[postgis-devel] What's the difference between geom_accum and built in postgresql array_append

Paul Ramsey pramsey at cleverelephant.ca
Wed Aug 6 11:18:05 PDT 2008


I'm pretty sure that code dates back to dblasby, so he'd have to weigh
in on the why's and wherefore's.  strk would have just been
maintaining what was there.

P.

On Wed, Aug 6, 2008 at 8:25 AM, Kevin Neufeld <kneufeld at refractions.net> wrote:
> I could be way off on this, but I suspect the reason is because it looks
> like array_append was introduced in PostgreSQL in 7.1, after or about the
> same time PostGIS was born.
>
> -- Kevin
>
> Obe, Regina wrote:
>>
>> I was trying to take a stab at understanding the postgis internal
>> workings and one question that has always puzzled me is
>>
>> Why are we using a postgis geom_accum function instead of the built in
>> PostgreSQL array_append function to define our aggregates.  I did a
>> couple of simple tests and the timings always seem pretty much exactly
>> the same.
>>
>> The only thought I could think of why this was done was
>> 1) Its easier to debug the internal workings of the array
>> 2) and its possible to internally throw PostGIS specific errors
>>
>> Does that about sum it up or are there other reasons I am missing?
>>
>> Thanks,
>> Regina
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