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https://issues.apache.org/jira/browse/KUDU-721?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15318450#comment-15318450
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Todd Lipcon commented on KUDU-721:
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As far as I know, no one is currently working on this one. I agree it's a must
for a lot of use cases, but as always in software, time is limited :) In terms
of development, I think this is probably tricky enough that a short design
document would be necessary. As a rough guide (and without having looked in
depth) I think the implementation would have to look something like:
- introduce the concept of 'type parameters'. DECIMAL needs both a 'precision'
and 'scale' parameter.
-- not entirely sure if the type parameters would be part of TypeInfo (in which
case TypeInfo becomes less of a singleton) or part of ColumnSchema. I think the
latter, but not certain.
- introduce APIs to specify these when creating a table, read them back out of
table schema info, etc.
- introduce client APIs to read and write DECIMAL values with precision (i.e
not by conversion to/from float), perhaps involving some limited form of
coercion between different scales and precisions.
- similar for supporting range predicates on DECIMAL - coercion may be important
It's certainly not a "starter" project- I'd estimate a couple weeks work for
someone already familiar with Kudu internals, maybe a couple months fulltime
for someone getting up to speed.
> Support for DECIMAL type
> ------------------------
>
> Key: KUDU-721
> URL: https://issues.apache.org/jira/browse/KUDU-721
> Project: Kudu
> Issue Type: New Feature
> Components: client, tablet
> Affects Versions: Private Beta
> Reporter: Todd Lipcon
> Priority: Critical
> Labels: kudu-roadmap
>
> [~mgrund] identified that without DECIMAL type, we're going to have issues
> with a lot of the tests tables that Impala uses. Also, since we're targeting
> some financial applications, it seems pretty crucial. This JIRA is to track
> the work necessary to support it. I'll write up some short design doc and
> post here.
> *Design doc*:
> https://docs.google.com/a/cloudera.com/document/d/1wIebU0HxviRLHFF1fSS-E30KPWOrTI0xVYAMPE6kliU/edit?usp=sharing
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