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From "Ryan Blue (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (AVRO-1402) Support for DECIMAL type
Date Tue, 08 Apr 2014 16:34:21 GMT

    [ https://issues.apache.org/jira/browse/AVRO-1402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13963146#comment-13963146

Ryan Blue commented on AVRO-1402:

bq. There have been objections to the approach implemented here on the basis that there’s
no a clear use case for storing decimals with different scales in the same field.

I think there is a use case that avro needs to care about: `BigDecimal` is used to avoid floating
point error, but not just for money where scale is almost always 2. If I'm storing precise
measurements, I could end up with different incoming scales from different equipment used
to take the measurement. This works just fine up until the `BigDecimal` is stored in avro,
at which point avro would throw an exception and force the caller to mutate the data, if avro
forces data points to have the same scale.

There are real-world cases where this happens. GPS data comes to mind, where newer receivers
have better location resolution and it's important to keep the most precise measurement taken.

> Support for DECIMAL type
> ------------------------
>                 Key: AVRO-1402
>                 URL: https://issues.apache.org/jira/browse/AVRO-1402
>             Project: Avro
>          Issue Type: New Feature
>    Affects Versions: 1.7.5
>            Reporter: Mariano Dominguez
>            Assignee: Tom White
>            Priority: Minor
>              Labels: Hive
>             Fix For: 1.7.7
>         Attachments: AVRO-1402.patch, AVRO-1402.patch, AVRO-1402.patch, AVRO-1402.patch,
> Currently, Avro does not seem to support a DECIMAL type or equivalent.
> http://avro.apache.org/docs/1.7.5/spec.html#schema_primitive
> Adding DECIMAL support would be particularly interesting when converting types from Avro
to Hive, since DECIMAL is already a supported data type in Hive (0.11.0).

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