Feedback-ID: i76984098:Fastmail
Message-ID: <301832e8-a3d7-46f5-9db5-691b71eee9ac@aklaver.com>
Date: Sun, 30 Nov 2025 19:23:12 -0800
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: Check whether a NOT NULL check constraint has been validated
From: Adrian Klaver <adrian.klaver@aklaver.com>
To: Stuart Campbell <stuart.campbell@ridewithvia.com>,
 pgsql-general@postgresql.org
References: <CAAZ6SnyOmabkioC3n8GCk5dWQsx57pCSiZy_x1JEOrY7aejxaA@mail.gmail.com>
 <1b930bcc-16f4-4c97-93f8-a21d314ba373@aklaver.com>
Content-Language: en-US
In-Reply-To: <1b930bcc-16f4-4c97-93f8-a21d314ba373@aklaver.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Archived-At: <https://www.postgresql.org/message-id/301832e8-a3d7-46f5-9db5-691b71eee9ac%40aklaver.com>
Precedence: bulk

On 11/30/25 19:07, Adrian Klaver wrote:
> On 11/30/25 16:59, Stuart Campbell wrote:
>> Hello,
>>
>> I have several NOT NULL check constraints in my schema that were 
>> originally added as NOT VALID. I would like to determine whether they 
>> have all since been validated, or not.
>>
>> I thought maybe pg_constraint.convalidated might help, but it seems 
>> like the version of Postgres I'm using (16) doesn't store not null 
>> constraints in that table. And even in later versions, maybe it 
>> doesn't hold the information I need.
>>
>> Is there another way to discover this?
> 
> 1) Select count(*) from <table> where <col> IS NULL;
> 
> 2) From here
> 
> https://www.postgresql.org/docs/current/sql-altertable.html#SQL- 
> ALTERTABLE-NOTES
> 
> ALTER TABLE <table> VALIDATE CONSTRAINT <constraint_name>;
> 
> As described:
> 
> ". Once the constraint is in place, no new violations can be inserted, 
> and the existing problems can be corrected at leisure until VALIDATE 
> CONSTRAINT finally succeeds."

Realized I was looking at current docs and I should be looking at your 
version

 From the 16 version of the docs:

"This form adds a new constraint to a table using the same constraint 
syntax as CREATE TABLE, plus the option NOT VALID, which is currently 
only allowed for foreign key and CHECK constraints."

Now I am not sure what you did.

Are you saying you used a CHECK constraint to check for NULL values?

If so then pg_constraint.convalidated would work.

If not are you sure you are on Postgres 16?


> 
>>
>> This communication and any attachments may contain confidential 
>> information and are intended to be viewed only by the intended 
>> recipients. If you have received this message in error, please notify 
>> the sender immediately by replying to the original message and then 
>> delete all copies of the email from your systems.
>>
>>
> 
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com