Re: Offline enabling/disabling of data checksums

On 12/27/18 11:39 AM, Magnus Hagander wrote:
>
>
> On Thu, Dec 27, 2018 at 2:15 AM Michael Paquier <michael@paquier.xyz
> <mailto:michael@paquier.xyz>> wrote:
>
>     On Wed, Dec 26, 2018 at 07:43:17PM +0100, Fabien COELHO wrote:
>     >> It adds an (now mandatory) --action parameter that takes either
>     verify,
>     >> enable or disable as argument.
>     >
>     > I'd rather have explicit switches for verify, enable & disable,
>     and verify
>     > would be the default if none is provided.
>
>     Okay, noted for the separate switches.  But I don't agree with the
>     point of assuming that --verify should be enforced if no switches are
>     defined.  That feels like a trap for newcomers of this tool..
>
>
> Defaulting to the choice that makes no actual changes to the data surely
> is the safe choice,a nd not a trap :)
>
> That said, this would probably be our first tool where you switch it
> between readonly and rewrite mode with just a switch, woudn't it? All
> other tools are either read-only or read/write at the *tool* level, not
> the switch level.
>

Eh? Isn't pg_rewind "modify by default" with --dry-run switch to run in
a read-only mode. So I'm not sure what you mean by "tool level" here.

FWIW I'd prefer sticking to the same approach for this tool too, i.e.
have a "dry-run" switch that makes it read-only. IMHO that's pretty
common pattern.