-Re: Hive Architecture - Execution on nodes
Alan Gates 2013-07-18, 21:45
On Jul 18, 2013, at 1:40 PM, Tzur Turkenitz wrote:
> Just finished reading the Hive-Architecture pdf, and failed to find the answers I was hoping for. So here I am, hoping this community will shed some light.
> I think I know what the answers will be, I need that bolted down and secured.
> We are concerned on how data is transferred between data-nodes and hive, especially when it comes to clusters were there’s no SSL between nodes.
> And this is the user-case:
> 1. Table employee is a Hive table, with SerDe
> 2. MapReduce job accesses the table Employees which holds Encrypted data
> 3. SerDe decrypts the data
> 4. Post-SerDe output is returned to the MapReduce job and saved to a new Hive table using a new Encryption implementation
> The flow, as I think it currently is should be:
> MapReduce Job -- > Read table metadata -- > SerDe creates map-reduce job -- > distributes across nodes
> Which means that data is decrypted on the local nodes and then sent in clear-text back to the original map-reduce job to be saved in a new table.
> Is that correct? L
No. Data deserialization (which is what a serde does, not decryption) is done as part of reading in the map reduce job. Mainly only query parsing, validation, and planning is done on the client node.