Jan Wieck wrote:
> On 2/8/2007 3:32 PM, Bruce Momjian wrote:
>> Alvaro Herrera wrote:
>>> > > Is this a new policy that after discussion, all patches must be >
>>> > resubmitted with a summary and conclusions of the discussion? I can
>>> > > certainly do that for you, but just tell me if you are going to
>>> ask the > > same from everyone.
>>> > > No, I am asking only this time because I feel there was too much
>>> > disconnect between the patch and the extensive replication discussion
>>> > that few community members would see the connection.
>>> FYI, in my opinion the trigger addition is clearly useful to Mammoth
>>> Replicator as well.  In fact, it's so obviously useful that I didn't see
>>> a need to state that in the original thread where it was discussed.
>> Right, I know it is useful too, but I would like a layout of what it
>> does and why so everyone is clear on it.

Well how deep are we talking here? My understanding of what Jan wants to
do is simple.

Be able to declare which triggers are fired depending on the state of
the cluster.

In Jan's terms, the Origin or Subscriber. In Replicator terms the Master
or Slave.

This is useful because I may have a trigger on the Master and the same
trigger on the Slave. You do not want the trigger to fire on the Slave
because we are doing data replication. In short, the we replicate the
result, not the action.

However, you may want triggers that are on the Slave to fire separately.
A reporting server that generates materialized views is a good example.
Don't tie up the Master with what a Slave can do.


Joshua D. Drake

> I have no clue what got you into what you are doing here. But that shall
> not be my real concern. If you feel the need to do this sort of thing,
> be my guest. I will add the remaining changes to pg_rewrite, including
> the new support commands and changes to psql as well as pg_dump and
> resubmit the new patch with explanations that will hopefully help you to
> comprehend what and how this relatively small and fully backward
> compatible change in the trigger and rule firing mechanism will work and
> what existing problems it will solve.
> Regards,
> Jan


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