Andy Coates created AVRO-2164:
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Summary: 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
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.
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