Thread: Trigger does not work after partitioning

Trigger does not work after partitioning

From
"Raschkowski, Michael"
Date:

Hello,

 

I am using Postgres 12.1 on Windows 10.

 

I wrote the script for the partitioning of some tables and have noticed that some triggers do not work after partitioning. In attached example, you can see that the table test1 gets a trigger that sets the field instancenbr to 1 after each insertion.  Nevertheless, the field instancenbr stays to have NULL-Value.

 

Is it a bug or I have not taken something into account?

 

Thanks in advance!  

 

Viele Grüße / Kind regards,

Dr. Michael Raschkowski
Software Architect

Auconet GmbH - ein Unternehmen der Beta Systems Gruppe
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Attachment

Re: Trigger does not work after partitioning

From
Alvaro Herrera
Date:
On 2020-Mar-19, Raschkowski, Michael wrote:

> I am using Postgres 12.1 on Windows 10.
> 
> I wrote the script for the partitioning of some tables and have
> noticed that some triggers do not work after partitioning. In attached
> example, you can see that the table test1 gets a trigger that sets the
> field instancenbr to 1 after each insertion.  Nevertheless, the field
> instancenbr stays to have NULL-Value.

This has never worked, regardless of partitioning.  AFTER triggers
cannot usefully change the affected row; if you want to do that, you
need a BEFORE trigger.  The "return NEW" line is useless in an AFTER
trigger.

BEFORE triggers are not supported with partitioned tables (except in the
future Postgres 13, where I added that feature yesterday), but you can
add the trigger to each partition and it should work correctly.  Of
course, you'll need to add the trigger manually on each partition you
create or attach.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services