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From "Eugene Koifman (JIRA)" <>
Subject [jira] [Resolved] (HIVE-16812) VectorizedOrcAcidRowBatchReader doesn't filter delete events
Date Thu, 27 Sep 2018 20:29:00 GMT


Eugene Koifman resolved HIVE-16812.
      Resolution: Fixed
    Release Note: n/a

committed to master
thanks Sergey for the review

> VectorizedOrcAcidRowBatchReader doesn't filter delete events
> ------------------------------------------------------------
>                 Key: HIVE-16812
>                 URL:
>             Project: Hive
>          Issue Type: Improvement
>          Components: Transactions
>    Affects Versions: 2.3.0
>            Reporter: Eugene Koifman
>            Assignee: Eugene Koifman
>            Priority: Critical
>             Fix For: 4.0.0
>         Attachments: HIVE-16812.02.patch, HIVE-16812.04.patch, HIVE-16812.05.patch, HIVE-16812.06.patch,
> the c'tor of VectorizedOrcAcidRowBatchReader has
> {noformat}
>     // Clone readerOptions for deleteEvents.
>     Reader.Options deleteEventReaderOptions = readerOptions.clone();
>     // Set the range on the deleteEventReaderOptions to 0 to INTEGER_MAX because
>     // we always want to read all the delete delta files.
>     deleteEventReaderOptions.range(0, Long.MAX_VALUE);
> {noformat}
> This is suboptimal since base and deltas are sorted by ROW__ID.  So for each split if
base we can find min/max ROW_ID and only load events from delta that are in [min,max] range.
 This will reduce the number of delete events we load in memory (to no more than there in
the split).
> When we support sorting on PK, the same should apply but we'd need to make sure to store
PKs in ORC index
> See {{OrcRawRecordMerger.discoverKeyBounds()}}
> {{hive.acid.key.index}} in Orc footer has an index of ROW__IDs so we should know min/max
easily for any file written by {{OrcRecordUpdater}}

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