Thanks for the link to the hive streaming bolt. We rolled our own bolt
many moons ago to utilize hive streaming. We’ve tried it against 0.13 and
0.14 . Acid tables have been a real pain for us. We don’t believe they are
production ready. At least in our use cases, Tez crashes for assorted
reasons or only assigns 1 mapper to the partition. Having delta files and
no base files borks mapper assignments.  Files containing flush in their
name are left scattered about, borking queries. Latency is higher with
streaming than writing to an orc file in hdfs, forcing obscene quantities
of buckets and orc files smaller than any reasonable orc stripe / hdfs
block size. The compactor hangs seemingly at random for no reason we’ve
been able to discern.



An orc file without a footer is junk data (or, at least, the last stripe
is junk data). I suppose my question should have been 'what will the hive
query do when it encounters this? Skip the stripe / file? Error out the
query? Something else?’




Grant Overby
Software Engineer
Cisco.com <http://www.cisco.com/>
grove...@cisco.com
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On 4/14/15, 4:23 PM, "Gopal Vijayaraghavan" <gop...@apache.org> wrote:

>
>> What will Hive do if querying an external table containing orc files
>>that are still being written to?
>
>Doing that directly won¹t work at all. Because ORC files are only readable
>after the Footer is written out, which won¹t be for any open files.
>
>> I won¹t be able to test these scenarios till tomorrow and would like to
>>have some idea of what to expect this afternoon.
>
>If I remember correctly, your previous question was about writing ORC from
>Storm.
>
>If you¹re on a recent version of Storm, I¹d advise you to look at
>storm-hive/ 
>
>https://github.com/apache/storm/tree/master/external/storm-hive
>
>
>Or alternatively, there¹s a ³hortonworks trucking demo² which does a
>partition insert instead.
>
>Cheers,
>Gopal
>
>

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