Re: left join with smaller table or index on (XXX is not null) to avoid upsert

On Mon, Jan 19, 2009 at 09:48, Grzegorz Jaśkiewicz <gryzman(at)gmail(dot)com> wrote:
> On Mon, Jan 19, 2009 at 4:43 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> But having said that: 8.4 will provide a standard trigger that
>> short-circuits vacuous updates, which you can apply to tables in which
>> you think vacuous updates are likely. It's your responsibility to place
>> the trigger so that it doesn't interfere with any other trigger
>> processing you may have.
>
> Tom, Can you point us to
> http://developer.postgresql.org/pgdocs/postgres/ where it is described
> in more detail ?

I assume he is talking about suppress_redundant_updates_trigger, see
http://developer.postgresql.org/pgdocs/postgres/functions-trigger.html