I got it. Makes total sense! Thank you for your explanation.
On Fri, 2013-05-31 at 20:04 +0000, Sanjay Subramanian wrote: > Hi > Hive reads and writes to HDFSŠand by definition HDFS is write once and > immutable after that. > So like an RDBMS there is no concept of an update rows. > However if u want to delete some records based on a criteria, yesterday > there was a smart post about it, basically selecting the inverse and doing > an INSERT OVERWRITE on the table > > INSERT OVERWRITE TABLE will write to the Hive managed HDFS location of > that table and "replace" all that is there with your latest > > INSERT OVERWRITE DIRECTORY will write to your HDFS location of choice and > "replace" all that is there with your latest. You can use this directory > as LOCATION to which your PARTITION may point later > > > Note that INSERT OVERWRITE TABLE will follow the field separator of the > destination table that u specified while creating the table > > However INSERT OVERWRITE DIRECTORY will have Hive's default "CtrlA" as the > field separator ( I use 0.10.x)Šperhaps this is changed in 0.11 u need to > verify > > In summary , u have to look at updates and deletes very differently from > RDBMS > > Good luck > > sanjay > > > > > > On 5/31/13 12:27 PM, "Renata Ghisloti Duarte de Souza" > <rgdua...@linux.vnet.ibm.com> wrote: > > >Hello, > > > >I was wondering about the "update" statement on Hive. Is it something > >Hive needs? Or can "insert overwrite" be always used instead? > > > >Thank you in advance for the clarification, > > > >Renata. > > > > > > > > > CONFIDENTIALITY NOTICE > ====================== > This email message and any attachments are for the exclusive use of the > intended recipient(s) and may contain confidential and privileged > information. Any unauthorized review, use, disclosure or distribution is > prohibited. If you are not the intended recipient, please contact the sender > by reply email and destroy all copies of the original message along with any > attachments, from your computer system. If you are the intended recipient, > please be advised that the content of this message is subject to access, > review and disclosure by the sender's Email System Administrator. >
