hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "stack (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-18105) [AMv2] Split/Merge need cleanup; currently they diverge and do not fully embrace AMv2 world
Date Thu, 31 Aug 2017 03:55:02 GMT

    [ https://issues.apache.org/jira/browse/HBASE-18105?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16148406#comment-16148406
] 

stack commented on HBASE-18105:
-------------------------------

bq. ...but still not clear about why this PONR could happen

IIRC, there were holy mary moments where if update to meta failed because hosting server crashed,
then we'd be in an unknown state; the regions had been split but the fact was not recorded
up in hbase:meta.

For AMv2, there is no AMv2 since we will record what step we are at and post-crash will rerun
the step we were at when machine went down (each step is supposed to be idempotent).

You need more [~easyliangjob]? Just say.

> [AMv2] Split/Merge need cleanup; currently they diverge and do not fully embrace AMv2
world
> -------------------------------------------------------------------------------------------
>
>                 Key: HBASE-18105
>                 URL: https://issues.apache.org/jira/browse/HBASE-18105
>             Project: HBase
>          Issue Type: Sub-task
>          Components: Region Assignment
>    Affects Versions: 2.0.0
>            Reporter: stack
>             Fix For: 2.0.0
>
>
> Region Split and Merge work on the new AMv2 but they work differently. This issue is
about bringing them back together and fully embracing the AMv2 program.
> They both have issues mostly the fact that they carry around baggage no longer necessary
in the new world of assignment.
> Here are some of the items:
> Split and Merge metadata modifications are done by the Master now but we have vestige
of Split/Merge on RS still; e.g. when we SPLIT, we ask the Master which asks the RS, which
turns around, and asks the Master to run the operation. Fun. MERGE is all done Master-side.
>  
> Clean this up. Remove asking RS to run SPLIT and remove RegionMergeRequest, etc. on RS-side.
Also remove PONR. We don’t Points-Of-No-Return now we are up on Pv2. Remove all calls in
Interfaces; they are unused. Make RS still able to detect when split, but have it be a client
of Master like anyone else.
> Split is Async but does not return procId
> Split is async. Doesn’t return the procId though. Merge does. Fix. Only hard part here
I think is the Admin API does not allow procid return.
> Flags
> Currently OFFLINE is determined by looking either at the master instance of HTD (isOffline)
and/or at the RegionState#state. Ditto for SPLIT. For MERGE, we rely on RegionState#state.
Related is a note above on how split works -- there is a split flag in HTD when there should
not be.
>  
> TODO is move to rely on RegionState#state exclusively in Master.
> From Split/Merge Procedures need finishing in https://docs.google.com/document/d/1eVKa7FHdeoJ1-9o8yZcOTAQbv0u0bblBlCCzVSIn69g/edit#heading=h.4b60dc1h4m1f



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

Mime
View raw message