hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Brock Noland (JIRA)" <>
Subject [jira] [Commented] (HIVE-4838) Refactor MapJoin HashMap code to improve testability and readability
Date Thu, 01 Aug 2013 15:13:52 GMT


Brock Noland commented on HIVE-4838:

Hey can you explain a little bit more? We aren't writing out the metadata per-key or anything
like that, we are passing the metadata down into new read/write methods. AFAICT the current
approach did the static stuff because they were using the Externalizable interface which didn't
not allow any push-down metadata during seralization or deserialization. If you look at MapJoinTableContainer
read and write in the new patch you'll see us pushing the metadata (called context) down into
the *new* read/write methods and the corresponding read/write methods are not serializing
that metadata.
> Refactor MapJoin HashMap code to improve testability and readability
> --------------------------------------------------------------------
>                 Key: HIVE-4838
>                 URL:
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Brock Noland
>            Assignee: Brock Noland
>         Attachments: HIVE-4838.patch, HIVE-4838.patch, 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

This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see:

View raw message