[postgis-devel] iscachable

[Mark Cave-Ayland]

> -----Original Message-----
> From: strk at refractions.net [mailto:strk at refractions.net] 
> Sent: 14 January 2005 16:34
> To: PostGIS Development Discussion; Mark Cave-Ayland
> Subject: Re: [postgis-devel] iscachable
> 
> 
> I've committed a first adaption to the new way of
> specifiying CREATE FUNCTION attributes.
> Will anyone review it ?
> 
> When a with() clause was already specified I left it
> there after a -- comment.
> 
> Often I added the IMMUTABLE key.
> In very few cases I used STABLE.
> 
> I didn't know what to do with versioning funx
> and 'internal' funx (geometry_analyze, postgis_gist_sel, 
> LWGEOM_gist_*) so I left them with no specification, 
> suggestion welcome.
> 
> --strk;


Hi strk,

As I understand from the documentation, I think it's mainly to do with
folding the results of functions down into constants where possible when
creating a query plan. So I'd imagine that since the internal functions are
called directly, this would not be an issue, but would stand to be
corrected. This is reading between the lines from
http://www.postgresql.org/docs/7.4/static/sql-createfunction.html.


Kind regards,

Mark.

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