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https://issues.apache.org/jira/browse/HIVE-16812?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16628015#comment-16628015
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Eugene Koifman commented on HIVE-16812:
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patch 5 should be ready for review
VectorizedOrcAcidRowBatchReader examines the split worth of insert events and
based on that generates 2 sets of bounds to use to filter delete events before
loading them into in-memory structure.
The 1st set is min/max ROW__ID.
The 2nd is a SARG to push down to delete_delta files
This is used by ColumnizedDeleteEventRegistry but not
SortMergedDeleteEventRegistry.
A limitation is that it currently doesn't handle {{OrcSplit.isOriginal()}}
files. This should be done in a followup after HIVE-17917.
[~gopalv] could you review please
> VectorizedOrcAcidRowBatchReader doesn't filter delete events
> ------------------------------------------------------------
>
> Key: HIVE-16812
> URL: https://issues.apache.org/jira/browse/HIVE-16812
> Project: Hive
> Issue Type: Improvement
> Components: Transactions
> Affects Versions: 2.3.0
> Reporter: Eugene Koifman
> Assignee: Eugene Koifman
> Priority: Critical
> Attachments: HIVE-16812.02.patch, HIVE-16812.04.patch,
> HIVE-16812.05.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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