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https://issues.apache.org/jira/browse/DRILL-7096?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16914155#comment-16914155
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ASF GitHub Bot commented on DRILL-7096:
---------------------------------------
arina-ielchiieva commented on pull request #1829: DRILL-7096: Develop vector
for canonical Map<K,V>
URL: https://github.com/apache/drill/pull/1829#discussion_r317073940
##########
File path:
exec/java-exec/src/main/java/org/apache/drill/exec/store/parquet/ParquetRecordWriter.java
##########
@@ -85,6 +84,22 @@
private static final int MAXIMUM_RECORD_COUNT_FOR_CHECK = 10000;
private static final int BLOCKSIZE_MULTIPLE = 64 * 1024;
+ /**
+ * Name of nested group for Parquet's {@code MAP} type.
+ * @see <a
href="https://github.com/apache/parquet-format/blob/master/LogicalTypes.md#maps";>MAP
logical type</a>
+ */
+ private static final String GROUP_KEY_VALUE_NAME = "key_value";
+ /**
+ * Name of nested group for Parquet's {@code LIST} type.
+ * @see <a
href="https://github.com/apache/parquet-format/blob/master/LogicalTypes.md#lists";>LIST
logical type</a>
+ */
+ private static final String GROUP_LIST_NAME = "list";
Review comment:
Recently Igor was adding similar constants in
https://github.com/apache/drill/pull/1844, please revisit.
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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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