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From "Owen O'Malley" <omal...@apache.org>
Subject Re: [jira] [Created] (ORC-120) Create a backwards compatibility mode of ignoring names for evolution
Date Tue, 13 Dec 2016 00:14:14 GMT
No, unfortunately, but it needs to be. The basic rules from
SchemaEvolution.java look like:

structs (including the top row):
   if field names are available (post HIVE-4243), use name matching
   otherwise use positional matching

lists, maps, unions:
  children must match

Many primitives can convert to each other, but this list needs to be
cleaned up:
  boolean, byte, short, int, long, float, double, decimal -> boolean, byte,
short, int, long, float, double, decimal, string, char, varchar, timestamp
  string, char, varchar -> all
  timestamp -> boolean, byte, short, int, long, float, double, decimal,
string, char, varchar, date
  date -> string, char, varchar, timestamp
  binary -> string, char, varchar, date

.. Owen

On Mon, Dec 12, 2016 at 2:55 PM, Dain Sundstrom <dain@iq80.com> wrote:

> Is "ORC's schema evolution uses the column names when they are available”
> documented somewhere?
>
> -dain
>
> > On Dec 12, 2016, at 2:24 PM, Owen O'Malley (JIRA) <jira@apache.org>
> wrote:
> >
> > Owen O'Malley created ORC-120:
> > ---------------------------------
> >
> >             Summary: Create a backwards compatibility mode of ignoring
> names for evolution
> >                 Key: ORC-120
> >                 URL: https://issues.apache.org/jira/browse/ORC-120
> >             Project: Orc
> >          Issue Type: Task
> >            Reporter: Owen O'Malley
> >
> >
> > ORC's schema evolution uses the column names when they are available.
> Hive 2.1 uses a positional schema, so ORC should support a backward
> compatibility mode for Hive users during the transition.
> >
> >
> >
> > --
> > This message was sent by Atlassian JIRA
> > (v6.3.4#6332)
>
>

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