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https://issues.apache.org/jira/browse/IMPALA-14138?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Quanlong Huang resolved IMPALA-14138.
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Fix Version/s: Impala 5.0.0
Resolution: Fixed
Resolving this. Now this is configurable. Auto-detecting whether Impala should
skip collecting block locations can be done in a follow-up JIRA.
> 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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