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https://issues.apache.org/jira/browse/HIVE-30227?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Denys Kuzmenko updated HIVE-30227:
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Issue Type: Bug (was: Improvement)
> Iceberg: a V3 materialized view rebuild in insert-delete mode writes two DVs
> per data file
> ------------------------------------------------------------------------------------------
>
> Key: HIVE-30227
> URL: https://issues.apache.org/jira/browse/HIVE-30227
> Project: Hive
> Issue Type: Bug
> Reporter: Denys Kuzmenko
> Priority: Major
>
> An incremental rebuild of a materialized view in insert-delete mode
> (AGGREGATE_INSERT_DELETE_REBUILD: a V3 Iceberg materialized view with
> count(*) over full-ACID sources) has two DELETE branches into the view: one
> for the groups it updates and one for the groups whose count drops to 0. Each
> branch gets its own DISTRIBUTE BY FILE__PATH, reducer and DV writer, so a
> data file holding rows of both gets two DVs in one commit, which Iceberg then
> merges at commit time (merged-dvs). HIVE-30112 made every other merge-on-read
> DML write one DV per data file.
> *Fix*
> Combine the two delete branches of the rebuild into one, as
> SplitMergeRewriter does for a MERGE with UPDATE and DELETE clauses
> (AlterMaterializedViewRebuildAnalyzer: the two DestClausePrefix.DELETE
> branches).
> Found in the review of HIVE-30112.
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