On 2018/06/12 22:22, Ashutosh Bapat wrote:
> -- create triggers, user may create different trigger functions one
> for each partition, unless s/he understands that the tables can share
> trigger functions
> create function trig_t1p1() returns trigger as $$ begin return new;
> end;$$ language plpgsql;
> create trigger trig_t1p1_1 before update on t1p1 execute procedure trig_t1p1();
> create trigger trig_t1p1_2 before update on t1p1 execute procedure trig_t1p1();
>
> create function trig_t1p2() returns trigger as $$ begin return new;
> end;$$ language plpgsql;
> create trigger trig_t1p2 before update on t1p2 execute procedure trig_t1p2();
>
> When this schema gets upgraded to v12 or whatever version supports
> BEFORE ROW triggers on a partitioned table and the user tries to
> create a trigger on a partitioned table
> 1. somehow the code has to detect that there are already triggers on
> the partitions so no need to create new triggers on the partitions. I
> don't see how this can be done, unless the user is smart enough to use
> the same trigger function for all partitions.
>
> 2. user has to drop those triggers and trigger functions and create
> trigger on the partitioned table.
>
> May be I am underestimating users but I am sure there will be some
> users who will end up with scenario.
Hmm, if a user *knowingly* makes triggers on different partitions call
different functions, then they wouldn't want to use the feature to create
the trigger on partitioned tables, because that feature implies same
trigger definition for all partitions.
Maybe, just as a reminder to users, we could mention in the docs that it
is in fact possible to call the same function from different triggers
(that is, triggers defined on different partitions) and that's what they
should do if they intend to later use the feature to define that same
trigger on the partitioned table.
Thanks,
Amit