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https://issues.apache.org/jira/browse/DRILL-7096?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16914161#comment-16914161
]
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_r317076122
##########
File path:
exec/java-exec/src/main/java/org/apache/drill/exec/store/parquet/metadata/Metadata_V4.java
##########
@@ -400,11 +405,23 @@ public Object deserializeKey(String key,
com.fasterxml.jackson.databind.Deserial
* Note: Since the structure of column metadata hasn't changes from v3,
ColumnMetadata_v4 extends ColumnMetadata_v3
*/
public static class ColumnMetadata_v4 extends Metadata_V3.ColumnMetadata_v3 {
+
+ List<OriginalType> originalTypes;
+
public ColumnMetadata_v4() {
}
public ColumnMetadata_v4(String[] name, PrimitiveType.PrimitiveTypeName
primitiveType, Object minValue, Object maxValue, Long nulls) {
+ this(name, primitiveType, minValue, maxValue, nulls, new ArrayList<>());
+ }
+
+ public ColumnMetadata_v4(String[] name, PrimitiveType.PrimitiveTypeName
primitiveType, Object minValue, Object maxValue, Long nulls, List<OriginalType>
originalTypes) {
super(name, primitiveType, minValue, maxValue, nulls);
+ this.originalTypes = Collections.unmodifiableList(originalTypes);
Review comment:
`this.parentTypes = new ArrayList<>(parentTypes);` you wrap into list, here
you wrap in unmodifiable... looks like different approach for similar cases...
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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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