From: Noah Misch <noah@leadboat.com>
To: Thomas Munro <thomas.munro@enterprisedb.com>
Cc: Stephen Frost <sfrost@snowman.net>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: "could not reattach to shared memory" on buildfarm member dory
Date: Tue, 24 Apr 2018 07:06:46 +0000
Message-ID: <20180424070646.GA2693533@rfd.leadboat.com> (raw)
In-Reply-To: <CAEepm=0kRF7Hrd2R72FJLdQneV1HATjJM_ArbjZw=-ZF3RT7+Q@mail.gmail.com>
References: <25495.1524517820@sss.pgh.pa.us>
<20180423231855.GK27724@tamriel.snowman.net>
<CAEepm=0kRF7Hrd2R72FJLdQneV1HATjJM_ArbjZw=-ZF3RT7+Q@mail.gmail.com>
On Tue, Apr 24, 2018 at 11:37:33AM +1200, Thomas Munro wrote:
> On Tue, Apr 24, 2018 at 11:18 AM, Stephen Frost <sfrost@snowman.net> wrote:
> > Greetings,
> >
> > * Tom Lane (tgl@sss.pgh.pa.us) wrote:
> >> So far, dory has failed three times with essentially identical symptoms:
> >>
> >> 2018-04-23 19:57:10.624 GMT [2240] FATAL: could not reattach to shared memory (key=0000000000000190, addr=00000000018E0000): error code 487
> >> 2018-04-23 15:57:10.657 EDT [8836] ERROR: lost connection to parallel worker
> >> 2018-04-23 15:57:10.657 EDT [8836] STATEMENT: select count(*) from tenk1 group by twenty;
> >> 2018-04-23 15:57:10.660 EDT [3820] LOG: background worker "parallel worker" (PID 2240) exited with exit code 1
> >>
> >> Now how can this be? We've successfully reserved and released the address
> >> range we want to use, so it *should* be free at the instant we try to map.
> >
> > Yeah, that's definitely interesting.
>
> I wondered if another thread with the right timing could map something
> between the VirtualFree() and MapViewOfFileEx() calls, but we don't
> create the Windows signal handling thread until a bit later. Could
> there be any any other threads active in the process?
>
> Maybe try asking what's mapped there with VirtualQueryEx() on failure?
+1. An implementation of that:
https://www.postgresql.org/message-id/20170403065106.GA2624300%40tornado.leadboat.com
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To: pgsql-hackers@postgresql.org
Cc: noah@leadboat.com, thomas.munro@enterprisedb.com, sfrost@snowman.net, tgl@sss.pgh.pa.us, pgsql-hackers@lists.postgresql.org
Subject: Re: "could not reattach to shared memory" on buildfarm member dory
In-Reply-To: <20180424070646.GA2693533@rfd.leadboat.com>
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