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Problem with hierarchy-walker optimization #208

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GoogleCodeExporter opened this issue Mar 16, 2015 · 2 comments
Closed

Problem with hierarchy-walker optimization #208

GoogleCodeExporter opened this issue Mar 16, 2015 · 2 comments

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@GoogleCodeExporter
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The following query:

type-of($topic_, $type_) :- { 
  instance-of($topic_, $type_) 
| 
  instance-of($topic_, $type), 
  type-of($type, $type_) 
}.

select $TOPIC from
type-of($TOPIC, %TYPE%), $TOPIC = %TOPIC%?

produces results as though the final ($TOPIC = ...) clause were not 
present. If the hierarchy-walker is turned off the problem disappears.

Original issue reported on code.google.com by lar...@gmail.com on 18 Feb 2010 at 11:39

@GoogleCodeExporter
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This issue was closed by revision r903.

Original comment by lar...@gmail.com on 18 Feb 2010 at 12:31

  • Changed state: Fixed

@GoogleCodeExporter
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This turned out to be fairly involved. Basically, if input to the 
hierarchy-walker 
was a single row, and that row had both input variables bound, and the one 
chosen as 
the goal column was a variable (and not a constant) *then* the output would be 
all 
valid values instead of the single value the output column was bound to.

Solved in revision 903. A test case has been added.

Original comment by lar...@gmail.com on 18 Feb 2010 at 12:32

  • Changed state: Verified

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