Hi, it's because the Outer Joins will generate retractions, consider the behavior of Left Outer Join
1. left record arrives, no matched right record, so +(left, null) will be generated. 2 right record arrives, the previous result should be retracted, so -(left, null) and +(left, right) will be generated Andres Angel <ingenieroandresan...@gmail.com> 于2019年7月25日周四 上午8:15写道： > Hello guys I have registered some table environments and now I'm trying to > perform a query on these using LEFT JOIN like the example below: > > Table fullenrichment = tenv.sqlQuery( > "SELECT pp.a,pp.b,pp.c,pp.d,pp.a " + > " FROM t1 pp LEFT JOIN t2 ent" + > " ON pp.b = ent.b" + > " LEFT JOIN t3 act " + > " ON pp.a = act.a " > ); > > Once the query is complete I need to read this into a Row DS > > DS<Row> results = tenv.toAppendStream(fullenrichment,Row.class); > > I'm getting the following error, however, if I execute the same code but > instead that LEFT JOIN I switch by INNER JOIN the error is vanished and the > code works , why this behavior? > > 1930 [main] INFO > org.apache.flink.streaming.connectors.kinesis.FlinkKinesisConsumer - > Flink Kinesis Consumer is going to read the following streams: > tr-stream-ingestion, > 3698 [main] INFO org.apache.flink.api.java.typeutils.TypeExtractor - > class org.apache.flink.types.Row does not contain a getter for field fields > 3698 [main] INFO org.apache.flink.api.java.typeutils.TypeExtractor - > class org.apache.flink.types.Row does not contain a setter for field fields > 3698 [main] INFO org.apache.flink.api.java.typeutils.TypeExtractor - > Class class org.apache.flink.types.Row cannot be used as a POJO type > because not all fields are valid POJO fields, and must be processed as > GenericType. Please read the Flink documentation on "Data Types & > Serialization" for details of the effect on performance. > 3730 [main] INFO org.apache.flink.api.java.typeutils.TypeExtractor - > class org.apache.flink.types.Row does not contain a getter for field fields > 3730 [main] INFO org.apache.flink.api.java.typeutils.TypeExtractor - > class org.apache.flink.types.Row does not contain a setter for field fields > 3730 [main] INFO org.apache.flink.api.java.typeutils.TypeExtractor - > Class class org.apache.flink.types.Row cannot be used as a POJO type > because not all fields are valid POJO fields, and must be processed as > GenericType. Please read the Flink documentation on "Data Types & > Serialization" for details of the effect on performance. > 3753 [main] INFO org.apache.flink.api.java.typeutils.TypeExtractor - > class org.apache.flink.types.Row does not contain a getter for field fields > 3753 [main] INFO org.apache.flink.api.java.typeutils.TypeExtractor - > class org.apache.flink.types.Row does not contain a setter for field fields > 3753 [main] INFO org.apache.flink.api.java.typeutils.TypeExtractor - > Class class org.apache.flink.types.Row cannot be used as a POJO type > because not all fields are valid POJO fields, and must be processed as > GenericType. Please read the Flink documentation on "Data Types & > Serialization" for details of the effect on performance. > Exception in thread "main" org.apache.flink.table.api.TableException: > Table is not an append-only table. Use the toRetractStream() in order to > handle add and retract messages. > at > org.apache.flink.table.api.StreamTableEnvironment.translate(StreamTableEnvironment.scala:920) > at > org.apache.flink.table.api.StreamTableEnvironment.translate(StreamTableEnvironment.scala:896) > at > org.apache.flink.table.api.java.StreamTableEnvironment.toAppendStream(StreamTableEnvironment.scala:308) > at > org.apache.flink.table.api.java.StreamTableEnvironment.toAppendStream(StreamTableEnvironment.scala:262) > at consumer.trconsumer.main(trconsumer.java:180) >
