Robert Haas <> writes:
> On Mon, Jun 19, 2017 at 11:59 AM, Tom Lane <> wrote:
>> I don't think it's a bug, I think it's an intentional design tradeoff.
>> To suppress an update in this case, the trigger would have to grovel
>> through the individual fields and detoast them before comparing.
>> That would add a lot of cycles, and only seldom add successes.
>> Possibly we should adjust the documentation so that it doesn't imply
>> that this trigger guarantees to suppress every no-op update.

> That doesn't sound like a very plausible argument to me.  I don't
> think that a proposal to add a function named
> sometimes_suppress_redundant_updates_trigger() would've attracted many
> votes.

You'd be wrong.  The entire point of this trigger is to save cycles,
so having it eat a lot of cycles only to fail is not an improvement.

                        regards, tom lane

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