From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
---|---|
To: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
Cc: | Andres Freund <andres(at)anarazel(dot)de>, Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Rajeev rastogi <rajeev(dot)rastogi(at)huawei(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Dangling Client Backend Process |
Date: | 2015-10-19 16:06:33 |
Message-ID: | CA+TgmoYjTfsjgTPJTpW-KZ8w4Oia1k460qVHr5WkCGuJvLvssw@mail.gmail.com |
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Lists: | pgsql-hackers |
On Sat, Oct 17, 2015 at 4:52 PM, Alvaro Herrera
<alvherre(at)2ndquadrant(dot)com> wrote:
> Andres Freund wrote:
>> On 2015-10-14 17:33:01 +0900, Kyotaro HORIGUCHI wrote:
>> > If I recall correctly, he concerned about killing the backends
>> > running transactions which could be saved. I have a sympathy with
>> > the opinion.
>>
>> I still don't. Leaving backends alive after postmaster has died prevents
>> the auto-restart mechanism to from working from there on. Which means
>> that we'll potentially continue happily after another backend has
>> PANICed and potentially corrupted shared memory. Which isn't all that
>> unlikely if postmaster isn't around anymore.
>
> I agree. When postmaster terminates without waiting for all backends to
> go away, things are going horribly wrong -- either a DBA has done
> something stupid, or the system is misbehaving. As Andres says, if
> another backend dies at that point, things are even worse -- the dying
> backend could have been holding a critical lwlock, for instance, or it
> could have corrupted shared buffers on its way out. It is not sensible
> to leave the rest of the backends in the system still trying to run just
> because there is no one there to kill them.
Yep. +1 for changing this.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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