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Joris Van den Bossche commented on ARROW-14805: ----------------------------------------------- Yes, I would indeed be good to implement the fast path for this. > [C++] Support Count function without projections in ORC to avoid loading all > columns > ------------------------------------------------------------------------------------ > > Key: ARROW-14805 > URL: https://issues.apache.org/jira/browse/ARROW-14805 > Project: Apache Arrow > Issue Type: Improvement > Components: C++ > Reporter: xiangxiang Shen > Priority: Major > Labels: ORC, c++, dataset > > For ORC support in dataset, when execute count query without projections, > just like "select count(*) from table", it will load all columns. Because orc > lib code is that > [https://github.com/apache/orc/blob/22828f79a526069d9629719c9476b7addad91ae6/c%2B%2B/src/Reader.cc#L120-L144.] > > Arrow side can improve it like parquet in dataset. -- This message was sent by Atlassian Jira (v8.20.1#820001)