Re: pg_resetwal --next-transaction-id may cause database failed to restart.

On 2020-Jun-24, movead(dot)li(at)highgo(dot)ca wrote:

> >Maybe a better answer is to have a new switch in postmaster that creates
> >any needed files (incl. producing associated WAL etc); so you'd run
> >pg_resetwal -x some-value
> >postmaster --create-special-stuff
> >then start your server and off you go.
>
> As shown in the document, it looks like to rule a safe input, so I think it's better
> to rule it and add an option to focus write an unsafe value if necessary.

ISTM that a reasonable compromise is that if you use -x (or -c, -m, -O)
and the input value is outside the range supported by existing files,
then it's a fatal error; unless you use --force, which turns it into
just a warning.

> >Now maybe this is too much complication for a mechanism that really
> >isn't for general consumption anyway. I mean, if you're using
> >pg_resetwal, you're already playing with fire.
> Yes, that's true, I always heard the word "You'd better not use pg_walreset".
> But the tool appear in PG code, it's better to improve it than do nothing.

Sure.

--
Álvaro Herrera https://www.2ndQuadrant.com/
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