Re: Time based lag tracking for logical replication

On Fri, May 05, 2017 at 07:07:26AM +0000, Noah Misch wrote:
> On Wed, May 03, 2017 at 08:28:53AM +0200, Simon Riggs wrote:
> > On 23 April 2017 at 01:10, Petr Jelinek <petr(dot)jelinek(at)2ndquadrant(dot)com> wrote:
> > > Hi,
> > >
> > > 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. I didn't like all that much
> > > the API layering in terms of exporting the walsender's LagTrackerWrite()
> > > for use by plugin directly. Normally output plugin does not have to care
> > > if it's running under walsender or not, it uses abstracted write
> > > interface for that which can be implemented in various ways (that's how
> > > we implement SQL interface to logical decoding after all). So I decided
> > > to add another function to the logical decoding write api called
> > > update_progress and call that one from the output plugin. The walsender
> > > then implements that new API to call the LagTrackerWrite() while the SQL
> > > interface just does not implement it at all. This seems like cleaner way
> > > of doing it.
> > >
> > > Thoughts?
> >
> > Agree cleaner.
> >
> > I don't see any pacing or comments about it, nor handling of
> > intermediate messages while we process a large transaction.
> >
> > I'll look at adding some pacing code in WalSndUpdateProgress()
>
> [Action required within three days.]
>
> Simon, I understand, from an annotation on the open items list, that you have
> volunteered to own this item. Please observe the policy on open item
> ownership[1] and send a status update within three calendar days of this
> message. Include a date for your subsequent status update. Testers may
> discover new open items at any time, and I want to plan to get them all fixed
> well in advance of shipping v10. Consequently, I will appreciate your efforts
> toward speedy resolution. Thanks.
>
> [1] https://www.postgresql.org/message-id/20170404140717.GA2675809%40tornado.leadboat.com

This PostgreSQL 10 open item is past due for your status update. Kindly send
a status update within 24 hours, and include a date for your subsequent status
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