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Gaurav Jain commented on PIG-1104: ---------------------------------- +1 > [zebra] Provide streaming support in Zebra. > ------------------------------------------- > > Key: PIG-1104 > URL: https://issues.apache.org/jira/browse/PIG-1104 > Project: Pig > Issue Type: New Feature > Affects Versions: 0.4.0 > Reporter: Chao Wang > Assignee: Chao Wang > Fix For: 0.6.0, 0.7.0 > > Attachments: PIG1104.patch > > > Hadoop streaming is very popular among Hadoop users. The main attraction is > the simplicity of use. A user can write the application logic in any language > and process large amounts of data using Hadoop framework. As more people > start to use Zebra to store their data, we expect users would like to run > Hadoop streaming scripts to easily process Zebra tables. > The following lists a simple example of using Hadoop streaming to access > Zebra data. It loads data from foo table using Zebra's TableInputFormat and > then writes the data into output using default TextOutputFormat. > $ hadoop jar hadoop-streaming.jar -D mapred.reduce.tasks=0 -input foo -output > output -mapper 'cat' -inputformat > org.apache.hadoop.zebra.mapred.TableInputFormat > More detailed, Zebra uses Pig DefaultTuple implementation of Tuple for its > records. Currently, when Zebra's TableInputFormat is used for input, the user > script sees each line containing " key_if_any\tTuple.toString() ". We plan to > generate CSV format representation of our Pig tuples. To this end, we plan to > do the following: > 1) Derive a sub class ZupleTuple from pig's DefaultTuple class and override > its toString() method to present the data into CSV format. > 2) On Zebra side, the tuple factory should be changed to create ZebraTuple > objects, instead of DefaultTuple objects. > Note that we can only support streaming on the input side - ability to use > streaming to read data from Zebra tables. For the output side, the streaming > support is not feasible, since the streaming mapper or reducer only emits > "Text\tText", the output collector has no way of knowing how to convert this > to (BytesWritable,Tuple). -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.