Feature Requests item #2704025, was opened at 2009-03-22 20:42
Message generated for change (Settings changed) made by mr-meltdown
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Category: None
Group: None
Status: Open
Priority: 5
Private: No
Submitted By: Stefan de Konink (skinkie)
Assigned to: Niels Nes (nielsnes)
>Summary: SQL: dynamic selectivity optimiser required

Initial Comment:
Using the OSM dataset I noticed there is a significant difference in the 
following queries:

select * from way_tags where way = 9168360 and k = 'created_by';
Timer   10583.483 msec 2 rows

vs

select * from way_tags where k = 'created_by' and  way = 9168360;
Timer     331.086 msec 2 rows

(this is not about hot/cold performance, the next try of the first query 
results in 10286.816 msec)

Niels noted that this could be solved automatically using a dynamic selectivity 
optimiser. I first noticed this issue using delete from.

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Comment By: Martin Kersten (mlkersten)
Date: 2009-03-22 20:51

Message:
such an optimizer is a feature request, rather then a bug.

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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=482471&aid=2704025&group_id=56967

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