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Posted to dev@hive.apache.org by Ashish Singh <as...@gmail.com> on 2016/07/15 01:24:24 UTC

One Mapper runs in ACID tables

Hi Team,

I have created ACID tables in Hive , while executing queries found a very
unusual behavior
Only one mapper runs if we have only delta files and in order to optimize
it we have to run major compactions to merge to base files

Want to confirm why we  have implemented it in this way and if any
correction in understanding is required please update






Thanks,
Ashish  Singh

Re: One Mapper runs in ACID tables

Posted by Gopal Vijayaraghavan <go...@apache.org>.


>Want to confirm why we  have implemented it in this way and if any
>correction in understanding is required please update

This is not implemented intentionally - the issue is that delta files show
up as 0 sized splits.

You should be getting exactly as many splits as you have buckets x
partitions in Hive-2.0.

This fix can't be backported to hive-1.2.1 without a corresponding Tez
upgrade to 0.7.x.

<https://github.com/apache/hive/commit/76961d1f67a5d5e3614d3d81c417684fab92
c6c2>


Cheers,
Gopal