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https://issues.apache.org/jira/browse/IMPALA-14138?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18012735#comment-18012735
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ASF subversion and git services commented on IMPALA-14138:
----------------------------------------------------------

Commit 0dd6c154c9f05223768900bff7058b1cdc769c1c in impala's branch 
refs/heads/master from Peter Rozsa
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=0dd6c154c ]

IMPALA-14138: Include generated files in .gitignore

Change-Id: Ie5079c87dd27c2391bee13937d69a3340e2a4fb1
Reviewed-on: http://gerrit.cloudera.org:8080/23223
Reviewed-by: Impala Public Jenkins <[email protected]>
Tested-by: Impala Public Jenkins <[email protected]>


> Detect if filesystem is not co-located in which case we shouldn't collect 
> block location information
> ----------------------------------------------------------------------------------------------------
>
>                 Key: IMPALA-14138
>                 URL: https://issues.apache.org/jira/browse/IMPALA-14138
>             Project: IMPALA
>          Issue Type: Bug
>            Reporter: Zoltán Borók-Nagy
>            Assignee: Zoltán Borók-Nagy
>            Priority: Major
>              Labels: impala-iceberg
>             Fix For: Impala 5.0.0
>
>
> For storage systems that support block location information (HDFS, Ozone) we 
> always retrieve it with the assumption that we can use it for scheduling, to 
> do local reads:
> [https://github.com/apache/impala/blob/master/fe/src/main/java/org/apache/impala/catalog/IcebergFileMetadataLoader.java#L154]
> But it's also typical that Impala is not co-located with the storage system, 
> not even in on-prem deployments. E.g. PVC DS Impala runs in containers, and 
> even if they are co-located, I don't think we try to figure out which 
> container runs on which machine. Also short-circuit reads are off the 
> table.In such cases we should not reach out to the storage system to collect 
> file information because it can be very expensive for large tables and we 
> won't benefit from it at all.
>  
> We could construct the file descriptors based on the information we have in 
> the Iceberg manifests, and this is what we already do on cloud storage 
> systems.
> Is there a good indicator that Impala is not co-located with the configured 
> filesystems? E.g. if data cache is enabled? But of course there could be 
> multiple filesystems configured, some of them co-located, some not..



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