1) You can find the public headers in c++/include/orc. All the classes and 
methods have good documentation in the code. You can also take a look at the 
sample c++ codes under tools/src, especially 
FileContents.cc<http://FileContents.cc> and FileScan.cc<http://FileScan.cc>. 
Both demonstrate the usage of c++ reader.

2) What you are mentioning is a feature we call “Predicate Pushdown”. 
Unfortunately it is not supported by c++ reader currently. The java reader does 
support it through SearchArgument class. I assume the implementation would be 
similar for c++ when we add this support in the future.


On Nov 1, 2018, at 1:28 PM, Korry Douglas 
<[email protected]<mailto:[email protected]>> wrote:

Hi all - I’m an absolute ORC newbie so please forgive the novice questions.

I’m trying to use the C++ API to implement a reader.  I have two questions (to 
start with):

1) I’ve been reading the docs at https://orc.apache.org/docs/core-cpp.html - is 
there more complete documentation that describes all of the public classes that 
I can use?

2) My understanding is that an ORC file contains min/max indexes that can help 
me reduce the amount of data I have to read to satisfy a given query.  Is there 
a class that I can use to specify the range of values that I want to read?  Or 
do I have to read the statistics myself (for each stripe?) and manually inspect 
the min/max values.

Thanks in advance.


            — Korry

Reply via email to