Re: Time-Delayed Standbys

On 2013-12-12 09:09:21 +0000, Simon Riggs wrote:
> >> * Add functionality (I propose)
> >> We can set negative number at min_standby_apply_delay. I think that
> >> this feature
> >> is for world wide replication situation. For example, master server is
> >> in
> >> Japan and slave server is in San Francisco. Japan time fowards than
> >> San
> >> Francisco time
> >> . And if we want to delay in this situation, it can need negative

> > This is because local time is recorded in XLOG. And it has big cost for
> > calculating global time.

Uhm? Isn't the timestamp in commit records actually a TimestampTz? And
thus essentially stored as UTC? I don't think this problem actually
exists?

> My suggestion would be to add the TZ to the checkpoint record. This
> way all users of WAL can see the TZ of the master and act accordingly.
> I'll do a separate patch for that.

Intuitively I'd say that might be useful - but I am not reall sure what
for. And we don't exactly have a great interface for looking at a
checkpoint's data. Maybe add it to the control file instead?

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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