Horton

Re: ALTER COLUMN ... SET EXPRESSION to alter stored generated column's expression

amul sul <sulamul@gmail.com>

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From: Amul Sul <sulamul@gmail.com>
To: Peter Eisentraut <peter@eisentraut.org>
Cc: Robert Haas <robertmhaas@gmail.com>, Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, Vaibhav Dalvi <vaibhav.dalvi@enterprisedb.com>, pgsql-hackers@postgresql.org
Date: 2023-11-15T12:26:12Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. ALTER TABLE command to change generation expression

  2. Refactor: separate function to find all objects depending on a column

  3. Turn AT_PASS_* macros into an enum

On Wed, Nov 15, 2023 at 5:09 PM Peter Eisentraut <peter@eisentraut.org>
wrote:

> On 14.11.23 11:40, Amul Sul wrote:
> > Please have a look at the attached version, updating the syntax to have
> "AS"
> > after EXPRESSION and other changes suggested previously.
>
> The code structure looks good to me now.
>

Thank you for your review.


>
> Question: Why are you using AT_PASS_ADD_OTHERCONSTR?  I don't know if
> it's right or wrong, but if you have a specific reason, it would be good
> to know.
>

I referred to ALTER COLUMN DEFAULT and used that.



> I think ATExecSetExpression() needs to lock pg_attribute?  Did you lose
> that during the refactoring?
>

I have removed that intentionally since we were not updating anything in
pg_attribute like ALTER DROP EXPRESSION.


>
> Tiny comment: The error message in ATExecSetExpression() does not need
> to mention "stored", since it would be also applicable to virtual
> generated columns in the future.
>

I had to have the same thought, but later decided when we do that
virtual column thing, we could simply change that. I am fine to do that
change
now as well, let me know your thought.


> Documentation additions in alter_table.sgml should use one-space indent
> consistently.  Also, "This form replaces expression" is missing a "the"?
>

Ok, will fix that.

Regards,
Amul