Re: Boolean partitions syntax

On 10 April 2018 at 23:13, Kyotaro HORIGUCHI
 wrote:
> Note: This is not intended to be committed this time but just for
> information.
>
> At Tue, 10 Apr 2018 10:34:27 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI  wrote in <20180410.103427.244142052.horiguchi.kyotaro@lab.ntt.co.jp>
>> Just adding negation would work as a_expr is doing.
>>
>> >             | '-' a_expr                    %prec UMINUS
>> >                 { $$ = doNegate($2, @1); }
>
> a_expr fits partbound_datum_list as is but it cannot sit
> side-by-side with MAX/MINVALUE at all. However c_expr can if
> columnref is not excluded. The attached patch does that and
> partition bound accepts the following syntax. (I didn't see the
> transform side at all)
>
> create table p2c1 partition of p2 for values from (log(1000),0+1,0/1) to (10, 10, ('1'||'0')::int);

I imagined this would have had a check for volatile functions and some
user-friendly error message to say partition bounds must be immutable,
but instead, it does:

postgres=# create table d_p1 partition of d for values in (Random());
ERROR:  specified value cannot be cast to type double precision for column "d"
LINE 1: create table d_p1 partition of d for values in (Random());
                                                        ^
DETAIL:  The cast requires a non-immutable conversion.
HINT:  Try putting the literal value in single quotes.

For inspiration, maybe you could follow the lead of CREATE INDEX:

postgres=# create index on d ((random()));
ERROR:  functions in index expression must be marked IMMUTABLE

-- 
 David Rowley                   http://www.2ndQuadrant.com/
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