Re: Domain breakage

This is now fixed in CVS, I believe by Tom's recent commit:test=> create domain tint as int;CREATE DOMAINtest=> select
1::tint> (-1); ?column?---------- t(1 row)test=> select  1::tint > (-1)::tint; ?column?---------- t(1 row)
 

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Tom Lane wrote:
> Here's a fun one: in 7.3 or CVS tip, try
> 
> regression=# create domain tint as int;
> CREATE DOMAIN
> regression=# select  1::tint > (-1);
>  ?column?
> ----------
>  t
> (1 row)
> 
> regression=# select  1::tint > (-1)::tint;
>  ?column?
> ----------
>  f
> (1 row)
> 
> How's that again?  Well, when you dig into it you find that the second
> case is invoking the OID greater-than operator (oidgt), which does
> unsigned comparison.  Why is it picking oidgt and not int4gt,
> considering that the domain is based on int4?  Well, the problem is that
> the domain type is considered binary-compatible with both int4 and oid;
> there isn't any stronger connection to the base type than there is to
> any other type that's binary-compatible with the domain.  So
> oper_select_candidate gets down to its third tiebreaker, preferred-type
> status ... and guess what, OID is a preferred type in its category while
> int4 is not preferred in its category.
> 
> I suspect that the most workable fix for this is to reduce all the input
> typeids to base types before we start the operator or function type
> resolution routines.  However, this would completely destroy any hope of
> making domain-specific operators.
> 
> (I'm also reminded once again that I don't like the preferred-type
> heuristics.  They're too likely to produce surprising choices.)
> 
> A different line of attack would be to modify the operator/function
> resolution rules to take account of domain relationships explicitly,
> making the binding of domain to base type stronger than mere binary
> equivalence.  But I'm not clear how that might work.
> 
> Any ideas?
> 
>             regards, tom lane
> 
> 
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