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> 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 ==========================================================
