It takes effect when i use "alter table tablename concatenate" after a insert sql thanks
2014-08-29 0:44 GMT+08:00 Prasanth Jayachandran < pjayachand...@hortonworks.com>: > Hi > > If its an rcfile you can use "alter table tablename concatenate" to merge > them into 1 file. For text files, you can may have to reload these 2 files > into another table with "Order By". This will force one reducer to generate > total ordering and thereby generating 1 output file. But remember if the > data size huge order by will take very long time. > > Thanks > Prasanth > > On Aug 28, 2014, at 7:45 AM, 王洋 <wangyang....@gmail.com> wrote: > > Hello, > I have two table ,one is stored as textfile for loading data from > local data, the other is stored as rcfile for compressing data。 > when I execute the following sql two times > > * insert into table tablename1 select * from tablename2* > > I find that there are two files in the warehouse > > *hadoop fs -ls /user/hive/warehouse/**tablename2**/* > * Found 2 items* > * -rwxrwxrwt 3 root supergroup 423 2014-08-28 21:09 > /user/hive/warehouse/**tablename2**/000000_0* > * -rwxrwxrwt 3 root supergroup 423 2014-08-28 21:11 > /user/hive/warehouse/**tablename2**/000000_0_copy_1* > > I need to merge the two files to reduce the small file, is there have > some way to merge the files? > thank you ! > > > CONFIDENTIALITY NOTICE > NOTICE: This message is intended for the use of the individual or entity > to which it is addressed and may contain information that is confidential, > privileged and exempt from disclosure under applicable law. If the reader > of this message is not the intended recipient, you are hereby notified that > any printing, copying, dissemination, distribution, disclosure or > forwarding of this communication is strictly prohibited. If you have > received this communication in error, please contact the sender immediately > and delete it from your system. Thank You.
