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Jing Huang commented on PIG-833: -------------------------------- Hi Yongqiang, Sorry for the late reply. I was out of town last week. Right, SF_F is not defined in the schema, query a none-existing column is allowed and it will return null. > Storage access layer > -------------------- > > Key: PIG-833 > URL: https://issues.apache.org/jira/browse/PIG-833 > Project: Pig > Issue Type: New Feature > Reporter: Jay Tang > Attachments: hadoop20.jar.bz2, PIG-833-zebra.patch, > PIG-833-zebra.patch.bz2, PIG-833-zebra.patch.bz2, > TEST-org.apache.hadoop.zebra.pig.TestCheckin1.txt, test.out, zebra-javadoc.tgz > > > A layer is needed to provide a high level data access abstraction and a > tabular view of data in Hadoop, and could free Pig users from implementing > their own data storage/retrieval code. This layer should also include a > columnar storage format in order to provide fast data projection, > CPU/space-efficient data serialization, and a schema language to manage > physical storage metadata. Eventually it could also support predicate > pushdown for further performance improvement. Initially, this layer could be > a contrib project in Pig and become a hadoop subproject later on. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.