[postgis-users] Scale without translate?

[Mark Leslie]

The precise answer is "probably".  The Centroid is defined as immutable,
so postgresql knows that the same answer will be obtained for the same
arguments and knows that it can cache the results.  When/how/if it
chooses to caches I couldn't say.
Mark

Rob Agar wrote:
> Bruce Rindahl wrote:
>> SELECT translate(
>> scale(
>> translate(the_geom,-x(centroid(the_geom)),-y(centroid(the_geom)))
>> ,myScale)
>> ,x(centroid(the_geom)),y(centroid(the_geom)))
> 
> on a side point, is the postgresql optimizer smart enough not to call
> centroid() four times in this case?
> 
> Rob
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