[
https://issues.apache.org/jira/browse/PIG-993?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12761766#action_12761766
]
Raghu Angadi commented on PIG-993:
----------------------------------
API is pretty simple : {code}
class org.apache.hadoop.zebra.BasicTable {
/** see the patch for JavaDoc and attached example for usage */
public static void dropColumnGroup(Path path,
Configuration conf, String cgName)
throws IOException { ... }
}
{code}
* Table schema is not modified.
* this API takes a name for a column group. PIG-986 adds explicit names for
CGs.
* Once a CGs is deleted, NULL is returned for the fields that were stored in
the CG.
** This is the main difference between just manually deleting a directory
on filesystem and 'properly' deleting a CG.
** Many changes made in other parts of zebra are related to handling the
missing CGs.
> [zebra] Abitlity to drop a column group in a table
> --------------------------------------------------
>
> Key: PIG-993
> URL: https://issues.apache.org/jira/browse/PIG-993
> Project: Pig
> Issue Type: Bug
> Reporter: Raghu Angadi
> Assignee: Raghu Angadi
> Fix For: 0.5.0
>
>
> A Zebra table is stored as multiple sub tables each containing a set of
> columns called column group (CG). The user specifies how these columns are
> grouped while creating a table through the _storage hint_.
> For some of the large tables, it might be necessary for users to remove a set
> of columns and retain the rest. This jira provides a way for users to delete
> an entire column group.
> The following comments will have more details on API and the semantics.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
