Re: Time based lag tracking for logical replication

On 11 May 2017 at 08:32, Noah Misch <noah(at)leadboat(dot)com> wrote:
> On Sun, Apr 23, 2017 at 01:10:32AM +0200, Petr Jelinek wrote:
>> The time based lag tracking commit [1] added interface for logging
>> progress of replication so that we can report lag as time interval
>> instead of just bytes. But the patch didn't contain patch for the
>> builtin logical replication.
>>
>> So I wrote something that implements this.
>
> This is listed as a PostgreSQL 10 open item, but the above makes it sound like
> a feature to consider for v11, not a defect in v10. Why is this an open item?

It's an open item because at the time of the Lag Tracker commit it was
believed to be a single line of code that needed to be added to
Logical Replication to make it work with the Lag Tracker
functionality. It didn't make sense for me to add it while the LR code
was still being changed, even though we had code to do that.

Petr's new patch is slightly longer and needed review and some minor
code to add pacing delay.

My own delay in responding has been because of illness. You'll note
that I'd missed response on at least one other mail from you.
Apologies for that, it has set me back some way but I'm better now and
have caught up with other matters. Petr nudged me to look at this
thread again yesterday, so I had been looking at this over last few
days.

Attached patch is Petr's patch, slightly rebased with added pacing
delay, similar to that used by HSFeedback.

--
Simon Riggs http://www.2ndQuadrant.com/
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