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https://issues.apache.org/jira/browse/ORC-968?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17407818#comment-17407818
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Dongjoon Hyun commented on ORC-968:
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Is there any update on this issue, [~stigahuang]?
> [C++] Column names used to build SearchArgument should be full path names
> -------------------------------------------------------------------------
>
> Key: ORC-968
> URL: https://issues.apache.org/jira/browse/ORC-968
> Project: ORC
> Issue Type: Sub-task
> Components: C++
> Affects Versions: 1.7.0
> Reporter: Quanlong Huang
> Priority: Blocker
>
> The C++ reader provides the same interfaces as those in hive-storage-api for
> building SearchArguments, e.g.
> {code:cpp}
> virtual SearchArgumentBuilder& lessThan(const std::string& column,
> PredicateDataType type,
> Literal literal) = 0;
> {code}
> C++:
> [https://github.com/apache/orc/blob/2143841e24abb2e0fef1a3396376682fc3bb6fea/c%2B%2B/include/orc/sargs/SearchArgument.hh#L90-L92]
> Java:
> [https://github.com/apache/hive/blob/620b2b197269041d7f508bd0e4564ed8e5edfcfd/storage-api/src/java/org/apache/hadoop/hive/ql/io/sarg/SearchArgument.java#L219-L220]
> However, the column strings in Java codes are treated as full path names
> instead of the leaf field names. E.g. for a nested column 'id' inside a
> struct type column 's', the name string is expected to be 's.id' instead of
> 'id'.
> More details about the string format:
> {quote}Find a subtype of this schema by name. If the name is a simple
> integer, it will be used as a column number. Otherwise, this routine will
> recursively search for the name. * Struct fields are selected by name.
> * List children are selected by "_elem".
> * Map children are selected by "_key" or "_value".
> * Union children are selected by number starting at 0.
> Names are separated by '.'.
> {quote}
> [https://javadoc.io/doc/org.apache.orc/orc-core/1.6.10/org/apache/orc/TypeDescription.html#findSubtype-java.lang.String-]
> The C++ library currently treats the name strings as struct field names and
> recursively searching it in SargsApplier::findColumn
>
> [https://github.com/apache/orc/blob/2143841e24abb2e0fef1a3396376682fc3bb6fea/c%2B%2B/src/sargs/SargsApplier.cc#L25-L39]
> To be consistent with Java codes and to avoid ambiguous selection (if there
> are identical sub-field names in different struct columns), we should adjust
> the C++ library to treat name strings as full path names. It should also deal
> with special names like "_elem", "_key", and "_value".
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