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Posted to dev@hive.apache.org by "Carl Steinbach (JIRA)" <ji...@apache.org> on 2012/05/06 03:25:48 UTC
[jira] [Created] (HIVE-3005) Query containing "LIMIT 0" clause
should skip execution phase
Carl Steinbach created HIVE-3005:
------------------------------------
Summary: Query containing "LIMIT 0" clause should skip execution phase
Key: HIVE-3005
URL: https://issues.apache.org/jira/browse/HIVE-3005
Project: Hive
Issue Type: Improvement
Components: Query Processor
Reporter: Carl Steinbach
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[jira] [Assigned] (HIVE-3005) Skip execution phase for queries that
contain "LIMIT 0" clause
Posted by "Carl Steinbach (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HIVE-3005?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Carl Steinbach reassigned HIVE-3005:
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Assignee: Shreepadma Venugopalan
> Skip execution phase for queries that contain "LIMIT 0" clause
> --------------------------------------------------------------
>
> Key: HIVE-3005
> URL: https://issues.apache.org/jira/browse/HIVE-3005
> Project: Hive
> Issue Type: Improvement
> Components: Query Processor
> Reporter: Carl Steinbach
> Assignee: Shreepadma Venugopalan
>
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[jira] [Commented] (HIVE-3005) Query containing "LIMIT 0" clause
should skip execution phase
Posted by "Carl Steinbach (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HIVE-3005?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13269099#comment-13269099 ]
Carl Steinbach commented on HIVE-3005:
--------------------------------------
Executing a query that contains a "LIMIT 0" clause is a trick that some clients (e.g. ODBC clients) employ in order to generate a result set without incurring the cost of actually executing the query. Unfortunately, this trick doesn't work with Hive:
{noformat}
hive> SELECT key FROM SRC LIMIT 0;
SELECT key FROM SRC LIMIT 0;
Total MapReduce jobs = 1
Launching Job 1 out of 1
Number of reduce tasks is set to 0 since there's no reduce operator
Execution log at: /tmp/carl/carl_20120505182828_a5405bcb-c156-4572-b2d8-eda2cc199a14.log
Job running in-process (local Hadoop)
Hadoop job information for null: number of mappers: 0; number of reducers: 0
2012-05-05 18:28:35,999 null map = 100%, reduce = 0%
Ended Job = job_local_0001
Execution completed successfully
Mapred Local Task Succeeded . Convert the Join into MapJoin
OK
{noformat}
> Query containing "LIMIT 0" clause should skip execution phase
> -------------------------------------------------------------
>
> Key: HIVE-3005
> URL: https://issues.apache.org/jira/browse/HIVE-3005
> Project: Hive
> Issue Type: Improvement
> Components: Query Processor
> Reporter: Carl Steinbach
>
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[jira] [Updated] (HIVE-3005) Skip execution phase for queries that
contain "LIMIT 0" clause
Posted by "Carl Steinbach (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HIVE-3005?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Carl Steinbach updated HIVE-3005:
---------------------------------
Summary: Skip execution phase for queries that contain "LIMIT 0" clause (was: Query containing "LIMIT 0" clause should skip execution phase)
> Skip execution phase for queries that contain "LIMIT 0" clause
> --------------------------------------------------------------
>
> Key: HIVE-3005
> URL: https://issues.apache.org/jira/browse/HIVE-3005
> Project: Hive
> Issue Type: Improvement
> Components: Query Processor
> Reporter: Carl Steinbach
>
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