RE: Time delayed LR (WAS Re: logical replication restrictions)

Dear Amit,

> > > It seems to me Kuroda-San has proposed this change [1] to fix the test
> > > but it is not clear to me why such a change is required. Why can't
> > > CHECK_FOR_INTERRUPTS() after waiting, followed by the existing below
> > > code [2] in LogicalRepApplyLoop() sufficient to handle parameter
> > > updates?

(I forgot to say, this change was not proposed by me. I said that there should be
modified. I thought workers should wake up after the transaction was committed.)

> So, why only honor the 'disable' option of the subscription? For
> example, one can change 'min_apply_delay' and it seems
> recoveryApplyDelay() honors a similar change in the recovery
> parameter. Is there a way to set the latch of the worker process, so
> that it can recheck if anything is changed?

I have not considered about it, but seems reasonable. We may be able to
do maybe_reread_subscription() if subscription parameters are changed
and latch is set.

Currently, IIUC we try to disable subscription regardless of the state, but
should we avoid to reread catalog if workers are handling the transactions,
like LogicalRepApplyLoop()?

Best Regards,
Hayato Kuroda
FUJITSU LIMITED