On 28.02.26 03:04, jian he wrote:
On Wed, Feb 25, 2026 at 3:36 PM Peter Eisentraut <[email protected]> wrote:
+ if (cstate->opts.on_error == COPY_ON_ERROR_SET_NULL)
+ {
+ int attr_count = list_length(cstate->attnumlist);
+
+ cstate->domain_with_constraint = palloc0_array(bool, attr_count);
Maybe add a comment for this block to explain that you are collecting
information about domains for later.
Here is what I came up with:
+ /*
+ * When data type conversion fails and ON_ERROR is SET_NULL, we need
+ * ensure that input column allows NULL value, ExecConstraints will
+ * cover most of the cases, however it does not vertify domain
+ * constraints. Therefore, for constrained domains, NULL value check
+ * must be performed during the initial string-to-datum conversion
+ * (see CopyFromTextLikeOneRow).
+ */
+ /*
+ * If the column type is a constrained domain, an additional
+ * InputFunctionCallSafe may be needed to raise error for
+ * domain constraint violation.
+ */
Why "may be needed"? Is it sometimes not needed? Why, under what
circumstances?
I changed the comments to:
+ /*
+ * For constrained domain types, we need an additional
+ * InputFunctionCallSafe to ensure that an error is thrown if
+ * the domain constraint rejects NULL.
+ */
The subsequent error message writes "domain ... does not allow null
values", but AFAICT a domain input failure could also be due to a check
constraint failure? How would that be handled? The flow here is a bit
confusing.
create domain d3 as int check (value is not null);
create table t(a d3);
src4=# copy t1 from stdin (on_error set_null);
Enter data to be copied followed by a newline.
End with a backslash and a period on a line by itself, or an EOF signal.
\N
\.
ERROR: domain d1 does not allow null values
DETAIL: ON_ERROR SET_NULL cannot be applied because column "a"
(domain d1) does not accept null values.
CONTEXT: COPY t1, line 1, column a: null input
It's more about whether all domain constraints allow a NULL value,
In this context, the domain constraint is a CHECK constraint.
``InputFunctionCallSafe(&in_functions[m], NULL,``
this check whether a NULL value is allowed for this domain.
ExecConstraints does not handle domain constraints, so this is needed.
The error message:
``errmsg("domain %s does not allow null values",``
should be fine?
All other suggestions have been incorporated into v24.
Thanks, committed.
