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https://issues.apache.org/jira/browse/HIVE-1918?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12984563#action_12984563
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Krishna Kumar commented on HIVE-1918:
-------------------------------------
Why export/import needs this change: It is not the export part, but rather the
import part which needs this change. While creating a partition as part of an
import, we need to be able to create the partition along with its ancillary
data including partition parameters. But first part of the existing "create
partition" flow (AddPartitionDesc -> DDLTask.addPartition ->
Hive.createPartition) did not support partition params specification but the
second part (metastore.api.Partition -> IMetaStoreClient.add_partition ->
HiveMetaStore.HMSHandler.add_partition -> ObjectStore.addPartition) does. So I
added the ability to pass the partition parameters along in the first part of
the flow.
In terms of options for compatible changes, there are two I can see:
1. The solution suggested above. Add an additional ctor so that no existing
code breaks.
{noformat}
public Partition(Table tbl, Map<String, String> partSpec, Path location) {
this(tbl, partSpec, location, null);
}
public Partition(Table tbl, Map<String, String> partSpec, Path location,
Map<String, String> partParams) {...}
{noformat}
2. Have only the current ctor but in Hive.createPartition get the underlying
metastore.api.Partition and set the parameters to it before passing it on to
the metastoreClient.
Thoughts?
> Add export/import facilities to the hive system
> -----------------------------------------------
>
> Key: HIVE-1918
> URL: https://issues.apache.org/jira/browse/HIVE-1918
> Project: Hive
> Issue Type: New Feature
> Components: Query Processor
> Reporter: Krishna Kumar
> Attachments: HIVE-1918.patch.txt
>
>
> This is an enhancement request to add export/import features to hive.
> With this language extension, the user can export the data of the table -
> which may be located in different hdfs locations in case of a partitioned
> table - as well as the metadata of the table into a specified output
> location. This output location can then be moved over to another different
> hadoop/hive instance and imported there.
> This should work independent of the source and target metastore dbms used;
> for instance, between derby and mysql.
> For partitioned tables, the ability to export/import a subset of the
> partition must be supported.
> Howl will add more features on top of this: The ability to create/use the
> exported data even in the absence of hive, using MR or Pig. Please see
> http://wiki.apache.org/pig/Howl/HowlImportExport for these details.
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