Обсуждение: misleading error message in DefineIndex

hi.

while working on virtual generated column as partition key, I found below
errmsg the constraint type is hardcoded.

            if (!found)
            {
                Form_pg_attribute att;
                att = TupleDescAttr(RelationGetDescr(rel),
                                    key->partattrs[i] - 1);
                ereport(ERROR,
                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                         errmsg("unique constraint on partitioned
table must include all partitioning columns"),
                         errdetail("%s constraint on table \"%s\"
lacks column \"%s\" which is part of the partition key.",
                                   constraint_type,
RelationGetRelationName(rel),
                                   NameStr(att->attname))));
            }

create table idxpart (a int4range, constraint xx exclude USING GIST (a
with = ), b int4range ) partition by range (b);
ERROR:  unique constraint on partitioned table must include all
partitioning columns
DETAIL:  EXCLUDE constraint on table "idxpart" lacks column "b" which
is part of the partition key.

In the example above , the primary error message "unique
constraint..." seems confusing.


--
jian
https://www.enterprisedb.com/

> On 17 Nov 2025, at 05:06, jian he <jian.universality@gmail.com> wrote:

> In the example above , the primary error message "unique
> constraint..." seems confusing.

Some of the internals does seem bleed through.  Do you want to work on a patch
for a suggestion on an improvement?  Maybe it could be possible to improve the
wording by incorporating constraint_type in some way?

--
Daniel Gustafsson

On Mon, Nov 17, 2025 at 8:52 PM Daniel Gustafsson <daniel@yesql.se> wrote:
>
> Some of the internals does seem bleed through.  Do you want to work on a patch
> for a suggestion on an improvement?  Maybe it could be possible to improve the
> wording by incorporating constraint_type in some way?
>

I have changed this ereport:

ereport(ERROR,
        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
         errmsg("unique constraint on partitioned table must include
all partitioning columns"),
         errdetail("%s constraint on table \"%s\" lacks column \"%s\"
which is part of the partition key.",
                    constraint_type, RelationGetRelationName(rel),
                    NameStr(att->attname))));

to
+                        errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                        errmsg("%s constraint on partitioned table
must include all partitioning columns", constraint_type),
+                        errdetail("%s constraint on partitioned table
\"%s\" lacks column \"%s\" which is part of the partition key.",
+                                  constraint_type,
RelationGetRelationName(rel),
+                                  NameStr(att->attname)));