Re: [PATCH] psql: add \dcs to list all constraints

On 2026-Jan-20, Tatsuro Yamada wrote:

> The error in the query has been fixed, and the execution times were
> measured again.
> As a result, there was no significant difference in execution time
> between the two queries (see the attached test_result2.txt).
> When comparing the cost of the top node, the original query has a
> slightly lower cost, so I decided to keep it as is.

Yeah, these results match my own tests -- the query I proposed is a bit
slower.  Not by a lot, but measurably so.  (I did ran my disk full by
running pgbench with the two queries in separate files and the one
million constraints; temp files for sort are quite large.  My query is
pretty consistently reported to be slower than the other anyway.)

>                    List of constraints
>  Schema | Table |   Type    |            Name
> --------+-------+-----------+----------------------------
>  public | con_c | NOT NULL  | con_c_primary_col_not_null
>  public | con_c | PK        | con_c_pkey
>  public | con_p | CHECK     | con_p_check_col_check
>  public | con_p | EXCLUSION | con_p_exclusion
>  public | con_p | FK        | con_p_foreign_col_fkey
>  public | con_p | NOT NULL  | con_p_notnull_col_not_null
>  public | con_p | NOT NULL  | con_p_primary_col_not_null
>  public | con_p | PK        | con_p_pkey
>  public | con_p | TRIGGER   | con_p_trigger
>  public | con_p | UNIQUE    | con_p_unique_col_key
> (10 rows)
> 
> What do you think?

Looks good.  I think the constraint types ought to be lower-case and
fully spelled out, with not-null having an hyphen as discussed
elsewhere (though I couldn't find the reference), so
	not-null
	primary key
	exclusion
	check
	foreign key
	unique
	trigger

I wonder if we should mark temporal constraints especially.  (So
"temporal primary key", etc).  Without thinking too much about it, my
impression is that it'd be useful.

I didn't look at the patch closer, apologies.

Thanks

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/
Officer Krupke, what are we to do?
Gee, officer Krupke, Krup you! (West Side Story, "Gee, Officer Krupke")