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https://issues.apache.org/jira/browse/HIVE-4838?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13717716#comment-13717716
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Brock Noland commented on HIVE-4838:
------------------------------------
Hey,
Yes I have. I'll upload an updated patch here in a few minutes. The current
code is using this static code because by using java serialization there is no
way to pass any "context" information down to the class when the read/write
methods are being called. In the new patch I define my own read/write methods
(example below).
{noformat}
public void read(MapJoinObjectSerDeContext context, ObjectInputStream in,
Writable container)
throws IOException, SerDeException {
{noformat}
and use those to serialize/deserialize the objects. Specifically in the new
patch MapJoinRowContainer.read/write, MapJoinTableContainerSerDe.load/persist
and MapJoinKey.read/write will be interesting.
> Refactor MapJoin HashMap code to improve testability and readability
> --------------------------------------------------------------------
>
> Key: HIVE-4838
> URL: https://issues.apache.org/jira/browse/HIVE-4838
> Project: Hive
> Issue Type: Bug
> Reporter: Brock Noland
> Assignee: Brock Noland
> Attachments: HIVE-4838.patch, HIVE-4838.patch
>
>
> MapJoin is an essential component for high performance joins in Hive and the
> current code has done great service for many years. However, the code is
> showing it's age and currently suffers from the following issues:
> * Uses static state via the MapJoinMetaData class to pass serialization
> metadata to the Key, Row classes.
> * The api of a logical "Table Container" is not defined and therefore it's
> unclear what apis HashMapWrapper
> needs to publicize. Additionally HashMapWrapper has many used public methods.
> * HashMapWrapper contains logic to serialize, test memory bounds, and
> implement the table container. Ideally these logical units could be seperated
> * HashTableSinkObjectCtx has unused fields and unused methods
> * CommonJoinOperator and children use ArrayList on left hand side when only
> List is required
> * There are unused classes MRU, DCLLItemm and classes which duplicate
> functionality MapJoinSingleKey and MapJoinDoubleKeys
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