Re: Hot Standby on git

On Thu, 2009-10-01 at 18:47 +0300, Heikki Linnakangas wrote:

> And if you could please review the changes I've been doing, just to
> make sure I haven't inadvertently introduced new bugs. That has
> happened before, as you've rightfully reminded me :-).

You posted 17 patches here.

I've reviewed/applied patches 1,3,4,5,6,7,9,10,13,14,15.
That leaves me with some form of issue on 2, 5, 8, 11, 12, 16 and 17.
Sounds a lot, but out of 41 patches in total to date, I have as yet
unresolved issues with 9.

Patch 0017 has significant changes to it, so I'm posting patches here
for further discussion. Main line thought is that I agree with the
changes you wanted to make and I've added a few extra things.

Commit message from repo:
Apply 0017-Revert-changes-to-subtrans.c-and-slru.c.-Instead-cal.patch
but with heavy modifications to fix a number of bugs and make associated
changes. First, StartupSubtrans() positioned itself at oldestXid, so
that when later running transactions complete they could find no page
for them to update and crash. Second, ExtendClog() expected to be able
to write WAL during recovery and so crashed after 32768 xids. This patch
also extends the patch to cover the recently added support for starting
Hot Standby from a shutdown checkpoint, which causes some refactoring.
Various comments reworded, including allowing a lock overflow to cause a
PENDING state, just as we do with subxid overflow. Another bug was also
found, in that failing to make subtrans entries from the initial
snapshot could lead to later abort records hanging because the topxid
was not set. Code is now similar in all code paths. Sounds like a lot of
changes, but mostly subtle changes rather than lengthy ones.

It seems highly likely that you'll find an error in my changes to your
changes also, but they do pass initial testing.

--
Simon Riggs www.2ndQuadrant.com