Re: max_standby_delay considered harmful

On Tue, 2010-05-04 at 23:06 -0400, Bruce Momjian wrote:

> Should I be concerned that we are redesigning HS features at this stage
> in the release?

We knew we had to have one final discussion on HS snapshots. This is it.

Tom has raised valid issues, all of which already known. If we can
address them, we should.

A straightforward patch [walrcv_timestamp.patch] to address all of those
points. (Posted 13 hours prior to your post. That it was ignored by all
while debate continued is one point of concern, for me, though there
seems to have been confusion as to what that patch actually was.)

Tom has also raised a separate proposal, though that hasn't yet been
properly explained and there has been much debate about what he actually
meant. It is possible there is something worthwhile there, if that
involves adding a new capability. Myself, Stephen, Josh and Greg say
that changing max_standby_delay so there is no bounded startup time
would be a bad thing, if that is its only behaviour in 9.0.

I will tidy up walrcv_timestamp.patch and apply on Thu evening unless
there are concise, rational objections to that patch, which I consider
to be a bug fix and not blocked by beta.

Tom raised 7 other main points, that following detailed investigation
have resulted in 2 minor bugs, 2 unresolved questions on the patch and 1
further request for code comments. The 2 bugs affect corner cases only
and so are minor. They will be fixed over next few days since not
instant fixes. Open items list updated with items mentioned here, plus
performance query discussed on other thread. Nothing much here likely to
cause a problem if we need to go beta immediately, IMO.

I am mostly unavailable for next few days. (Repairing bikeshed.)

Expect at least 3 commits from me over next few days.

--
Simon Riggs www.2ndQuadrant.com