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https://issues.apache.org/jira/browse/TAJO-744?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13982221#comment-13982221
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Hyunsik Choi commented on TAJO-744:
-----------------------------------
Hi Alvin,
We already have the utility {{ExprAnnotator}} which transforms raw expressions
to annotated expressions. Annotated expression includes various information,
including data type and its origin tables. After you get an Expr instance from
tajo-algebra followed by SQLAnalyzer, you can transform the Expr instance via
{{ExprAnnotator::createEvalNode}}.
If I misunderstood your question, feel free to ask me again.
Thanks,
Hyunsik
> ALTER TABLE ADD/DROP PARTITION statement
> ----------------------------------------
>
> Key: TAJO-744
> URL: https://issues.apache.org/jira/browse/TAJO-744
> Project: Tajo
> Issue Type: New Feature
> Components: catalog
> Affects Versions: 0.9.0
> Reporter: Hyunsik Choi
> Assignee: Alvin Henrick
> Fix For: 0.9.0
>
> Attachments: TAJO-744.Henrick-140423.01.patch.txt
>
>
> Currently, Tajo does not manage partitioned directly. In Tajo, each partition
> is just a directory. For each query, a logical planner traverses matched
> directories in HDFS according to partition predicates.
> This approach is not efficient especially in the environment where the number
> of partitions are very large. It also makes partition management hard.
> Tajo should manage partitions directly by using ALTER TABLE ADD/DROP
> PARTITION statements. A number of partition entries should be stored in the
> underlying database that catalog uses.
> {code:title=Synopsis of ALTER TABLE ADD/DROP PARTITION}
> ALTER TABLE table_name [IF NOT EXISTS] ADD COLUMN PARTITION (key1 = 'val2',
> key2 = 'val2', ...) WITH ('prop_key' = 'prop_val', ...) LOCATION '...';
> ALTER TABLE table_name [IF EXISTS] DROP COLUMN PARTITION (key1
> [=|<|<=|>|>=|!=] 'val1');
> {code}
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