Re: Re: [COMMITTERS] pgsql: Checkpointer starts before bgwriter to avoid missing fsync reque

Simon Riggs <simon(at)2ndQuadrant(dot)com> writes:
> On 1 June 2012 14:29, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Surely that commit is useless. Fsync requests go into a queue in shared
>> memory, which had better have been set up by the postmaster. There is
>> no requirement that the receiving process exist before somebody can put
>> a request into the queue. If the queue overflows, the requestor has to
>> take care of the fsync itself, but that is independent of whether the
>> checkpointer is running yet.

> The problem I saw was about fsync queue message overflow, not actually
> missing fsyncs, so perhaps I worded the commit message poorly.

Ah. Well, as long as the overflowed fsyncs do get handled on the
requesting side, I see no bug here. No objection to changing the order
in which we launch the processes, but as Heikki says, it's not clear
that that is really going to make much difference.

regards, tom lane