Re: support fast default for domain with constraints

On 2026-03-11 We 6:34 AM, Viktor Holmberg wrote:
> I’ve been burned my this issue in the past so would be great if this
> could get in.
>
> +/*
> + * DomainHasVolatileConstraints --- check if a domain has constraints
> with
> + * volatile expressions
> + *
> + * Returns true if the domain has any constraints at all. If
> have_volatile
> + * is not NULL, also checks whether any CHECK constraint contains a
> volatile
> + * expression and sets *have_volatile accordingly.
> + *
> + * The caller must initialize *have_volatile before calling (typically to
> + * false). This function only ever sets it to true, never to false.
> + *
> + * This is defined to return false, not fail, if type is not a domain.
> + */
> +bool
> +DomainHasVolatileConstraints(Oid type_id, bool *have_volatile)
>
> Call it CheckDomainConstraints or something instead? IMO it's confusing
> the have it not return what it's called.
>
> Also, it'd make it more self-contained and thus safer to initialise
> have_volatile to false.
>
> + if (typentry->domainData != NULL)
> + {
> + if (have_volatile)
> + {
> + foreach_node(DomainConstraintState, constrstate,
> + typentry->domainData->constraints)
> + {
> + if (constrstate->constrainttype == DOM_CONSTRAINT_CHECK &&
> + contain_volatile_functions((Node *) constrstate->check_expr))
> + {
> + *have_volatile = true;
> + break;
> + }
> + }
> + }
> +
> + return true;
> + }
> +
> + return false;
> +}
> Could simplify the code by doing an early return if domainData == NULL?
> (same with have_volatile below)

I think it's cleaner just to modify the existing function with an extra
parameter, which the existing callers will pass as NULL.

>
>
>
>
> Would be nice to test domains with both volatile and non-volatile checks.
> Also, perhaps virtual generated columns could use a test?
>
>

Also added some tests.

cheers

andrew

--
Andrew Dunstan
EDB:https://www.enterprisedb.com