Donutellko opened a new issue, #16782: URL: https://github.com/apache/druid/issues/16782
### Description Hello, we are trying to load data from a DeltaTable, and facing an issue with StructType (manually formatted error message): ``` Failed to sample data: Unsupported data type[ struct( StructField(name=FieldOne,type=string,nullable=true,metadata={}), StructField(name=FieldTwo,type=string,nullable=true,metadata={}) ) ] for fieldName[MetaData]. at org.apache.druid.error.DruidException$DruidExceptionBuilder.build(DruidException.java:460) at ... at org.apache.druid.error.InvalidInput.exception(InvalidInput.java:30) at org.apache.druid.delta.input.DeltaInputRow.getValue(DeltaInputRow.java:201) at org.apache.druid.delta.input.DeltaInputRow._getRaw(DeltaInputRow.java:163) at org.apache.druid.delta.input.DeltaInputRow.<init>(DeltaInputRow.java:74) at org.apache.druid.delta.input.DeltaInputSourceReader$DeltaInputSourceIterator.next(DeltaInputSourceReader.java:140) at ... ``` Expected behavior: * StructType's StructFields are loaded as a set of columns with a common prefix: `MetaData.FieldOne`, `MetaData.FieldTwo`, ...; * or (at least) StructType is loaded as a JSON string. * Additionally, I would like to discuss a possibility of loading delta **ArrayType** as a JSON string. ### Motivation - Storing StructType is a common approach for DeltaTables, and with Spark they are widely used to group some fields and accessing them like this: `.select(col("MetaData.FieldOne"))`. Supporting loading this data seems indispensable for a common use of druid-delta-extensions. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@druid.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@druid.apache.org For additional commands, e-mail: commits-h...@druid.apache.org