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WORKLOG TASK
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TASK...........: Subqueries: cost-based choice between Materialization and
IN->EXISTS
transformation
CREATION DATE..: Sun, 28 Feb 2010, 13:45
SUPERVISOR.....: Monty
IMPLEMENTOR....:
COPIES TO......: Igor, Psergey, Timour
CATEGORY.......: Server-RawIdeaBin
TASK ID........: 90 (http://askmonty.org/worklog/?tid=90)
VERSION........: Server-5.3
STATUS.........: Un-Assigned
PRIORITY.......: 60
WORKED HOURS...: 0
ESTIMATE.......: -1 (hours remain)
ORIG. ESTIMATE.: 0
PROGRESS NOTES:
DESCRIPTION:
For uncorrelated IN subqueries that can't be converted to semi-joins it is
necessary to make a cost-based choice between IN->EXISTS and Materialization
strategies.
Both strategies handle two cases:
1. A simple case w/o NULLs handling
2. Handling NULLs.
This WL is about making cost-based decision for #1.
ESTIMATED WORK TIME
ESTIMATED COMPLETION DATE
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WorkLog (v3.5.9)
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