Use orcfiledump to see the stats for each column etc
Example hive --orcfiledump --rowindex 1,2 /user/hive/warehouse/oraclehadoop.db/orctest/000000_0 Dr Mich Talebzadeh LinkedIn https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABUrV8Pw Sybase ASE 15 Gold Medal Award 2008 A Winning Strategy: Running the most Critical Financial Data on ASE 15 http://login.sybase.com/files/Product_Overviews/ASE-Winning-Strategy-091908.pdf Author of the books "A Practitioner’s Guide to Upgrading to Sybase ASE 15", ISBN 978-0-9563693-0-7. co-author "Sybase Transact SQL Guidelines Best Practices", ISBN 978-0-9759693-0-4 Publications due shortly: Complex Event Processing in Heterogeneous Environments, ISBN: 978-0-9563693-3-8 Oracle and Sybase, Concepts and Contrasts, ISBN: 978-0-9563693-1-4, volume one out shortly http://talebzadehmich.wordpress.com <http://talebzadehmich.wordpress.com/> NOTE: The information in this email is proprietary and confidential. This message is for the designated recipient only, if you are not the intended recipient, you should destroy it immediately. Any information in this message shall not be understood as given or endorsed by Peridale Technology Ltd, its subsidiaries or their employees, unless expressly so stated. It is the responsibility of the recipient to ensure that this email is virus free, therefore neither Peridale Technology Ltd, its subsidiaries nor their employees accept any responsibility. From: Philip Lee [mailto:philjj...@gmail.com] Sent: 01 February 2016 15:27 To: user@hive.apache.org Subject: Re: ORC format Also, when making ORC from CSV, for indexing every key on each coulmn is made, or a primary on a table is made ? If keys are made on each column in a table, accessing any column in some functions like filtering should be faster. On Mon, Feb 1, 2016 at 4:21 PM, Philip Lee <philjj...@gmail.com <mailto:philjj...@gmail.com> > wrote: Hello, I experiment the performance of some systems between ORC and CSV file. I read about ORC documentation on Hive website, but still curious of some things. I know ORC format is faster on filtering or reading because it has indexing. Has it advantage of joining two tables of ORC dataset as well? Could you explain about it in detail? When experimenting, it seems like it has some advantages of joining in some aspect, but not quite sure what characteristic of ORC make this happening rather than CSV. Best, Phil -- ========================================================== Hae Joon Lee Now, in Germany, M.S. Candidate, Interested in Distributed System, Iterative Processing Dept. of Computer Science, Informatik in German, TUB Technical University of Berlin In Korea, M.S. Candidate, Computer Architecture Laboratory Dept. of Computer Science, KAIST Rm# 4414 CS Dept. KAIST 373-1 Guseong-dong, Yuseong-gu, Daejon, South Korea (305-701) Mobile) 49) 015-251-448-278 in Germany, no cellular in Korea ==========================================================
