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https://issues.apache.org/jira/browse/DRILL-3827?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vitalii Diravka reassigned DRILL-3827:
--------------------------------------

    Assignee: Vitalii Diravka  (was: Parth Chandra)

> Empty metadata file causes queries on the table to fail
> -------------------------------------------------------
>
>                 Key: DRILL-3827
>                 URL: https://issues.apache.org/jira/browse/DRILL-3827
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Query Planning & Optimization
>    Affects Versions: 1.2.0
>            Reporter: Victoria Markman
>            Assignee: Vitalii Diravka
>            Priority: Critical
>             Fix For: Future
>
>
> I ran into a situation where drill created an empty metadata file (which is a 
> separate issue and I will try to narrow it down. Suspicion is that this 
> happens when "refresh table metada x" fails with "permission denied" error).
> However, we need to guard against situation where metadata file is empty or 
> corrupted. We probably should skip reading it if we encounter unexpected 
> result and continue with query planning without that information. In the same 
> fashion as partition pruning failure. It's also important to log this 
> information somewhere, drillbit.log as a start. It would be really nice to 
> have a flag in the query profile that tells a user if we used metadata file 
> for planning or not. Will help in debugging performance issues.
> Very confusing exception is thrown if you have zero length meta data file in 
> the directory:
> {code}
> [Wed Sep 23 07:45:28] # ls -la
> total 2
> drwxr-xr-x  2 root root   2 Sep 10 14:55 .
> drwxr-xr-x 16 root root  35 Sep 15 12:54 ..
> -rwxr-xr-x  1 root root 483 Jul  1 11:29 0_0_0.parquet
> -rwxr-xr-x  1 root root   0 Sep 10 14:55 .drill.parquet_metadata
> 0: jdbc:drill:schema=dfs> select * from t1;
> Error: SYSTEM ERROR: JsonMappingException: No content to map due to 
> end-of-input
>  at [Source: com.mapr.fs.MapRFsDataInputStream@342bd88d; line: 1, column: 1]
> [Error Id: c97574f6-b3e8-4183-8557-c30df6ca675f on atsqa4-133.qa.lab:31010] 
> (state=,code=0)
> {code}
> Workaround is trivial, remove the file. Marking it as critical, since we 
> don't have any concurrency control in place and this file can get corrupted 
> as well.



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