Re: [HACKERS] 9.4.1 -> 9.4.2 problem: could not access status of transaction 1

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Fri, Jun 5, 2015 at 12:00 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:
>> On 2015-06-05 11:43:45 -0400, Tom Lane wrote:
>>> So where are we on this? Are we ready to schedule a new set of
>>> back-branch releases? If not, what issues remain to be looked at?

>> We're currently still doing bad things while the database is in an
>> inconsistent state (i.e. read from SLRUs and truncate based on the
>> results of that). It's quite easy to reproduce base backup startup
>> failures.
>>
>> On the other hand, that's not new. And the fix requires, afaics, a new
>> type of WAL record (issued very infrequently). I'll post a first version
>> of the patch, rebased ontop of Robert's commit, tonight or tomorrow. I
>> guess we can then decide what we'd like to do.

> There are at least two other known issues that seem like they should
> be fixed before we release:

> 1. The problem that we might truncate an SLRU members page away when
> it's in the buffers, but not drop it from the buffers, leading to a
> failure when we try to write it later.

> 2. Thomas's bug fix for another longstanding but that occurs when you
> run his checkpoint-segment-boundary.sh script.

> I think we might want to try to fix one or both of those before
> cutting a new release. I'm less sold on the idea of installing
> WAL-logging in this minor release. That probably needs to be done,
> but right now we've got stuff that worked in early 9.3.X release and
> is now broken, and I'm in favor of fixing that first.

Okay, but if we're not committing today to a release wrap on Monday,
I don't see it happening till after PGCon.

regards, tom lane