Switch from stable to immutable

[AntoineAugusti]

I don't see why we set the volatility of all UDFs to stable instead of immutable here: https://github.com/PeriscopeData/redshift-udfs/blob/master/udf_harness.rb#L108

The Redshift documentation says this:

http://docs.aws.amazon.com/fr_fr/redshift/latest/dg/r_CREATE_FUNCTION.html

[mopatches]

Hello @AntoineAugusti! You make a good point!

Currently the UDF harness is pretty simple and doesn't differentiate. Setting everything to volatile lets if someone makes a UDF with non-stable output (e.g. using random()) and have it work just fine.

If we switch to stable as the default, we'd need a way for folks to set their UDF as volatile in the definition.

[AntoineAugusti]

If we switch to stable as the default, we'd need a way for folks to set their UDF as volatile in the definition.

The current default is stable :)

But I agree, if we switch to immutable by default, we need a way to let people overwrite the volatility on specific UDFs