[
https://issues.apache.org/jira/browse/AVRO-2164?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16411673#comment-16411673
]
Hans-Peter Werner commented on AVRO-2164:
-----------------------------------------
"Lossy" in that you dont have the scale stored with the data AND you dont get
it provided by AVRO out of the box. It didnt want stress the term too much :).
The idea of decimal being a first class member came to my mind also some days
ago, when I wrote a workaround for nullable decimals (as a POC). But I think it
just hides the problem.
> Make Decimal a first class type.
> --------------------------------
>
> Key: AVRO-2164
> URL: https://issues.apache.org/jira/browse/AVRO-2164
> Project: Avro
> Issue Type: Improvement
> Components: logical types
> Affects Versions: 1.8.2
> Reporter: Andy Coates
> Priority: Major
>
> I'd be interested to hear the communities thoughts on making decimal a first
> class type.
> The current logical type encodes a decimal into a _bytes_ or _fixed_. This
> encoding does not include any information about the scale, i.e. this encoding
> is lossy.
> There are open issues around the compatibility / evolvability of schemas
> containing decimal logical types, (e.g. AVRO-2078 & AVRO-1721), that mean
> reading data that was previously written with a different scale will result
> in data corruption.
> If these issues were fixed, with suitable compatibility checks put in place,
> this would then make it impossible to evolve an Avro schema where the scale
> needs to be changed. This inability to evolve the scale is very restrictive,
> and can result in high overhead for organizations that _need_ to change the
> scale, i.e. they may potentially need to copy their entire data set,
> deserializing with the old scale and re-serializing with the new.
> If _decimal_ were promoted to a first class type, this would allow the scale
> to be captured in the serialized form, allow for schema evolution support.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
