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https://issues.apache.org/jira/browse/HIVE-13974?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15371746#comment-15371746
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Owen O'Malley commented on HIVE-13974:
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{quote}
No, the semantics of sameCategoryAndAttributes is different than equals.
{quote}
*Sigh* Ok, I forgot that I had only fixed that on the ORC side of the world as
part of ORC-53. Hive will get that as soon as HIVE-14007 goes in (or is a
negative patch of 2MB "going out"?). In any case, do not add the new method.
ORC-53's impact on orc-core is pretty small outside of TypeDescription. Would
you like a back port of that patch?
{quote}
There are 3 kinds of schema not 2.
{quote}
Ugh. That seems unnecessary. The 'file' schema is pretty clear. The 'reader'
schema is the one that the user asked for. I don't think we need anything else.
{quote}
About ORC-54 -- it is not practical right now in terms of time.
{quote}
ORC-54 is closer to going in. It has unit tests and I believe handles this as a
sub-case. I'm trying to figure out what we gain out of the HIVE-13974 patch.
{quote}
Also, there really needs to be a parallel HIVE JIRA for it and we must make
sure name mapping is fully supported for
Uh no. The Hive ORC code is about to disappear with HIVE-14007. Continuing to
maintain two versions of ORC with a forked code base is a bad thing.
{quote}
Given how *difficult* Schema Evolution has been I simply don't believe it will
*just work* with ORC only unit tests.
{quote}
That is not an excuse. Unit tests are MUCH more likely to be correct because
the errors aren't hidden under layers of the execution engine.
> ORC Schema Evolution doesn't support add columns to non-last STRUCT columns
> ---------------------------------------------------------------------------
>
> Key: HIVE-13974
> URL: https://issues.apache.org/jira/browse/HIVE-13974
> Project: Hive
> Issue Type: Bug
> Components: Hive, ORC, Transactions
> Affects Versions: 1.3.0, 2.1.0, 2.2.0
> Reporter: Matt McCline
> Assignee: Matt McCline
> Priority: Blocker
> Attachments: HIVE-13974.01.patch, HIVE-13974.02.patch,
> HIVE-13974.03.patch, HIVE-13974.04.patch, HIVE-13974.05.WIP.patch,
> HIVE-13974.06.patch, HIVE-13974.07.patch, HIVE-13974.08.patch,
> HIVE-13974.09.patch, HIVE-13974.091.patch
>
>
> Currently, the included columns are based on the fileSchema and not the
> readerSchema which doesn't work for adding columns to non-last STRUCT data
> type columns.
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