Re: Enabling Checksums

On Thu, Apr 18, 2013 at 09:17:39AM +0100, Simon Riggs wrote:
> On 17 April 2013 22:36, Bruce Momjian <bruce@momjian.us> wrote:
> 
> >> > I would like to know the answer of how an upgrade from checksum to
> >> > no-checksum would behave so I can modify pg_upgrade to allow it.
> >>
> >> Why? 9.3 pg_upgrade certainly doesn't need it. When we get to 9.4, if
> >> someone has checksums enabled and wants to disable it, why is pg_upgrade
> >> the right time to do that? Wouldn't it make more sense to allow them to
> >> do that at any time?
> >
> > Well, right now, pg_upgrade is the only way you could potentially turn
> > off checksums.  You are right that we might eventually want a command,
> > but my point is that we currently have a limitation in pg_upgrade that
> > might not be necessary.
> 
> We don't currently have checksums, so pg_upgrade doesn't need to cope
> with turning them off in 9.3

True, 9.2 doesn't have checksums, while 9.3 will.  One point is that
pg_upgrade could actually be used to turn off checksums for 9.3 to 9.3
upgrades if no tablespaces are used.

> For 9.4, it might, but likely we've have a tool to turn them off
> before then anyway.

True.   Would we want pg_upgrade to still enforce matching checksum
modes for old and new servers at that point?  Eventually we will have to
decide that.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +