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New (by Igor): Implement UNION ALL without usage of a temporary table (44)

To: bo@xxxxxxxxxxxx
From: worklog-noreply@xxxxxxxxxxxx
Date: Fri, 14 Aug 2009 08:31:14 +0300 (EEST)
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                              WORKLOG TASK
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TASK...........: Implement UNION ALL without usage of a temporary table
CREATION DATE..: Fri, 14 Aug 2009, 08:31
SUPERVISOR.....: Bothorsen
IMPLEMENTOR....: 
COPIES TO......: Monty, Psergey
CATEGORY.......: Client-BackLog
TASK ID........: 44 (http://askmonty.org/worklog/?tid=44)
VERSION........: Benchmarks-3.0
STATUS.........: Un-Assigned
PRIORITY.......: 60
WORKED HOURS...: 0
ESTIMATE.......: 0 (hours remain)
ORIG. ESTIMATE.: 0

PROGRESS NOTES:



DESCRIPTION:

Currently when any union operation is executed the rows received from its
operands are always sent to a temporary table. Meanwhile for a UNION ALL
operation that is used at the top level of a query without an ORDER BY clause it
is not necessary. In this case the rows could be sent directly to the client.
The goal of this task  is to provide such an implementation of UNION ALL
operation that would not use temporary table at all in certain, most usable cases. 


ESTIMATED WORK TIME

ESTIMATED COMPLETION DATE
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