[postgis-devel] Another Data Point

Mark Cave-Ayland mark.cave-ayland at siriusit.co.uk
Wed Jan 21 09:11:07 PST 2009


Paul Ramsey wrote:

> Interesting! The Shark only samples for about 20 seconds, so I only
> got the first 10% or so of the run, and the biggest user in that time
> period memcpy'ing in LWGEOM_accum (postgis) and
> advance_transition_function (pgsql). So we are spending a non-trivial
> amount of time just accumulating the input...
> 
> P

Yeah, I think this came out of some of Regina's observations earlier 
when she was looking at changing the function; constantly accumulating 
onto the end of an array is slow since we repalloc() the memory and 
rebuild the entire type each time through...


ATB,

Mark.

-- 
Mark Cave-Ayland
Sirius Corporation - The Open Source Experts
http://www.siriusit.co.uk
T: +44 870 608 0063



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