Re: Online enabling of checksums

On 2018-Jul-31, Tom Lane wrote:

> Andres Freund <andres@anarazel.de> writes:
> > On 2018-07-31 23:20:27 +0200, Daniel Gustafsson wrote:
> >> Not really arguing for or against, but just to understand the reasoning before
> >> starting hacking.  Why do we feel that a restart (intended for safety here) in
> >> this case is a burden on a use-once process?  Is it from a usability or
> >> technical point of view?  Just want to make sure we are on the same page before
> >> digging in to not hack on this patch in a direction which isn’t what is
> >> requested.
> 
> > Having, at some arbitrary seeming point in the middle of enabling
> > checksums to restart the server makes it harder to use and to schedule.
> > The restart is only needed to fix a relatively small issue, and doesn't
> > save that much code.
> 
> Without taking a position on the merits ... I don't see how you can
> claim "it doesn't save that much code" when we don't have a patch to
> compare to that doesn't require the restart.  Maybe it will turn out
> not to be much code, but we don't know that now.

The ability to get checksums enabled is a killer feature; the ability to
do it with no restart ... okay, it's better than requiring a restart,
but it's not *that* big a deal.

In the spirit of supporting incremental development, I think it's quite
sensible to get the current thing done, then see what it takes to get
the next thing done.  Each is an improvement on its own merits.  And it
doesn't have to be made by the same people.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services