From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Drouvot, Bertrand <bdrouvot@amazon.com>
Cc: Masahiko Sawada <masahiko.sawada@2ndquadrant.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Add Information during standby recovery conflicts
Date: Mon, 30 Nov 2020 15:25:28 -0300
Message-ID: <20201130182528.GA1854@alvherre.pgsql> (raw)
In-Reply-To: <fafa607c-9e85-b742-ab46-2ee807ab9364@oss.nttdata.com>
On 2020-Dec-01, Fujii Masao wrote:
> + if (proc)
> + {
> + if (nprocs == 0)
> + appendStringInfo(&buf, "%d", proc->pid);
> + else
> + appendStringInfo(&buf, ", %d", proc->pid);
> +
> + nprocs++;
>
> What happens if all the backends in wait_list have gone? In other words,
> how should we handle the case where nprocs == 0 (i.e., nprocs has not been
> incrmented at all)? This would very rarely happen, but can happen.
> In this case, since buf.data is empty, at least there seems no need to log
> the list of conflicting processes in detail message.
Yes, I noticed this too; this can be simplified by changing the
condition in the ereport() call to be "nprocs > 0" (rather than
wait_list being null), otherwise not print the errdetail. (You could
test buf.data or buf.len instead, but that seems uglier to me.)
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To: pgsql-hackers@postgresql.org
Cc: alvherre@alvh.no-ip.org, masao.fujii@oss.nttdata.com, sawada.mshk@gmail.com, bdrouvot@amazon.com, masahiko.sawada@2ndquadrant.com, horikyota.ntt@gmail.com
Subject: Re: Add Information during standby recovery conflicts
In-Reply-To: <20201130182528.GA1854@alvherre.pgsql>
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