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From "Adam J. Shook" <adamjsh...@gmail.com>
Subject Re: Status record lacked createdTime
Date Fri, 17 Feb 2017 18:58:32 GMT
No exception on write -- this is coming from the master when it goes to
assign work to the accumulo.replication table.  Some of the WALs are fairly
old.

Not too sure why it didn't get the attribute; my guess is server failure
before it was able to append the created time.  Some of the WAL files are
empty, others have data in them.  I think a tool will suffice for now when
the issue crops up, but it'll need to get fixed in the Master/GC so that,
after some condition, it will assign it a createdTime so replication will
occur -- or whenever the first metadata entry is added, give it a
createdTime.

--Adam

On Fri, Feb 17, 2017 at 1:40 PM, Josh Elser <josh.elser@gmail.com> wrote:

> Hey Adam,
>
> Thanks for sharing this one.
>
> Adam J. Shook wrote:
>
>> Hello folks,
>>
>> One of our clusters has been throwing a handful of replication errors
>> from the status maker -- see below.  The WAL files in question to not
>> belong to an active tserver -- some investigation in the code shows that
>> the createdTime could not be written and these WALs will sit here until
>> a created time is added.
>>
>
> Does that mean that you saw an exception when the mutation written to
> accumulo.metadata that had the createTime failed? Or is the cause of why
> that WAL didn't get this 'attribute' still unknown?
>
> I think the kind of fix to make it dependent on the cause here. e.g. if
> this is just a bug, a standalone tool to fix this case would be good.
> However, if there's an inherent issue where this case might happen and we
> can't guarantee the record was written (server failure), it might be best
> to add some process to the master/gc to eventually add one (e.g. if we see
> the wal has been hanging out in the state, add a createdTime after ~12hrs)
>
>
> I wanted to bring some attention to this -- I think my immediate course
>> of action here is to manually add a createdTime so the files will be
>> replicated, then address this within the Accumulo source code itself.
>> Thoughts?
>>
>> Status record ([begin: 0 end: 0 infiniteEnd: true closed:true]) for
>> hdfs://foo:8020/accumulo/wal/blah/blah in table k was written to
>> metadata table which lacked createtime
>>
>> Thank you,
>> --Adam
>>
>

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