Re: [GENERAL] Why extract( ... from timestamp ) is not immutable?

On Mon, Jan 30, 2012 at 10:35:21AM -0800, Josh Berkus wrote:
>
> > preferably I would see extract( epoch from timestamp ) to be really
> > immutable, i.e. (in my opinion) it should treat incoming data as UTC
> > - for epoch calculation.
> > Alternatively - perhaps epoch extraction should be moved to specialized
> > function, which would have swapped mutability:
>
> We can't have functions which are immutable or not depending on their
> inputs. That way lies madness.

but this is exactly what's happening now.
extract( ... from timestamp) is marked as immutable, while in some cases
(namely when you want epoch) it should be stable because the return from
function changes.

Best regards,

depesz

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