Re: bug: virtual generated column can be partition key
| От | Ashutosh Bapat |
|---|---|
| Тема | Re: bug: virtual generated column can be partition key |
| Дата | |
| Msg-id | CAExHW5vYwW1OLTt1-+qEOWA9othNhytrxLnLUoT=JL9jk-3vxQ@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: bug: virtual generated column can be partition key (jian he <jian.universality@gmail.com>) |
| Ответы |
Re: bug: virtual generated column can be partition key
|
| Список | pgsql-hackers |
Sorry I missed this email while sending the patches - our emails crossed in the air.
On Tue, Apr 22, 2025 at 2:15 PM jian he <jian.universality@gmail.com> wrote:
On Tue, Apr 22, 2025 at 3:02 PM jian he <jian.universality@gmail.com> wrote:
> Other than that, it looks good to me for fixing this bug.
The error message seems not that intuitive.
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint
GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE
((gtest_part_key));
+ERROR: cannot use generated column in partition key
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((gtest_par...
+ ^
+DETAIL: Column "f3" is a generated column.
Yes. It's not apparent where does f3 appear in the partition key, to a lay users. Users who explicitly use whole row expression in a partition key, would know that a whole row expression contains all columns. And the error location points to the whole-row reference. So the current state isn't that bad.
with the attached patch. now,
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint
GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE
((gtest_part_key));
ERROR: cannot use generated column in partition key
LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((gtest_par...
^
DETAIL: Generated column "f3" is part of the partition key of
relation "gtest_part_key"
The DETAIL here is just mentioning what's already known from the command, so the change in the DETAIL may not be useful.
If I understand your intention correctly, we have to mention something to the effect "partition key expression contains a whole-row reference which in turn contains a generated column." But that might be too verbose.
Best Wishes,
Ashutosh Bapat
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