Re: pre-commit triggers

On 11/15/2013 07:01 PM, Andrew Dunstan wrote:
>
> Attached is a patch to provide a new event trigger that will fire on
> transaction commit. I have tried to make certain that it fires at a
> sufficiently early stage in the commit process that some of the evils
> mentioned in previous discussions on this topic aren't relevant.
>
> The triggers don't fire if there is no real XID, so only actual data
> changes should cause the trigger to fire.
I have not looked at the patch, but does it also run pre-rollback ?

If not, how hard would it be to make it so ?

> They also don't fire in single user mode, so that if you do something
> stupid like create a trigger that unconditionally raises an error you
> have a way to recover.
>
> This is intended to be somewhat similar to the same feature in the
> Firebird database, and the initial demand came from a client migrating
> from that system to Postgres.
>
> cheers
>
> andrew
>
>

--
Hannu Krosing
PostgreSQL Consultant
Performance, Scalability and High Availability
2ndQuadrant Nordic OÜ