[GitHub] [orc] wgtmac commented on a change in pull request #476: ORC-40: [C++] Implement Predicate Pushdown for C++ Reader

[GitBox <gi...@apache.org>]

wgtmac commented on a change in pull request #476:
URL: https://github.com/apache/orc/pull/476#discussion_r578095884



##########
File path: c++/src/Reader.hh
##########
@@ -19,13 +19,14 @@
 #ifndef ORC_READER_IMPL_HH
 #define ORC_READER_IMPL_HH
 
+#include "orc/Exceptions.hh"
 #include "orc/Int128.hh"
 #include "orc/OrcFile.hh"
 #include "orc/Reader.hh"
 
 #include "ColumnReader.hh"
-#include "orc/Exceptions.hh"

Review comment:
       Unfortunately I don't think we had a clear C++ coding style. Maybe we can use cpplint tool to enfoce it.

##########
File path: c++/src/ColumnReader.cc
##########
@@ -1553,6 +1558,8 @@ namespace orc {
     ColumnReader::seekToRowGroup(positions);
     valueStream->seek(positions.at(columnId));
     scaleDecoder->seek(positions.at(columnId));
+    buffer = nullptr;
+    bufferEnd = nullptr;

Review comment:
       This is actually a bug if we call seek() several times. In the past this is not a issue because we only call seek() once and the stream state is correct. But if PPD is enabled, we may call seek() at any point, then the stream state is very important.




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