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Sylvain Lebresne commented on CASSANDRA-8374:
---------------------------------------------
bq. I like the per-arg (and return type) ALLOW NULL.
Fair enough, but do you have any better argument? I mean, I get that it's more
flexible in theory, but I can see 90% of usage sticking to the default (of no
nulls anywhere). And for the rare case where you do want to handle null, I
doesn't feel like handling it for every argument is a big deal. On the other
side, having it global is simpler (conceptually, in term of documentation, of
code etc...). So to clarify, when I say "Not a terribly strong preference", I
mean "I'm -1 on per-arg, but if there is a strong conscensus that it's actually
very useful, I won't fight it too much".
As a side note, I'm not sure having it on the return type really make sense at
all: not sure what we could do if there is no {{ALLOW NULL}} and the method
does end up returning a null.
> Better support of null for UDF
> ------------------------------
>
> Key: CASSANDRA-8374
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8374
> Project: Cassandra
> Issue Type: Bug
> Reporter: Sylvain Lebresne
> Assignee: Robert Stupp
> Fix For: 3.0
>
>
> Currently, every function needs to deal with it's argument potentially being
> {{null}}. There is very many case where that's just annoying, users should be
> able to define a function like:
> {noformat}
> CREATE FUNCTION addTwo(val int) RETURNS int LANGUAGE JAVA AS 'return val + 2;'
> {noformat}
> without having this crashing as soon as a column it's applied to doesn't a
> value for some rows (I'll note that this definition apparently cannot be
> compiled currently, which should be looked into).
> In fact, I think that by default methods shouldn't have to care about
> {{null}} values: if the value is {{null}}, we should not call the method at
> all and return {{null}}. There is still methods that may explicitely want to
> handle {{null}} (to return a default value for instance), so maybe we can add
> an {{ALLOW NULLS}} to the creation syntax.
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