[AVRO-2148] Avro: Schema compatibility/evolution - attribute size change

• Type: Improvement
• Status: Open
• Priority: Critical
• Resolution: Unresolved
• Affects Version/s: 1.8.2
• Component/s: spec
• Labels: patch
• Tags: avro
• Assignee: Unassigned
• Reporter: Ashok
• Created: 21/Feb/18 23:08
• Updated: 30/Dec/18 05:24

Description

Let's assume the schema changed from V1 to V2.  Currently, we can't create a merge of the two schema that makes it a compatible for both.  Depending on what size we keep for the specific attribute in the reader schema (the merged), you can read avro files of schema V1 or V2, but not both.  If we keep the higher attribute size value (64) as part of the merged schema, it should allow the read of avro files with lower attribute size value (16)

 

• V1 schema:

{ "name": "sid", "type": [ "null",

{ "type": "fixed", "name": "SID", "namespace": "com.int.datatype", "doc": "", "size": *64* }

], "doc": "", "default": null, "businessLogic": "" }

 

• V2 schema:

{ "name": "sid", "type": [ "null",

{ "type": "fixed", "name": "SID", "namespace": "com.int.datatype", "doc": "", "size": *16* }

], "doc": "", "default": null, "businessLogic": "" }