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https://issues.apache.org/jira/browse/HIVE-4322?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13630605#comment-13630605
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Phabricator commented on HIVE-4322:
-----------------------------------
gangtimliu has accepted the revision "HIVE-4322 [jira] SkewedInfo in Metastore
Thrift API cannot be deserialized in Python".
thanks
REVISION DETAIL
https://reviews.facebook.net/D10203
BRANCH
svn
ARCANIST PROJECT
hive
To: gangtimliu, sxyuan
Cc: kevinwilfong, JIRA
> SkewedInfo in Metastore Thrift API cannot be deserialized in Python
> -------------------------------------------------------------------
>
> Key: HIVE-4322
> URL: https://issues.apache.org/jira/browse/HIVE-4322
> Project: Hive
> Issue Type: Bug
> Components: Metastore, Thrift API
> Affects Versions: 0.11.0
> Reporter: Samuel Yuan
> Assignee: Samuel Yuan
> Priority: Minor
> Attachments: HIVE-4322.HIVE-4322.HIVE-4322.HIVE-4322.D10203.1.patch
>
>
> The Thrift-generated Python code that deserializes Thrift objects fails
> whenever a complex type is used as a map key, because by default mutable
> Python objects such as lists do not have a hash function. See
> https://issues.apache.org/jira/browse/THRIFT-162 for related discussion.
> The SkewedInfo struct contains a map which uses a list as a key, breaking the
> Python Thrift interface. It is not possible to specify the mapping from
> Thrift types to Python types, or otherwise we could map Thrift lists to
> Python tuples. Instead, the proposed workaround wraps the list inside a new
> struct. This alone does not accomplish anything, but allows Python clients to
> define a hash function for the struct class, e.g.:
> def f(object):
> return hash(tuple(object.skewedValueList))
> SkewedValueList.__hash__ = f
> In practice a more efficient hash might be defined that does not involve
> copying the list. The advantage of wrapping the list inside a struct is that
> the client does not have to define the hash on the list itself, which would
> change the behaviour of lists everywhere else in the code.
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