Writing Data

Caused by: org.apache.parquet.io.InvalidRecordException: Parquet/Avro schema mismatch: Avro field 'col1' not found

It is recommended that schema should evolve in backwards compatible way while using Hudi. Please refer here for more information on avro schema resolution - https://avro.apache.org/docs/1.8.2/spec.html. This error generally occurs when the schema has evolved in backwards incompatible way by deleting some column 'col1' and we are trying to update some record in parquet file which has alredy been written with previous schema (which had 'col1'). In such cases, parquet tries to find all the present fields in the incoming record and when it finds 'col1' is not present, the mentioned exception is thrown.

The fix for this is to try and create uber schema using all the schema versions evolved so far for the concerned event and use this uber schema as the target schema. One of the good approaches can be fetching schema from hive metastore and merging it with the current schema.

Ingestion

Caused by: java.io.EOFException: Received -1 when reading from channel, socket has likely been closed.
at kafka.utils.Utils$.read(Utils.scala:381)
at kafka.network.BoundedByteBufferReceive.readFrom(BoundedByteBufferReceive.scala:54)

This might happen if you are ingesting from Kafka source, your cluster is ssl enabled by default and you are using some version of Hudi older than 0.5.1. Previous versions of Hudi were using spark-streaming-kafka-0-8 library. With the release of 0.5.1 version of Hudi, spark was upgraded to 2.4.4 and spark-streaming-kafka library was upgraded to spark-streaming-kafka-0-10. SSL support was introduced from spark-streaming-kafka-0-10. Please see here for reference. 

The workaround can be either use Kafka cluster which is not ssl enabled, else upgrade Hudi version to at least 0.5.1 or spark-streaming-kafka library to spark-streaming-kafka-0-10.

Hive Sync

Caused by: java.sql.SQLException: Error while processing statement: FAILED: Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask. Unable to alter table. The following columns have types incompatible with the existing columns in their respective positions :
__col1,__col2

This will usually happen when you are trying to add a new column to existing hive table using our HiveSyncTool.java class. Databases usually will not allow to modify a column datatype from a higher order to lower order or cases where the datatypes may clash with the data that is already stored/will be stored in the table. To fix the same, try setting the following property - 

set hive.metastore.disallow.incompatible.col.type.changes=false;