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https://issues.apache.org/jira/browse/HIVE-11320?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14635223#comment-14635223
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Eugene Koifman commented on HIVE-11320:
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[~alangates], could you review please
> ACID enable predicate pushdown for insert-only delta file
> ---------------------------------------------------------
>
> Key: HIVE-11320
> URL: https://issues.apache.org/jira/browse/HIVE-11320
> Project: Hive
> Issue Type: Bug
> Components: Transactions
> Affects Versions: 1.0.0
> Reporter: Eugene Koifman
> Assignee: Eugene Koifman
> Attachments: HIVE-11320.patch
>
>
> Given ACID table T against which some Insert/Update/Delete has been executed
> but not Major Compaction.
> This table will have some number of delta files. (and possibly base files).
> Given a query: select * from T where c1 = 5;
> OrcRawRecordMerger() c'tor currently disables predicate pushdown in ORC to
> the delta file via eventOptions.searchArgument(null, null);
> When a delta file is known to only have Insert events we can safely push the
> predicate.
> ORC maintains stats in a footer which have counts of insert/update/delete
> events in the file - this can be used to determine that a given delta file
> only has Insert events.
> See OrcRecordUpdate.parseAcidStats()
> This will enable PPD for Streaming Ingest (HIVE-5687) use cases which by
> definition only generate Insert events.
> PPD for deltas with arbitrary types of events can be achieved but it is more
> complicated and will be addressed separately.
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