Thread: Re: How to get a notification

On 2/5/25 23:21, Igor Korot wrote:
> Hi, ALL,
> In my code I'm running following:
> 
>              queries.push_back( L"CREATE FUNCTION
> __watch_schema_changes() RETURNS event_trigger LANGUAGE plpgsql AS $$
> BEGIN NOTIFY tg_tag; END; $$;" );
>              queries.push_back( L"CREATE EVENT TRIGGER
> schema_change_notify ON ddl_command_end WHEN TAG IN(\'CREATE TABLE\',
> \'ALTER TABLE\', \'DROP TABLE\', \'CREATE INDEX\', \'DROP INDEX\')
> EXECUTE PROCEDURE __watch_schema_changes();" );
> 
> My questions are:
> 1 Is there a better way to get notification about CREATE/ALTER/DROP TABLE?

An alternate solution:

https://www.pgaudit.org/

Whether it is better or not is something you will need to decide.

> 2. How do I receive notification abut the event with the object name?

Use information from here?:

https://www.postgresql.org/docs/current/functions-event-triggers.html#PG-EVENT-TRIGGER-DDL-COMMAND-END-FUNCTIONS

> 
> Thank you.
> 
> 

-- 
Adrian Klaver
adrian.klaver@aklaver.com

Hi, Adrian,

On Fri, Feb 7, 2025 at 11:07 AM Adrian Klaver <adrian.klaver@aklaver.com> wrote:
>
> On 2/5/25 23:21, Igor Korot wrote:
> > Hi, ALL,
> > In my code I'm running following:
> >
> >              queries.push_back( L"CREATE FUNCTION
> > __watch_schema_changes() RETURNS event_trigger LANGUAGE plpgsql AS $$
> > BEGIN NOTIFY tg_tag; END; $$;" );
> >              queries.push_back( L"CREATE EVENT TRIGGER
> > schema_change_notify ON ddl_command_end WHEN TAG IN(\'CREATE TABLE\',
> > \'ALTER TABLE\', \'DROP TABLE\', \'CREATE INDEX\', \'DROP INDEX\')
> > EXECUTE PROCEDURE __watch_schema_changes();" );
> >
> > My questions are:
> > 1 Is there a better way to get notification about CREATE/ALTER/DROP TABLE?
>
> An alternate solution:
>
> https://www.pgaudit.org/
>
> Whether it is better or not is something you will need to decide.
>
> > 2. How do I receive notification abut the event with the object name?
>
> Use information from here?:
>
> https://www.postgresql.org/docs/current/functions-event-triggers.html#PG-EVENT-TRIGGER-DDL-COMMAND-END-FUNCTIONS

Thx for the link
So basically all I need to do is to call

SELECT pg_event_trigger_ddl_commands ()

right?

In both ODBC amd libpq interfaces?

Thank you.



>
> >
> > Thank you.
> >
> >
>
> --
> Adrian Klaver
> adrian.klaver@aklaver.com
>

On 2/7/25 11:02 AM, Igor Korot wrote:
> Hi, Adrian,
> 
> On Fri, Feb 7, 2025 at 11:07 AM Adrian Klaver <adrian.klaver@aklaver.com> wrote:
>>
>> On 2/5/25 23:21, Igor Korot wrote:
>>> Hi, ALL,
>>> In my code I'm running following:
>>>
>>>               queries.push_back( L"CREATE FUNCTION
>>> __watch_schema_changes() RETURNS event_trigger LANGUAGE plpgsql AS $$
>>> BEGIN NOTIFY tg_tag; END; $$;" );
>>>               queries.push_back( L"CREATE EVENT TRIGGER
>>> schema_change_notify ON ddl_command_end WHEN TAG IN(\'CREATE TABLE\',
>>> \'ALTER TABLE\', \'DROP TABLE\', \'CREATE INDEX\', \'DROP INDEX\')
>>> EXECUTE PROCEDURE __watch_schema_changes();" );
>>>
>>> My questions are:
>>> 1 Is there a better way to get notification about CREATE/ALTER/DROP TABLE?
>>
>> An alternate solution:
>>
>> https://www.pgaudit.org/
>>
>> Whether it is better or not is something you will need to decide.
>>
>>> 2. How do I receive notification abut the event with the object name?
>>
>> Use information from here?:
>>
>> https://www.postgresql.org/docs/current/functions-event-triggers.html#PG-EVENT-TRIGGER-DDL-COMMAND-END-FUNCTIONS
> 
> Thx for the link
> So basically all I need to do is to call
> 
> SELECT pg_event_trigger_ddl_commands ()

And then unpack the information it returns.

> 
> right?
> 
> In both ODBC amd libpq interfaces?

It is not about the interface it is about, from link above:

"pg_event_trigger_ddl_commands returns a list of DDL commands executed 
by each user action, when invoked in a function attached to a 
ddl_command_end event trigger."



> 
> Thank you.
> 
> 
> 
>>
>>>
>>> Thank you.
>>>
>>>
>>
>> --
>> Adrian Klaver
>> adrian.klaver@aklaver.com
>>

-- 
Adrian Klaver
adrian.klaver@aklaver.com

On 2/7/25 11:43, Igor Korot wrote:
> Hi, Adrian,
> 
> 

> 
>     It is not about the interface it is about, from link above:
> 
>     "pg_event_trigger_ddl_commands returns a list of DDL commands executed
>     by each user action, when invoked in a function attached to a
>     ddl_command_end event trigger."
> 
> 
> Is there a sample code i can look at?

Search:

https://duckduckgo.com/?q=pg_event_trigger_ddl_commands+example&t=ffab&ia=web

and ye shall find:

https://stackoverflow.com/questions/23488228/how-to-get-sql-text-from-postgres-event-trigger

> Also what is PostgreSQL version this function is introduced?

At top  of Postgres doc pages are version specific links.

Go to:

https://www.postgresql.org/docs/current/functions-event-
triggers.html#PG-EVENT-TRIGGER-DDL-COMMAND-END-FUNCTIONS

and click back on versions until you don't find it.


> 
> Thank you.

-- 
Adrian Klaver
adrian.klaver@aklaver.com