Re: UPDATE column without FK fires other FK triggers constraint check

Luca Looz <luca(dot)looz92(at)gmail(dot)com> writes:
> After some tests it seems that this happens when the same row is covered by
> more than 1 update in the same transaction even without any change.
> Is this an expected behavior? Why it happens?

Yes, see comment in RI_FKey_fk_upd_check_required:

* If the original row was inserted by our own transaction, we
* must fire the trigger whether or not the keys are equal. This
* is because our UPDATE will invalidate the INSERT so that the
* INSERT RI trigger will not do anything; so we had better do the
* UPDATE check. (We could skip this if we knew the INSERT
* trigger already fired, but there is no easy way to know that.)

Although this is talking about the BEGIN; INSERT; UPDATE; COMMIT case,
the code has no way to tell that apart from BEGIN; UPDATE; UPDATE; COMMIT.

regards, tom lane