Re: Problem while setting the fpw with SIGHUP

On Thu, Apr 19, 2018 at 07:11:43PM +0530, Amit Kapila wrote:
> On Thu, Apr 19, 2018 at 7:19 AM, Michael Paquier <michael(at)paquier(dot)xyz> wrote:
>> And, er, actually, I was thinking again about the case where a user
>> wants to disable full_page_writes temporarily to do some bulk load and
>> then re-enable it. With the patch proposed to actually update the FPW
>> effect at checkpoint time, then a user would need to issue a manual
>> checkpoint after updating the configuration and reloading, which may
>> create more I/O than he'd want to pay for, then a second checkpoint
>> would need to be issued after the configuration comes back again.
>
> Why a second checkpoint? One checkpoint either manual or automatic
> should be enough to make the setting effective.

I was thinking about cases where users have say hourly cron jobs in
charge of doing some maintenance of update cleanups, where they would
need to be sure that full_page_writes are back online after doing the
bulk-load. In this case an extra checkpoint would be necessary to make
the parameter update effective.
--
Michael