On 1 June 2012 14:59, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Simon Riggs <simon@2ndQuadrant.com> writes:
>> On 1 June 2012 14:29, Tom Lane <tgl@sss.pgh.pa.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.
If I see those messages again, I guess you'll be right.
If that happens I suggest just adding a short wait at bgwriter startup.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services