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https://issues.apache.org/jira/browse/DRILL-7096?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16894701#comment-16894701
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ASF GitHub Bot commented on DRILL-7096:
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arina-ielchiieva commented on issue #1829: DRILL-7096: Develop vector for
canonical Map<K,V>
URL: https://github.com/apache/drill/pull/1829#issuecomment-515761557
@paul-rogers
1. agree regarding naming (it a least must have underscore `true_map`) but
I agree that we need some better naming. canonical_map? Any other suggestions?
2. Support was added for older framework but I agree that for EVF it should
be added as well. Since you knowledge keeper for EVF could you please provide
some guidelines where changes need to be done? Its' still crucial to add
support for older framework since currently only two readers use it (text and
log format) and none of them support maps. This work was done primary for
parquet reader (I am not sure when it will migrate to EVF). So to have maps in
both is reasonable.
3. I see there are unit tests in this PR, maybe not the ones are expected,
could you please expand and give examples which tests do you expect.
4. I believe there are some documentation in the Jiras but I agree that
better java-doc or readme.md should have been provided.
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> Develop vector for canonical Map<K,V>
> -------------------------------------
>
> Key: DRILL-7096
> URL: https://issues.apache.org/jira/browse/DRILL-7096
> Project: Apache Drill
> Issue Type: Sub-task
> Reporter: Igor Guzenko
> Assignee: Bohdan Kazydub
> Priority: Major
> Fix For: 1.17.0
>
>
> Canonical Map<K,V> datatype can be represented using combination of three
> value vectors:
> keysVector - vector for storing keys of each map
> valuesVector - vector for storing values of each map
> offsetsVector - vector for storing of start indexes of next each map
> So it's not very hard to create such Map vector, but there is a major issue
> with such map representation. It's hard to search maps values by key in such
> vector, need to investigate some advanced techniques to make such search
> efficient. Or find other more suitable options to represent map datatype in
> world of vectors.
> After question about maps, Apache Arrow developers responded that for Java
> they don't have real Map vector, for now they just have logical Map type
> definition where they define Map like: List< Struct<key:key_type,
> value:value_type> >. So implementation of value vector would be useful for
> Arrow too.
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