits its WAL in that window, filtering against the still-stale watermark, and writes a (harmless-but-present) recovered.edits file.
> Seeding on CLOSE advances the watermark to the reported flushed seqid before the source RS dies. It's additive, not a replacement: it does nothing for the pure-crash / never-gracefully-closed path, so the OPEN-time seed must remain. Both writers use the same monotonic merge(Math::max), so they compose safely.
> Proposed change (no proto/RPC change — the RegionStateTransition message already carries optional openSeqNum, and CLOSED is already routed through the same master handler):
> - RegionServer — CloseRegionHandler / UnassignRegionHandler pass HRegion.getMaxFlushedSeqId() instead of NO_SEQNUM; HRegionServer.createReportRegionStateTransitionRequest sets the wire openSeqNum field for CLOSED too (when >= 0).
> - Master — AssignmentManager CLOSED case seeds via serverManager.reportRegionOpen(regionInfo, seqId).



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