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Re: Does it make sense to break a large query into separate functions?

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On 09/05/13 09:35, Merlin Moncure wrote:
[...]

More oddness -- when I wrap, say, random() with stable function, I get unique value per returned row, but same value across the set when wrapped with immutable.
[..]

That part I think I know (but, I'm often wrong!).

By saying it is immutable, you are saying that the values returned for the same set of parameters is always the same. The system looks at your immutable function that wraps random() and 'knows' that once invoked, the value returned will always be the same, so why would it want to invoke your immutable function multiple times, as it can just do that once and reuse the value returned?


Cheers,
Gavin


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