[ https://issues.apache.org/jira/browse/AVRO-1704?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15189594#comment-15189594 ]
Doug Cutting commented on AVRO-1704: ------------------------------------ bq. remove the things that do not impact the binary form of the record This is already done as part of fingerprint calculation. https://avro.apache.org/docs/current/spec.html#Parsing+Canonical+Form+for+Schemas Also, if we opt for a prefix, we might use something like 'A'+'v'+'r'+0, where the last character also indicates the format version, including schema hash function. That's similar to what's used to label the file format, and has a side benefit of clearly demonstrating that this is binary, non-textual data. > Standardized format for encoding messages with Avro > --------------------------------------------------- > > Key: AVRO-1704 > URL: https://issues.apache.org/jira/browse/AVRO-1704 > Project: Avro > Issue Type: Improvement > Reporter: Daniel Schierbeck > > I'm currently using the Datafile format for encoding messages that are > written to Kafka and Cassandra. This seems rather wasteful: > 1. I only encode a single record at a time, so there's no need for sync > markers and other metadata related to multi-record files. > 2. The entire schema is inlined every time. > However, the Datafile format is the only one that has been standardized, > meaning that I can read and write data with minimal effort across the various > languages in use in my organization. If there was a standardized format for > encoding single values that was optimized for out-of-band schema transfer, I > would much rather use that. > I think the necessary pieces of the format would be: > 1. A format version number. > 2. A schema fingerprint type identifier, i.e. Rabin, MD5, SHA256, etc. > 3. The actual schema fingerprint (according to the type.) > 4. Optional metadata map. > 5. The encoded datum. > The language libraries would implement a MessageWriter that would encode > datums in this format, as well as a MessageReader that, given a SchemaStore, > would be able to decode datums. The reader would decode the fingerprint and > ask its SchemaStore to return the corresponding writer's schema. > The idea is that SchemaStore would be an abstract interface that allowed > library users to inject custom backends. A simple, file system based one > could be provided out of the box. -- This message was sent by Atlassian JIRA (v6.3.4#6332)