You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues-all@impala.apache.org by "Zoltán Borók-Nagy (Jira)" <ji...@apache.org> on 2024/01/29 15:38:00 UTC
[jira] [Assigned] (IMPALA-12765) Balance consecutive partitions better for Iceberg tables
[ https://issues.apache.org/jira/browse/IMPALA-12765?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Zoltán Borók-Nagy reassigned IMPALA-12765:
------------------------------------------
Assignee: Zoltán Borók-Nagy
> Balance consecutive partitions better for Iceberg tables
> --------------------------------------------------------
>
> Key: IMPALA-12765
> URL: https://issues.apache.org/jira/browse/IMPALA-12765
> Project: IMPALA
> Issue Type: Bug
> Components: Frontend
> Reporter: Zoltán Borók-Nagy
> Assignee: Zoltán Borók-Nagy
> Priority: Major
> Labels: impala-iceberg
>
> During scheduling Impala does the following:
> * Non-Iceberg tables
> ** The scheduler processes the scan ranges in partition key order
> ** The scheduler selects N replicas as candidates
> ** The scheduler chooses the executor from the candidates based on minimum number of assigned bytes
> ** So consecutive partitions are more likely to be assigned to different executors
> * Iceberg tables
> ** The scheduler processes the scan ranges in random order
> ** The scheduler selects N replicas as candidates
> ** The scheduler chooses the executor from the candidates based on minimum number of assigned bytes
> ** So consecutive partitions (by partition key order) are assigned randomly, i.e. there's a higher chances of clustering
> If the IcebergScanNode ordered its file descriptors based on their paths we would have a more balanced scheduling for consecutive partitions. Queries that operate on a range of partitions are quite common, so it makes sense to optimize that case.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-all-unsubscribe@impala.apache.org
For additional commands, e-mail: issues-all-help@impala.apache.org