Date: Fri, 9 Jun 2017 23:31:53 -0700
From: Noah Misch <noah@leadboat.com>
To: simon@2ndquadrant.com
Cc: Michael Paquier <michael.paquier@gmail.com>, wangchuanting@huawei.com,
	PostgreSQL mailing lists <pgsql-bugs@postgresql.org>,
	Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org
Subject: Re: BUG #14680: startup process on standby encounter a deadlock of
 TwoPhaseStateLock when redo 2PC xlog
Message-ID: <20170610063153.GA1619984@rfd.leadboat.com>
References: <20170531033228.1487.10124@wrigleys.postgresql.org>
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 <20170604222430.GA1547727@rfd.leadboat.com>
 <20170609061738.GB1612355@rfd.leadboat.com>
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On Thu, Jun 08, 2017 at 11:17:38PM -0700, Noah Misch wrote:
> On Sun, Jun 04, 2017 at 10:24:30PM +0000, Noah Misch wrote:
> > On Thu, Jun 01, 2017 at 01:07:53AM -0700, Michael Paquier wrote:
> > > On Wed, May 31, 2017 at 12:30 PM, Michael Paquier
> > > <michael.paquier@gmail.com> wrote:
> > > > On Wed, May 31, 2017 at 6:57 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > > >> wangchuanting@huawei.com writes:
> > > >>> startup process on standby encounter a deadlock of TwoPhaseStateLock when
> > > >>> redo 2PC xlog.
> > > >>
> > > >> Please provide an example of how to get into this state.
> > > >
> > > > That would help. Are you seeing in the logs something like "removing
> > > > future two-phase state from memory for XXX" or "removing stale
> > > > two-phase state from shared memory for XXX"?
> > > >
> > > > Even with that, the light-weight lock sequence taken in those code
> > > > paths look definitely wrong to me, we should not take twice
> > > > TwoPhaseStateLock in the same code path. I think that we should remove
> > > > the lock acquisitions in RemoveGXact() and PrepareRedoRemove, and then
> > > > upgrade the locks of PrescanPreparedTransactions() and
> > > > StandbyRecoverPreparedTransactions() to be exclusive. We still need to
> > > > keep a lock as CheckPointTwoPhase() may still be triggered by the
> > > > checkpoint. Tom, what do you think?
> > > 
> > > Attached is what I was thinking about for reference. I just came back
> > > from a long flight and I am pretty tired, so my brain may have missed
> > > something. I'll take again a look at this issue on Monday, an open
> > > item has been added for now.
> > 
> > [Action required within three days.  This is a generic notification.]
> > 
> > The above-described topic is currently a PostgreSQL 10 open item.  Simon,
> > since you committed the patch believed to have created it, you own this open
> > item.  If some other commit is more relevant or if this does not belong as a
> > v10 open item, please let us know.  Otherwise, 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
> update.  Refer to the policy on open item ownership:
> https://www.postgresql.org/message-id/20170404140717.GA2675809%40tornado.leadboat.com

IMMEDIATE ATTENTION REQUIRED.  This PostgreSQL 10 open item is long past due
for your status update.  Please reacquaint yourself with the policy on open
item ownership[1] and then reply immediately.  If I do not hear from you by
2017-06-11 07:00 UTC, I will transfer this item to release management team
ownership without further notice.

[1] https://www.postgresql.org/message-id/20170404140717.GA2675809%40tornado.leadboat.com


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