Re: [HACKERS] make async slave to wait for lsn to be replayed

On 2018-02-02 19:41:37 +0000, Simon Riggs wrote:
> On 2 February 2018 at 18:46, Robert Haas <robertmhaas@gmail.com> wrote:
> > On Fri, Feb 2, 2018 at 3:46 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
> >> In PG11, I propose the following command, sticking mostly to Ants'
> >> syntax, and allowing to wait for multiple events before it returns. It
> >> doesn't hold snapshot and will not get cancelled by Hot Standby.
> >>
> >> WAIT FOR event [, event ...] options
> >>
> >> event is
> >> LSN value
> >> TIMESTAMP value
> >>
> >> options
> >> TIMEOUT delay
> >> UNTIL TIMESTAMP timestamp
> >> (we have both, so people don't need to do math, they can use whichever
> >> they have)
> >
> > WAIT FOR TIMEOUT sounds a lot like SELECT pg_sleep_for(), and WAIT
> > UNTIL TIMESTAMP sounds a lot like SELECT pg_sleep_until().
> 
> Yes, it sounds very similar. It's the behavior that differs; I read
> and agreed with yours and Thomas' earlier comments on that point.
> 
> As pointed out upthread, the key difference is whether it gets
> cancelled on Hot Standby and whether you can call it in a non-READ
> COMMITTED transaction.

Given that nobody has updated the patch or even discussed doing so, I
assume this would CF issue should now appropriately be classified as
returned with feedback?

Greetings,

Andres Freund