Re: Adding support for Default partition in partitioning

On Sat, Jun 3, 2017 at 2:11 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> + errmsg("default partition contains row(s)
> that would overlap with partition being created")));
>
> It doesn't really sound right to talk about rows overlapping with a
> partition. Partitions can overlap with each other, but not rows.
> Also, it's not really project style to use ambiguously plural forms
> like "row(s)" in error messages. Maybe something like:
>
> new partition constraint for default partition \"%s\" would be
> violated by some row
>

Partition constraint is implementation detail here. We enforce
partition bounds through constraints and we call such constraints as
partition constraints. But a user may not necessarily understand this
term or may interpret it different. Adding "new" adds to the confusion
as the default partition is not new. My suggestion in an earlier mail
was ""default partition contains rows that conflict with the partition
bounds of "part_xyz"", with a note that we should use a better word
than "conflict". So, Jeevan seems to have used overlap, which again is
not correct. How about "default partition contains row/s which would
fit the partition "part_xyz" being created or attached." with a hint
to move those rows to the new partition's table in case of attach. I
don't think hint would be so straight forward i.e. to create the table
with SELECT INTO and then ATTACH.

What do you think?

Also, the error code ERRCODE_CHECK_VIOLATION, which is an "integrity
constraint violation" code, seems misleading. We aren't violating any
integrity here. In fact I am not able to understand, how could adding
an object violate integrity constraint. The nearest errorcode seems to
be ERRCODE_INVALID_OBJECT_DEFINITION, which is also used for
partitions with overlapping bounds.

--
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company