xushiyan commented on a change in pull request #1584:
URL: https://github.com/apache/incubator-hudi/pull/1584#discussion_r419919337
##########
File path:
hudi-utilities/src/main/java/org/apache/hudi/utilities/deltastreamer/SourceFormatAdapter.java
##########
@@ -64,19 +64,22 @@ public SourceFormatAdapter(Source source) {
}
case ROW: {
InputBatch<Dataset<Row>> r = ((RowSource)
source).fetchNext(lastCkptStr, sourceLimit);
- return new InputBatch<>(Option.ofNullable(r.getBatch().map(
- rdd -> (
- (r.getSchemaProvider() instanceof FilebasedSchemaProvider)
- // If the source schema is specified through Avro schema,
- // pass in the schema for the Row-to-Avro conversion
- // to avoid nullability mismatch between Avro schema and
Row schema
- ? AvroConversionUtils.createRdd(
- rdd, r.getSchemaProvider().getSourceSchema(),
- HOODIE_RECORD_STRUCT_NAME,
HOODIE_RECORD_NAMESPACE).toJavaRDD()
- : AvroConversionUtils.createRdd(
- rdd, HOODIE_RECORD_STRUCT_NAME,
HOODIE_RECORD_NAMESPACE).toJavaRDD()
- ))
- .orElse(null)), r.getCheckpointForNextBatch(),
r.getSchemaProvider());
+ if (r.getBatch().isPresent()) {
Review comment:
> If I understand correctly, not specifying schema provider should be
feasible in case of row based sources when you try to fetch the data in row
format (i.e when using transformers).
hi @pratyakshsharma I don't quite get this point. I'm referring
to`fetchNewDataInAvroFormat()` being called when transformer is not set
https://github.com/apache/incubator-hudi/blob/14d4fea8339913c0df8ea829036a45a187c55208/hudi-utilities/src/main/java/org/apache/hudi/utilities/deltastreamer/DeltaSync.java#L305-L306
in case of ROW type source and no new data, `r.getSchemaProvider()` will
throw an exception.
An example use case: reading a parquet source (ROW format) without setting
either transformer or schemaprovider class, it works when new data keeps
coming. But an exception will be thrown when no new data detected, calling
`r.getSchemaProvider()` in this switch case will ask user to set schemaprovider.
If in this example we still require users to set schema provider (like the
built-in RowBasedSchemaProvider), then it conflicts with ROW source getting
implicit schema. It seems like a usability issue.
Could you confirm this understanding is accurate please?
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