maria-developers team mailing list archive

Thread
Date

New (by Psergey): Subqueries: cost-based choice between Materialization and IN->EXISTS transformation (90)

To: timour@xxxxxxxxxxxx
From: worklog-noreply@xxxxxxxxxxxx
Date: Sun, 28 Feb 2010 13:45:05 +0000 (UTC)
Delivered-to: worklog-db@xxxxxxxxxxxx

-----------------------------------------------------------------------
                              WORKLOG TASK
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
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
-----------------------------------------------------------------------
WorkLog (v3.5.9)