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https://issues.apache.org/jira/browse/HIVE-19985?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16564509#comment-16564509
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Eugene Koifman commented on HIVE-19985:
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LLAP notes:
{{OrcEncodedDataReader}} does {{fileIncludes =
includes.generateFileIncludes(fileSchema);}}
{{LlapRecordReader.next()}} gets a {{ColumnVectorBatch}} and wraps it in
{{AcidWrapper}} and does
{{VectorizedOrcAcidRowBatchReader.setBaseAndInnerReader()}} then calls next()
on acid reader
Acid reader is created from {{LlapRecordReader}} c'tor
> ACID: Skip decoding the ROW__ID sections for read-only queries
> ---------------------------------------------------------------
>
> Key: HIVE-19985
> URL: https://issues.apache.org/jira/browse/HIVE-19985
> Project: Hive
> Issue Type: Improvement
> Components: Transactions
> Reporter: Gopal V
> Assignee: Eugene Koifman
> Priority: Major
> Labels: Branch3Candidate
> Attachments: HIVE-19985.01.patch
>
>
> For a base_n file there are no aborted transactions within the file and if
> there are no pending delete deltas, the entire ACID ROW__ID can be skipped
> for all read-only queries (i.e SELECT), though it still needs to be projected
> out for MERGE, UPDATE and DELETE queries.
> This patch tries to entirely ignore the ACID ROW__ID fields for all tables
> where there are no possible deletes or aborted transactions for an ACID split.
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