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https://issues.apache.org/jira/browse/DRILL-7313?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16877719#comment-16877719
]
ASF GitHub Bot commented on DRILL-7313:
---------------------------------------
arina-ielchiieva commented on pull request #1819: DRILL-7313: Use Hive schema
for MaprDB native reader when field was empty
URL: https://github.com/apache/drill/pull/1819#discussion_r299881301
##########
File path:
exec/java-exec/src/main/java/org/apache/drill/exec/vector/complex/fn/JsonReaderUtils.java
##########
@@ -33,25 +38,48 @@ public static void
ensureAtLeastOneField(BaseWriter.ComplexWriter writer,
boolean allTextMode,
List<BaseWriter.ListWriter>
emptyArrayWriters) {
- List<BaseWriter.MapWriter> writerList = Lists.newArrayList();
- List<PathSegment> fieldPathList = Lists.newArrayList();
+ ensureAtLeastOneField(writer, columns, null /* schema */, allTextMode,
emptyArrayWriters);
+ }
+
+ public static void ensureAtLeastOneField(BaseWriter.ComplexWriter writer,
+ Collection<SchemaPath> columns,
+ TupleMetadata schema,
+ boolean allTextMode,
+ List<BaseWriter.ListWriter>
emptyArrayWriters) {
+
+ List<BaseWriter.MapWriter> writerList = new ArrayList<>();
+ List<PathSegment> fieldPathList = new ArrayList<>();
+ List<TypeProtos.MajorType> types = new ArrayList<>();
BitSet emptyStatus = new BitSet(columns.size());
- int i = 0;
+ int fieldIndex = 0;
// first pass: collect which fields are empty
- for (SchemaPath sp : columns) {
- PathSegment fieldPath = sp.getRootSegment();
+ for (SchemaPath schemaPath : columns) {
+ PathSegment fieldPath = schemaPath.getRootSegment();
BaseWriter.MapWriter fieldWriter = writer.rootAsMap();
+ TupleMetadata columnMetadata = schema;
while (fieldPath.getChild() != null && !fieldPath.getChild().isArray()) {
- fieldWriter = fieldWriter.map(fieldPath.getNameSegment().getPath());
+ String name = fieldPath.getNameSegment().getPath();
+ if (columnMetadata != null) {
+ ColumnMetadata metadata = columnMetadata.metadata(name);
+ columnMetadata = metadata != null ? metadata.mapSchema() : null;
+ }
+ fieldWriter = fieldWriter.map(name);
fieldPath = fieldPath.getChild();
}
writerList.add(fieldWriter);
fieldPathList.add(fieldPath);
+ // for the case when field is absent in the schema, use INT type
+ TypeProtos.MajorType majorType =
Types.optional(TypeProtos.MinorType.INT);
Review comment:
Maybe we add support for all text mode for MaprDB option in the scope of
this Jira as well?
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> Use Hive schema for MaprDB native reader when field was empty
> -------------------------------------------------------------
>
> Key: DRILL-7313
> URL: https://issues.apache.org/jira/browse/DRILL-7313
> Project: Apache Drill
> Issue Type: Task
> Affects Versions: 1.16.0
> Reporter: Volodymyr Vysotskyi
> Assignee: Volodymyr Vysotskyi
> Priority: Major
> Fix For: 1.17.0
>
>
> Currently, when an external Hive MaprDB table is queried using hive plugin
> with enabled {{store.hive.maprdb_json.optimize_scan_with_native_reader}},
> some queries may fail due to soft schema change, though Hive knows actual
> data types.
> For example, when we have a table with several fields, and one of them has
> only several non-null values, queries with grouping by such field will fail
> due to schema change.
> The goal of this Jira is to allow using types from Hive when a non-existing
> field is created, so it will allow avoiding such issues.
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