Hi, I have reworked/refactored our Avro based logging system trying to make the whole Drill + Avro->Parquet experience a bit more agreeable.
Long story short I'm getting this error when selecting form multiple Avro files even though these files share the EXCACT same schema: Error: UNSUPPORTED_OPERATION ERROR: Hash aggregate does not support schema changes Fragment 0:0 [Error Id: 00d49aa2-5564-497e-a330-e852d5889beb on swift:31010] (state=,code=0) We are using union types but only to allow for null values as seems to be supported by drill as per this comment in the Drill code: // currently supporting only nullable union (optional fields) like ["null", "some-type"]. This happens for a very simple group_by + count(*) query that only uses two fields in Avro and neither one of them uses a Union construct so and both of them contain string values in every case. I know it's not popular to voice concerns here about Drill related matters but at this point I would like to advise everyone to stay clear of using Avro with Drill except for the most basic of cases. Regards, -Stefán
