Re: limiting hint bit I/O

"Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> writes:
> Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> The critical issue is whether the tuples get frozen while they're
>> still invisible to some transactions on the standby server.
>> That's when you get query cancellations.

> Oh, OK; I get that. That seems easy enough to at least mitigate to
> a large degree by some threshold GUC. But of course, the longer you
> wait to freeze so that you don't cancel queries on the standby, the
> more you pay to recalculate visibility, so it'd be a fussy thing to
> tune.

Yeah. Also, most of the argument for early freezing hinges on the hope
that it could happen before the tuples go to disk the first time, which
makes the window even narrower.

regards, tom lane